date:20100228

Hi

That's the one, right down to the description of the pots. If it doesn't become 
a working counter, it's cheap enough to be a parts donor. Of course having 
multiple counters all with the exact same broken parts doesn't do much good 
.

For the external arm level control I might go for a fixed level and forget 
about the pot entirely. It's been about 20 years since I've played with a 5370, 
so Im drawing a blank on the display update control.

Bob


On Feb 28, 2010, at 12:10 AM, Mark Sims wrote:

 
 If it's the one that I think it is...  look closely at the photo.  The shafts 
 on two of the pots are sheared off at the panel.   These are the display 
 update control and the external arming level control.   These were custom HP 
 pots with a funky (and delicate)  switch.  They had brittle plastic shafts.   
  Gee,  how do I know this...  could it be that a large percentage of the 
 5370's for sale have the same defect?
 
 Luckily those controls are not too critical for normal operation.  They can 
 be replaced with regular (switchless) pots if you jumper the switch pads 
 correctly.  Be careful,  there were two different layouts to those controls.
 
 
 --
 So exactly how did you know that I bought a (cheap) 5370B a few hours ago on 
 the e-place
 _
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Re: [time-nuts] Looking for a 5370 red digit cover/window

Jim
Worse case if you do not find the replacement
Digi-key and I would guess mouser caries the filter material for a
reasonable price.
(At least they did)
I needed some to replace a missing piece on a HP 5360 and HP 8505.


On Sat, Feb 27, 2010 at 10:44 PM, Jim Cotton jim.cot...@wmich.edu wrote:


 I need the red plastic digit cover/window [approximately 1 3/4 x 14 3/4]
 to complete the repair of a HP 5370 counter/timer.  I don't care if it says
 5370A or B.  I assume that no major change occurred other than the
 unit identifier changing.  Perhaps someone can correct me if I am wrong in
 making this assumption.

 It would be nice to get the bezel clip/strip too, however I suspect that
 they tend to disintegrate during removal of the red display cover.

 Does anyone have this available from a parts chassis in their lab?

 I would be happy to pay a reasonable price plus postage.  I am located in
 Kalamazoo, Michigan, USA.

 Jim Cotton
 n8qoh

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Re: [time-nuts] My DIY frequency counter and a request for help

You went quite??

On Sat, Feb 27, 2010 at 9:54 AM, paul swed paulsw...@gmail.com wrote:

 Gerard you have some great comments already and welcome back to the
 electronics hobby.
 A couple of things.
 Curious about whats on the board etc.

 Here would be my thoughts.
 If the same 10 MC signal thats the reference is also the input.
 Then any funny numbers are the process leftovers or jitter.
 I think this would also help you find the max resolution quickly.
 Once you introduce external signals it becomes more difficult to understand
 whats happening.

 I built a LORAN C simulator driven by a Rb reference.
 When I drive the austron 2100 with the same reference the austron
 ultimately settles at its max resolution of 1 E-13.
 Very interesting first project you clearly have a good background in
 applied electronics


 On Sat, Feb 27, 2010 at 7:36 AM, Bruce Griffiths 
 bruce.griffi...@xtra.co.nz wrote:

 Gerard PG5G wrote:

Hello all,
First post here, so I'll start with a quick introduction. I trained as
an electronic engineer but don't work in that field any more, which
 has
given me the appetite back to do some electronic engineering as a
hobby. I have been a licensed ham for over 25 years (more than 60% of
my life I realised the other day) and used to be rather active on HF
 as
PA3DQW. At the moment I live in the UK where I am licensed as M0AIU.
I recently designed and build a frequency counter and I need some help
with verifying its performance. I believe it gives me 11 digits in 1
second. I say believe because I have not got the hardware to verify
this. At the moment my assumption is based on calculations and limited
testing with the equipment available to me.
My counter is a continuous time stamping reciprocal counter. I
implemented this as a USB powered device, with the hardware taking the
time stamps and sending it over USB to a windows PC. Some software
written in C++ takes care of analysing the data.
The hardware takes 5000 time stamps per second using a high speed TDC.
The hardware is a single PCB measuring about 50 by 80 mm. it requires
an external 10MHz reference and apart from using this as the time base
it also uses this for self-calibration of the TDC. The unit requires
 no
further calibration.
The PC software takes these time stamps and the associated counts and
uses regression to calculate the slope. This slope represents the
frequency of the input signal. I am sure people on here are familiar
with the counters made by Pendulum, and I have to confess that their
marketing material was helpful in putting this thing together.
Since the hardware is true zero dead time, the final capabilities of
this counter are determined by software. At the moment I can
simultaneously display the input at multiple gate times (see the
attached screen shot). For gate times over 1 second I have the option
to use overlapping gates, so that the display gets updated every
second.
Because there is no dead time I can also calculate Allan Deviation.
 The
two displays at the bottom of the page show both normal and
 overlapping
Allan deviation at tau=10s. I am still working on the software to do
this at multiple tau in real time and display it as a graph and a
table.
So, after this lengthy introduction here is my request for some
assistance. Is there somebody on the list who can assist me in
verifying the performance of this frequency counter? Ideally somebody
with access to two highly stable and known frequency sources. I can
send the hardware by mail, but if there happens to be somebody with
this kind of gear not too far from where I am (50 north of London) I
will travel. In exchange you get to keep the hardware and will be
supplied with whatever software I come up with.
Thanks in advance and regards,
Gerard, PG5G


 Are you calculating ADEV and MDEV using the slopes determined by the
 regression fit?
 If so, what you calculate isn't ADEV or MDEV.

 You need to use the raw timestamps taken at a rate of 5000/sec directly to
 produce estimates of ADEV, MDEV.
 What is the resolution of the TDC?

 Bruce



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Re: [time-nuts] Looking for a 5370 red digit cover/window

2010-02-28 Thread J. L. Trantham

I have a 5370B that is missing about half of it's red plastic digit
cover/window and would like to repair it as well.  Do you have a suggestion
as to how to start searching Digi-Key and Mouser?

Thanks,

Joe

-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of paul swed
Sent: Sunday, February 28, 2010 9:09 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Looking for a 5370 red digit cover/window


Jim
Worse case if you do not find the replacement
Digi-key and I would guess mouser caries the filter material for a
reasonable price. (At least they did) I needed some to replace a missing
piece on a HP 5360 and HP 8505.


On Sat, Feb 27, 2010 at 10:44 PM, Jim Cotton jim.cot...@wmich.edu wrote:


 I need the red plastic digit cover/window [approximately 1 3/4 x 14 
 3/4] to complete the repair of a HP 5370 counter/timer.  I don't care 
 if it says 5370A or B.  I assume that no major change occurred other 
 than the unit identifier changing.  Perhaps someone can correct me if 
 I am wrong in making this assumption.

 It would be nice to get the bezel clip/strip too, however I suspect 
 that they tend to disintegrate during removal of the red display 
 cover.

 Does anyone have this available from a parts chassis in their lab?

 I would be happy to pay a reasonable price plus postage.  I am located 
 in Kalamazoo, Michigan, USA.

 Jim Cotton
 n8qoh

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Re: [time-nuts] DMTD Mixer Terminations

Hi

Putting The C on the feedback R in a positive gain setup is only going to take 
the roll off gain down to 1. Doing the same with an inverting amp or using a 
series R / cap to ground will drop the gain a lot more in the roll off region. 

I would worry about any resistor that's marked as 10K and reads 20K. It's 
likely noisy. 

A typical DBM has a loss of 5 to 7 db when not in compression. With a +7  to 
+10 dbm  drive that should give you an output of 0 to 2 dbm . The mixer output 
should be in the .6 to .8 V p-p range into 50 ohms. You should get about twice 
that on the beat note running into a load  500 ohms. A gain of  20 should be 
plenty. That would give you .6 x 2 x 20 = 24 V p-p out of the amp. 

If you rf short the output of the mixer you may double the beat note again 
(total of 4X the 50 ohm value). Net would be a 2.4 to 3.2 V p-p beat note. 
Anything much over a gain of 10 would be a problem then. This is one of the 
cases where 2 X 2 probably does not = 4, so measurements are indeed in order.


Bob




On Feb 28, 2010, at 1:01 AM, Brian Kirby wrote:

 The values in the schematics are wrong for the op amp gain.  The drawing was 
 from an earlier drawing where I made a preamp to start checks on the mixers, 
 and I sent it to you (Bruce G).  Thats when you determined I did not have 
 enough gain to get near the noise floor.  The THAT1512/1646 ICs were ordered 
 to make a new preamp for the future measurements on the mixers.
 
 When I use the scope and check the outputs of the IC, I have 20 volts peak to 
 peak, sine-wave.  I know from previous readings I see about 500 mv p-p out of 
 the mixer.
 
 I went down to the bench and the resistors I used were still there (I bought 
 several taped reels of Dale RN55D resistors when a local business went out).  
 I used 294 ohms and 14.9  kilo-ohms, for a gain of 50 (the power rails are 
 +/- 15 volts).  Also not shown on the schematic is a 0.47 uF cap around the 
 14.9 kilo-ohm resistor.  I think I was trying to limit the bandwidth to 
 around 15 hertz.
 
 Also the resistor going between the op amp and the limiting diodes was marked 
 10K, its 20K.  The diodes are 1N4148.  Corrected drawing attached.
 
 This is what happens to time nuts who can only play on the weekend and stay 
 up all nightand my employer just thinks I party too hard.for Monday 
 mornings.
 
 
 
 Brian KD4FM
 
 
 
 Bruce Griffiths wrote:
 The LT1037 is shown with a gain of ~1690x, if this amplifier is used to 
 amplify the beat frequency signal, it will saturate.
 Opamp recovery from saturation is poorly documented and may be very slow.
 It would be better to use some diodes in the amplifier feedback network to 
 limit the large signal gain to 5x (so that the LT1037 remains stable as it 
 isn't unity gain stable).
 This will ensure a somewhat faster recovery from overload as the LT1037 then 
 avoids saturation and the opamp input stage remains in the linear region.
 
 Bruce
 
 Bob Camp wrote:
 Hi
 
 Assuming that the junction of the back to back diodes goes trough a chunk 
 of coax to get to the counter:
 
 You are forming a low pass filter with the 10K resistor and the coax 
 capacitance. The LT1037 is quite happy driving a 600 ohm load. You could 
 easily drop the impedance at that point below 300 ohms. That should give 
 you a faster edge into the counter.
 
 You also should check the slew rate performance of the 1037. You don't want 
 the op amp to be slew rate limited.
 
 Bob
 
 
 On Feb 27, 2010, at 12:41 PM, Brian Kirby wrote:
 
  
 I am in the process of designing a DMTD system.  As an experiment to do 
 basic measurements on the chosen mixer, I used a capacitor (0.01 uF) in 
 series to ground with a 47 ohm metal film resistor.  Where the capacitor 
 and resistor meets, another resistor is attached (390 ohms) that goes to 
 ground.  The idea is to provide a 50 ohm termination at 20 Mhz and a 
 lighter termination at audio frequencies.  I seen this is a NBS note and I 
 can say, its a starting point for my experiments.
 
 This (my) system is designed for 10 Mhz, using a 10 hertz beat.  A 
 schematic is attached of what I am experimenting with at the moment.  A 
 HP5370B is the recording instrument.  The noise floor from 1 days 
 observations show  2x10-11 at 0.1 seconds, 2x10-12 at 1 sec, 5x10-13 at 10 
 sec, 6x10-14 at 100 sec, 7x10-15 at 1000 sec, and 7x10-16 at 10,000 secs.  
  It will be interesting when the project is completed to see how much 
 improvement there will be.
 
 As I understand (or learning..) mixer performance is the key to the DMTD 
 system.   It occurs to me that maybe a capacitor designed for 50 ohms at 
 20 mhz may be a better termination (for the IF port) for this mixer.  A 16 
 pF capacitor is 50 ohms at 20 mhz, and for comparison at 10 hertz, it 
 would be 100 meg-ohms, which would give maximum amplitude at 10 hertz.   
 As I understand, a capacitor terminated mixer will give a triangle wave 
 output, which is very beneficial to the design

Re: [time-nuts] Rack-mounting an LPRO? (Heatpipe cooler)

2010-02-28 Thread Joe Gwinn

At 2:02 AM + 2/28/10, time-nuts-requ...@febo.com wrote:

Date: Sat, 27 Feb 2010 20:02:05 -0600
From: Ed Palmer ed_pal...@sasktel.net
Subject: Re: [time-nuts] Rack-mounting an LPRO?
To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Message-ID: 4b89ce9d.4060...@sasktel.net
Content-Type: text/plain; charset=iso-8859-1; Format=flowed

Sorry, the pictures got lost.  Let's try again.

Ed Palmer wrote:

 What else is going to be in the rack?  If your 1U enclosure is packed
 in tight between other devices there might be no cooling at all.  You
 might need a fan to move some air.

 I don't know if you can find something like this, but I scavenged heat
 sinks from an old Compaq DL760 server that might fit your situation. 
 Here's what the heat sink looks like.  The aluminum plate is about

 1/4 (6.4 mm) thick.  Notice the heat pipes.

 Here's what it looks like on the LPRO.  You'll have to drill holes in
 the plate to match the LPRO.

 It's not perfect, but it certainly does the job - particularly if you
 had a fan blowing through the fins.  The total height is about 1.75
 (45 mm).

 But remember, the more you cool the LPRO, the more power it will draw
 to keep itself warm so you don't want to overdo the cooling.

  Ed

[snip]
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The aluminum fin and copper pipe assembly integrated with the 
heatsink plate is most likely a heat pipe of some kind, as that's 
what Thermacore makes.  It's a model 2644, from the nameplate, but no 
joy at the Thermacore.com website.

Joe Gwinn

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Re: [time-nuts] Rack-mounting an LPRO? (Heatpipe cooler)

A few words of caution here.

I have run compact rubidiums for a number of years. It is *very* tempting to
skimp on the heat sink. Cooling something that's heating it's self up sounds
silly.

Having tried the not much heat sink approach several times (I'm a slow
learner). The rubidium does die fairly soon. Properly cooled they last for a
long time. You need to get the baseplate below 40 C. Getting it below 30 C
might be better, but that's impractical in most settings.

The units dump around 10 watts of heat. The number will vary depending on the
supply voltage, the exact baseplate temperature, and the exact model. If your
normal room temperature is 20 C, 10 watts and a rise to 40 gives you 2 C/W.

In a tightly packed rack, in the summer, at high supply voltage, the heat sink
required can easily get to 1 C/W. My answer to that is to move the rubidium
out of the rack or simply turn it off when things get that warm.

Fans are a good way to improve the efficiency of any heat sink. The problem
here is that rubidiums are sensitive to magnetic field. Having a device with a
magnetic motor in it right next to one probably is a bad idea. If you put in
fans, put them in the back of the case, and keep them away from the rubidium.

Bob

On Feb 28, 2010, at 10:55 AM, Joe Gwinn wrote:

At 2:02 AM + 2/28/10, time-nuts-requ...@febo.com wrote:
Date: Sat, 27 Feb 2010 20:02:05 -0600
From: Ed Palmer ed_pal...@sasktel.net
Subject: Re: [time-nuts] Rack-mounting an LPRO?
To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Message-ID: 4b89ce9d.4060...@sasktel.net
Content-Type: text/plain; charset=iso-8859-1; Format=flowed

Sorry, the pictures got lost. Let's try again.

Ed Palmer wrote:
What else is going to be in the rack? If your 1U enclosure is packed
in tight between other devices there might be no cooling at all. You
might need a fan to move some air.

I don't know if you can find something like this, but I scavenged heat
sinks from an old Compaq DL760 server that might fit your situation.
Here's what the heat sink looks like. The aluminum plate is about
1/4 (6.4 mm) thick. Notice the heat pipes.

Here's what it looks like on the LPRO. You'll have to drill holes in
the plate to match the LPRO.

It's not perfect, but it certainly does the job - particularly if you
had a fan blowing through the fins. The total height is about 1.75
(45 mm).

But remember, the more you cool the LPRO, the more power it will draw
to keep itself warm so you don't want to overdo the cooling.

[snip]
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The aluminum fin and copper pipe assembly integrated with the heatsink plate
is most likely a heat pipe of some kind, as that's what Thermacore makes.
It's a model 2644, from the nameplate, but no joy at the Thermacore.com
website.

Joe Gwinn

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Re: [time-nuts] Rack-mounting an LPRO?

2010-02-28 Thread Scott Mace

I have a Datum Rubidium Frequency Standard, which is a 1U aluminum 
chassis that is about 2mm thick.  It contains a LPRO and a 24V/5V power 
supply with room to spare.  I installed a Fury GPSDO and a small DC-DC 
converter in the same enclosure.  The top cover is vented.  The chassis 
stays slightly warm and the LPRO appears to work well even with moderate 
HVAC cycling (as long as the chassis is in the rack with the door closed).


Scott

On 02/27/2010 04:30 PM, Paul Boven wrote:

Dear time-nuts,

I've just bought a used LPRO-101 which should get a permanent home
inside an instrument rack. I've also found a very nice 1U high metal
case, and a fitting 24V 1U power supply - leaving plenty of room for a
distribution amp and a microcontroller to log things like lamp and Xtal
voltage.

The rackmount enclosure is 1U high, and seems to be made of 1mm thick
galvanized steel. Would that make a good enough baseplate for the LPRO?
Would I need to do anything to improve the thermal contact between the
rubidium oscillator and the baseplate, and if so, any recommendations on
what to use there? The LPRO User's guide and integration guidelines
recommend 2degC/W thermal resistance (for up to 50degC ambient), and
using some special thermal tape that will probably be very hard to get
at these days. If any of you has already put something like this
together, I'd be very interested in your suggestions.

Regards, Paul Boven - PE1NUT

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Re: [time-nuts] Looking for a 5370 red digit cover/window

I found them in the led section
Try led filter???

On Sun, Feb 28, 2010 at 10:25 AM, J. L. Trantham jlt...@att.net wrote:

 I have a 5370B that is missing about half of it's red plastic digit
 cover/window and would like to repair it as well.  Do you have a suggestion
 as to how to start searching Digi-Key and Mouser?

 Thanks,

 Joe

 -Original Message-
 From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
 Behalf Of paul swed
 Sent: Sunday, February 28, 2010 9:09 AM
 To: Discussion of precise time and frequency measurement
 Subject: Re: [time-nuts] Looking for a 5370 red digit cover/window


 Jim
 Worse case if you do not find the replacement
 Digi-key and I would guess mouser caries the filter material for a
 reasonable price. (At least they did) I needed some to replace a missing
 piece on a HP 5360 and HP 8505.


 On Sat, Feb 27, 2010 at 10:44 PM, Jim Cotton jim.cot...@wmich.edu wrote:

 
  I need the red plastic digit cover/window [approximately 1 3/4 x 14
  3/4] to complete the repair of a HP 5370 counter/timer.  I don't care
  if it says 5370A or B.  I assume that no major change occurred other
  than the unit identifier changing.  Perhaps someone can correct me if
  I am wrong in making this assumption.
 
  It would be nice to get the bezel clip/strip too, however I suspect
  that they tend to disintegrate during removal of the red display
  cover.
 
  Does anyone have this available from a parts chassis in their lab?
 
  I would be happy to pay a reasonable price plus postage.  I am located
  in Kalamazoo, Michigan, USA.
 
  Jim Cotton
  n8qoh
 
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Re: [time-nuts] Rack-mounting an LPRO? (Heatpipe cooler)

An approach is to put just the rb unit in say the basement.
Its always cooler (at least mine is)
The area I work in can get pretty warm in the summer if I am gone for a week
This approach solves that problem pretty well

On Sun, Feb 28, 2010 at 11:25 AM, Bob Camp li...@rtty.us wrote:

A few words of caution here.

I have run compact rubidiums for a number of years. It is *very* tempting
to skimp on the heat sink. Cooling something that's heating it's self up
sounds silly.

The units dump around 10 watts of heat. The number will vary depending on
the supply voltage, the exact baseplate temperature, and the exact model. If
your normal room temperature is 20 C, 10 watts and a rise to 40 gives you 2
C/W.

In a tightly packed rack, in the summer, at high supply voltage, the heat
sink required can easily get to 1 C/W. My answer to that is to move the
rubidium out of the rack or simply turn it off when things get that warm.

Fans are a good way to improve the efficiency of any heat sink. The problem
here is that rubidiums are sensitive to magnetic field. Having a device with
a magnetic motor in it right next to one probably is a bad idea. If you put
in fans, put them in the back of the case, and keep them away from the
rubidium.

Bob

On Feb 28, 2010, at 10:55 AM, Joe Gwinn wrote:

Sorry, the pictures got lost. Let's try again.

Ed Palmer wrote:
What else is going to be in the rack? If your 1U enclosure is packed
in tight between other devices there might be no cooling at all. You
might need a fan to move some air.

Here's what it looks like on the LPRO. You'll have to drill holes in
the plate to match the LPRO.

It's not perfect, but it certainly does the job - particularly if you
had a fan blowing through the fins. The total height is about 1.75
(45 mm).

But remember, the more you cool the LPRO, the more power it will draw
to keep itself warm so you don't want to overdo the cooling.

-- next part --
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Name: 2.jpg
Type: image/jpeg
Size: 33025 bytes
Desc: not available
URL:
http://www.febo.com/pipermail/time-nuts/attachments/20100227/9f21a5a8/attachment-0001.jpg

The aluminum fin and copper pipe assembly integrated with the heatsink
plate is most likely a heat pipe of some kind, as that's what Thermacore
makes. It's a model 2644, from the nameplate, but no joy at the
Thermacore.com website.

Joe Gwinn

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Re: [time-nuts] Rack-mounting an LPRO? (Heatpipe cooler)

2010-02-28 Thread Ed Palmer

Joe Gwinn wrote:

At 2:02 AM + 2/28/10, time-nuts-requ...@febo.com wrote:

Date: Sat, 27 Feb 2010 20:02:05 -0600
From: Ed Palmer ed_pal...@sasktel.net
Subject: Re: [time-nuts] Rack-mounting an LPRO?
To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Message-ID: 4b89ce9d.4060...@sasktel.net
Content-Type: text/plain; charset=iso-8859-1; Format=flowed

Sorry, the pictures got lost.  Let's try again.

Ed Palmer wrote:

 What else is going to be in the rack?  If your 1U enclosure is packed
 in tight between other devices there might be no cooling at all.  You
 might need a fan to move some air.

 I don't know if you can find something like this, but I scavenged heat
 sinks from an old Compaq DL760 server that might fit your 
situation.  Here's what the heat sink looks like.  The aluminum 
plate is about

 1/4 (6.4 mm) thick.  Notice the heat pipes.

 Here's what it looks like on the LPRO.  You'll have to drill holes in
 the plate to match the LPRO.

 It's not perfect, but it certainly does the job - particularly if you
 had a fan blowing through the fins.  The total height is about 1.75
 (45 mm).

 But remember, the more you cool the LPRO, the more power it will draw
 to keep itself warm so you don't want to overdo the cooling.

  Ed

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The aluminum fin and copper pipe assembly integrated with the heatsink 
plate is most likely a heat pipe of some kind, as that's what 
Thermacore makes.  It's a model 2644, from the nameplate, but no joy 
at the Thermacore.com website.

Joe Gwinn

If you want to find that heatsink, you'll probably have better luck with 
the Compaq part # which is 190416-002 or just look for a used Xeon 
processor that has that heat sink on it.  Note that different servers 
used different heat sinks so you have to see a picture.  Right now there 
are more than 20 CPUs with this heatsink on auction at the site we all 
love to hate.

Ed

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[time-nuts] DIY frequency counter help (Gerard PG5G)

2010-02-28 Thread Murray Greenman

Gerard,
By now you've no doubt had more offers to assist than you need, and in
particular from far more local enthusiasts than me.

However, if I can help answer any particular points, I would be pleased
to do so. My reason for suggesting this is that I have available a
Pendulum CNT-90 counter, plus several very good references, both
traceable and high stability (though as you can imagine often not both
at once!)

I've designed my own counters in the past, but nothing on the scale of
yours. Well done!

73,
Murray ZL1BPU


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[time-nuts] DIY Frequency Counter

2010-02-28 Thread Martyn Smith


Gerard,

I just read your post about your DIY counter and asking for help.

I'm not sure when you actually wrote it.

I'm based in Chelmsford Essex and can give you some help.

I have multiple frequency standards as well as 4 x SR620 timer counters.

Let me know if I can be of help.

Regards

Martyn



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Re: [time-nuts] DMTD Mixer Terminations

My simulations indicate that terminating the Mixer IF port in an RF 
short (with both RF and LO ports saturated) increases the beat frequency 
zero crossing slope by more than a factor of 2 (exact value depends on 
mixer component characteristics) but doesnt significantly increase the 
beat frequency amplitude over that with a high value resistive 
termination. To achieve this the IF port termination impedance needs to 
be high at the beat frequency and its significant harmonics. The value 
above which the impedance is considered high depends on mixer details 
such as transformer turns ratio, RF source impedance, diode 
characteristics and RF input levels, etc.


Bruce

Bob Camp wrote:

Hi

Putting The C on the feedback R in a positive gain setup is only going to take the 
roll off gain down to 1. Doing the same with an inverting amp or using a 
series R / cap to ground will drop the gain a lot more in the roll off region.

I would worry about any resistor that's marked as 10K and reads 20K. It's 
likely noisy.

A typical DBM has a loss of 5 to 7 db when not in compression. With a +7  to +10 
dbm  drive that should give you an output of 0 to 2 dbm . The mixer output should 
be in the .6 to .8 V p-p range into 50 ohms. You should get about twice that on 
the beat note running into a load  500 ohms. A gain of  20 should be plenty. 
That would give you .6 x 2 x 20 = 24 V p-p out of the amp.

If you rf short the output of the mixer you may double the beat note again 
(total of 4X the 50 ohm value). Net would be a 2.4 to 3.2 V p-p beat note. Anything much 
over a gain of 10 would be a problem then. This is one of the cases where 2 X 2 probably 
does not = 4, so measurements are indeed in order.


Bob




On Feb 28, 2010, at 1:01 AM, Brian Kirby wrote:

   

The values in the schematics are wrong for the op amp gain.  The drawing was 
from an earlier drawing where I made a preamp to start checks on the mixers, 
and I sent it to you (Bruce G).  Thats when you determined I did not have 
enough gain to get near the noise floor.  The THAT1512/1646 ICs were ordered to 
make a new preamp for the future measurements on the mixers.

When I use the scope and check the outputs of the IC, I have 20 volts peak to 
peak, sine-wave.  I know from previous readings I see about 500 mv p-p out of 
the mixer.

I went down to the bench and the resistors I used were still there (I bought 
several taped reels of Dale RN55D resistors when a local business went out).  I 
used 294 ohms and 14.9  kilo-ohms, for a gain of 50 (the power rails are +/- 15 
volts).  Also not shown on the schematic is a 0.47 uF cap around the 14.9 
kilo-ohm resistor.  I think I was trying to limit the bandwidth to around 15 
hertz.

Also the resistor going between the op amp and the limiting diodes was marked 
10K, its 20K.  The diodes are 1N4148.  Corrected drawing attached.

This is what happens to time nuts who can only play on the weekend and stay up 
all nightand my employer just thinks I party too hard.for Monday 
mornings.



Brian KD4FM



Bruce Griffiths wrote:
 

The LT1037 is shown with a gain of ~1690x, if this amplifier is used to amplify 
the beat frequency signal, it will saturate.
Opamp recovery from saturation is poorly documented and may be very slow.
It would be better to use some diodes in the amplifier feedback network to 
limit the large signal gain to 5x (so that the LT1037 remains stable as it 
isn't unity gain stable).
This will ensure a somewhat faster recovery from overload as the LT1037 then 
avoids saturation and the opamp input stage remains in the linear region.

Bruce

Bob Camp wrote:
   

Hi

Assuming that the junction of the back to back diodes goes trough a chunk of 
coax to get to the counter:

You are forming a low pass filter with the 10K resistor and the coax 
capacitance. The LT1037 is quite happy driving a 600 ohm load. You could easily 
drop the impedance at that point below 300 ohms. That should give you a faster 
edge into the counter.

You also should check the slew rate performance of the 1037. You don't want the 
op amp to be slew rate limited.

Bob


On Feb 27, 2010, at 12:41 PM, Brian Kirby wrote:


 

I am in the process of designing a DMTD system.  As an experiment to do basic 
measurements on the chosen mixer, I used a capacitor (0.01 uF) in series to 
ground with a 47 ohm metal film resistor.  Where the capacitor and resistor 
meets, another resistor is attached (390 ohms) that goes to ground.  The idea 
is to provide a 50 ohm termination at 20 Mhz and a lighter termination at audio 
frequencies.  I seen this is a NBS note and I can say, its a starting point for 
my experiments.

This (my) system is designed for 10 Mhz, using a 10 hertz beat.  A schematic is 
attached of what I am experimenting with at the moment.  A HP5370B is the 
recording instrument.  The noise floor from 1 days observations show  2x10-11 
at 0.1 seconds, 2x10-12 at 1 sec, 5x10-13 at 10 sec, 6x10-14 at 100 sec,

Re: [time-nuts] Achieving maximum performance when driving 5370A/Binputs

2010-02-28 Thread Rex


Don Latham wrote:
I've fixed shafts like this carefully with plastic swizzle sticks and 
super glue. Did I say carefully? a little dab'll do ya...

Don



It is a tricky business. The 5370A I got a while back, had what was left 
of the shaft glued into the bushing by an earlier repair attempt. The 
shaft plastic is not one that fuses easily (polyethylene maybe). I 
managed to repair mine, but the process I used took many hours and I 
wouldn't recommend it. I removed the pot and was able to disassemble it. 
I then drilled a very small hole down the center axis of the shaft and 
used a section of very small screw rod to reinforce the joint. That 
combined with glue has held up so far. For the repair, I made a tool to 
align the drill to the shaft. The pot is not intended to come apart and 
is small. An evil job.


I thought the 5370B had gone to a steel-shaft version of these pots. 
Maybe it depends on vintage.




- Original Message - From: Mark Sims hol...@hotmail.com
To: time-nuts@febo.com
Sent: Saturday, February 27, 2010 10:10 PM
Subject: [time-nuts] Achieving maximum performance when driving 
5370A/Binputs





If it's the one that I think it is...  look closely at the photo.  
The shafts on two of the pots are sheared off at the panel.   These 
are the display update control and the external arming level 
control.   These were custom HP pots with a funky (and delicate)  
switch.  They had brittle plastic shafts.Gee,  how do I know 
this...  could it be that a large percentage of the 5370's for sale 
have the same defect?


Luckily those controls are not too critical for normal operation.  
They can be replaced with regular (switchless) pots if you jumper the 
switch pads correctly.  Be careful,  there were two different layouts 
to those controls.



--
So exactly how did you know that I bought a (cheap) 5370B a few hours 
ago on the e-place





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Re: [time-nuts] My DIY frequency counter and a request for help

2010-02-28 Thread Magnus Danielson


Gerard,

Gerard PG5G wrote:

   Hello all,
   First post here, so I'll start with a quick introduction. I trained as
   an electronic engineer but don't work in that field any more, which has
   given me the appetite back to do some electronic engineering as a
   hobby. I have been a licensed ham for over 25 years (more than 60% of
   my life I realised the other day) and used to be rather active on HF as
   PA3DQW. At the moment I live in the UK where I am licensed as M0AIU.
   I recently designed and build a frequency counter and I need some help
   with verifying its performance. I believe it gives me 11 digits in 1
   second. I say believe because I have not got the hardware to verify
   this. At the moment my assumption is based on calculations and limited
   testing with the equipment available to me.
   My counter is a continuous time stamping reciprocal counter. I
   implemented this as a USB powered device, with the hardware taking the
   time stamps and sending it over USB to a windows PC. Some software
   written in C++ takes care of analysing the data.
   The hardware takes 5000 time stamps per second using a high speed TDC.
   The hardware is a single PCB measuring about 50 by 80 mm. it requires
   an external 10MHz reference and apart from using this as the time base
   it also uses this for self-calibration of the TDC. The unit requires no
   further calibration.
   The PC software takes these time stamps and the associated counts and
   uses regression to calculate the slope. This slope represents the
   frequency of the input signal. I am sure people on here are familiar
   with the counters made by Pendulum, and I have to confess that their
   marketing material was helpful in putting this thing together.
   Since the hardware is true zero dead time, the final capabilities of
   this counter are determined by software. At the moment I can
   simultaneously display the input at multiple gate times (see the
   attached screen shot). For gate times over 1 second I have the option
   to use overlapping gates, so that the display gets updated every
   second.
   Because there is no dead time I can also calculate Allan Deviation. The
   two displays at the bottom of the page show both normal and overlapping
   Allan deviation at tau=10s. I am still working on the software to do
   this at multiple tau in real time and display it as a graph and a
   table.
   So, after this lengthy introduction here is my request for some
   assistance. Is there somebody on the list who can assist me in
   verifying the performance of this frequency counter? Ideally somebody
   with access to two highly stable and known frequency sources. I can
   send the hardware by mail, but if there happens to be somebody with
   this kind of gear not too far from where I am (50 north of London) I
   will travel. In exchange you get to keep the hardware and will be
   supplied with whatever software I come up with.


Would you consider to disclose your architecture somewhat more?

Could you output time and event values from the time-stamping?
Would allow us to do some off-line processing independently.

Could you try different frequencies/amplitudes (would be good for 
establishing the slew-rate dependency, i.e. internal noise). Measure 
period jitter and plot for different slew-rates (frequency and 
amplitude), use shortest tau possible.


Could you hook up the reference clock with different lengths of coax 
cables. This would assist in measure the background noise and the 
different lengths of cables would allow some indication of interpolator 
non-linearity and input cross-talk.


As has already been discussed, software can do a lot for improving the 
reading, but one needs to be careful in details or else completely 
different measures results and they does not behave correctly. ADEV and 
friends wants the raw time-samples. Frequency or period estimation 
benefits from improved estimators, but then that is not useful for ADEV 
and friends, so it is a dead end for further processing except 
presentation level.


I think I have a fairly good setup including bunches of rock, gas and 
air clocks alongside a fair set of counters, so I could probably do some 
testing, but I am located over in Sweden. However, starting your verify 
exercise with a fellow time-nut excursion yourself should be a nice 
exercise that I recommend regardless. You should have several 
friendly-minded in UK.


Cheers,
Magnus

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Re: [time-nuts] DMTD Mixer Terminations

Hi

Here's some data:

The setup is very simple:

Two oscillators at 10 MHz driving common base / 50 ohm output buffers. The 
buffers ensure that the source impedance is really 50 ohms. One puts out 9.3 
dbm the other 9.5 dbm. They can be tuned for a beat note in the 0 to 100 Hz 
range. 

The basic mixer termination filter is a pair cascaded / identical L networks. 
Both have 10 uh in the series leg and 0.047 uf to ground in the shunt leg. The 
audio end of the filter hooks straight into a digitizing scope. 

The termination options for the mixer are:

1) inductive - just running into the 10 uh of the first L network.
2) 50 ohms - drop a 57 ohm in series with 0.047 from the mixer output to ground
3) Capacitive - 0.047 uf  to ground at the mixer output. 

The data is computed from the time to cross the center 50% of the output 
waveform. If the output is 1V p-p then the data would cover the range -.25 to 
+.25 volts. I've normalized it to volts / cycle. Divide by 2* pi if you want 
to get volts / radian. 


mixer   50 ohms inductive   capacitive

ZAD-3   3.512.969.98
RPD-1 #117.77   10.50   18.85
RPD-1 #217.40   10.058  18.53
10514A #1   5.796   4.396   10.31
10514A #2   5.826   4.406   10.33
10534A  5.402   4.078   10.88
ZP3-MH  8.065.8111.28
ZAD-1H  7.735.939.38

Since not everybody has memorized mixer catalogs:

ZAD-3   typical minicircuits 7 to 10 dbm mixer
RPD-1   500 ohm output phase detector (50 ohms is the wrong 
termination for it)
10514, 10534 HP products from a ways back
ZP3-MH  a 13 dbm class mixer, 9 dbm should be under driving it
ZAD-1H  a 17 dbm class mixer, should be 8 db under driven.

Bottom line - Capacitive termination helps some parts more than others. The 
RPD-1 does not get a real big boost, but the ZAD-1 certainly does. There's no 
real way to know what it's going to do without checking your mixer under your 
conditions. 

A few other notes:

1) The measurement technique slightly under states the slope for the 50 ohm 
case. Since the beat note is approximately a sine wave in all cases, the true 
slope at zero is a bit higher than this technique indicates.

2) The Inductive termination gives the widest linear region. The output is very 
nearly an ideal triangle wave. It would make the best wide range phase 
detector. 

3) The terminations are not precise, but they are identical in all cases. A 
more purely inductive load could be constructed. The parts are just what I had 
lying around.

4) No strange bumps or peaks were detected in the beat notes of any of the 
mixers. Never seen one, regardless of what NIST says they have seen.

5) Eventually I'll go back and check the RPD's with 500 ohms. I stuck with 50 
simply to keep everything as same same as I could.

6) Sweeping the beat note from 100 Hz to 1 Hz showed no change in the output 
amplitude. 

7) Contrary to my previous post the peak-peak output voltages are within 10% 
for all terminations. Slope and peak to peak are different things.

8) All mixers are running into essentially an open circuit load at audio. The 
scope input is  1 M ohm and the capacitive reactances are  100 K ohms. 

9) No attempt was made to set up directional couplers and figure out what the 
real input to the mixers actually is.  Ditto on playing with series resistors 
to improve the match. 

So there it is. Anybody else got some data to compare to. 

Bob

On Feb 28, 2010, at 3:53 PM, Bruce Griffiths wrote:

 My simulations indicate that terminating the Mixer IF port in an RF short 
 (with both RF and LO ports saturated) increases the beat frequency zero 
 crossing slope by more than a factor of 2 (exact value depends on mixer 
 component characteristics) but doesnt significantly increase the beat 
 frequency amplitude over that with a high value resistive termination. To 
 achieve this the IF port termination impedance needs to be high at the beat 
 frequency and its significant harmonics. The value above which the impedance 
 is considered high depends on mixer details such as transformer turns ratio, 
 RF source impedance, diode characteristics and RF input levels, etc.
 
 Bruce
 
 Bob Camp wrote:
 Hi
 
 Putting The C on the feedback R in a positive gain setup is only going to 
 take the roll off gain down to 1. Doing the same with an inverting amp or 
 using a series R / cap to ground will drop the gain a lot more in the roll 
 off region.
 
 I would worry about any resistor that's marked as 10K and reads 20K. It's 
 likely noisy.
 
 A typical DBM has a loss of 5 to 7 db when not in compression. With a +7  to 
 +10 dbm  drive that should give you an

Re: [time-nuts] DMTD Mixer Terminations

Hi

Left out:

All the data was taken with a beat note of roughly 10.2 Hz

Bob


On Feb 28, 2010, at 8:11 PM, Bob Camp wrote:

 Hi
 
 Here's some data:
 
 The setup is very simple:
 
 Two oscillators at 10 MHz driving common base / 50 ohm output buffers. The 
 buffers ensure that the source impedance is really 50 ohms. One puts out 9.3 
 dbm the other 9.5 dbm. They can be tuned for a beat note in the 0 to 100 Hz 
 range. 
 
 The basic mixer termination filter is a pair cascaded / identical L networks. 
 Both have 10 uh in the series leg and 0.047 uf to ground in the shunt leg. 
 The audio end of the filter hooks straight into a digitizing scope. 
 
 The termination options for the mixer are:
 
 1) inductive - just running into the 10 uh of the first L network.
 2) 50 ohms - drop a 57 ohm in series with 0.047 from the mixer output to 
 ground
 3) Capacitive - 0.047 uf  to ground at the mixer output. 
 
 The data is computed from the time to cross the center 50% of the output 
 waveform. If the output is 1V p-p then the data would cover the range -.25 to 
 +.25 volts. I've normalized it to volts / cycle. Divide by 2* pi if you 
 want to get volts / radian. 
 
 
 mixer 50 ohms inductive   capacitive
 
 ZAD-3 3.512.969.98
 RPD-1 #1  17.77   10.50   18.85
 RPD-1 #2  17.40   10.058  18.53
 10514A #1 5.796   4.396   10.31
 10514A #2 5.826   4.406   10.33
 10534A5.402   4.078   10.88
 ZP3-MH8.065.8111.28
 ZAD-1H7.735.939.38
 
 Since not everybody has memorized mixer catalogs:
 
 ZAD-3 typical minicircuits 7 to 10 dbm mixer
 RPD-1 500 ohm output phase detector (50 ohms is the wrong 
 termination for it)
 10514, 10534 HP products from a ways back
 ZP3-MHa 13 dbm class mixer, 9 dbm should be under driving it
 ZAD-1Ha 17 dbm class mixer, should be 8 db under driven.
 
 Bottom line - Capacitive termination helps some parts more than others. The 
 RPD-1 does not get a real big boost, but the ZAD-1 certainly does. There's no 
 real way to know what it's going to do without checking your mixer under your 
 conditions. 
 
 A few other notes:
 
 1) The measurement technique slightly under states the slope for the 50 ohm 
 case. Since the beat note is approximately a sine wave in all cases, the true 
 slope at zero is a bit higher than this technique indicates.
 
 2) The Inductive termination gives the widest linear region. The output is 
 very nearly an ideal triangle wave. It would make the best wide range phase 
 detector. 
 
 3) The terminations are not precise, but they are identical in all cases. A 
 more purely inductive load could be constructed. The parts are just what I 
 had lying around.
 
 4) No strange bumps or peaks were detected in the beat notes of any of the 
 mixers. Never seen one, regardless of what NIST says they have seen.
 
 5) Eventually I'll go back and check the RPD's with 500 ohms. I stuck with 50 
 simply to keep everything as same same as I could.
 
 6) Sweeping the beat note from 100 Hz to 1 Hz showed no change in the output 
 amplitude. 
 
 7) Contrary to my previous post the peak-peak output voltages are within 10% 
 for all terminations. Slope and peak to peak are different things.
 
 8) All mixers are running into essentially an open circuit load at audio. The 
 scope input is  1 M ohm and the capacitive reactances are  100 K ohms. 
 
 9) No attempt was made to set up directional couplers and figure out what the 
 real input to the mixers actually is.  Ditto on playing with series 
 resistors to improve the match. 
 
 So there it is. Anybody else got some data to compare to. 
 
 Bob
 
 On Feb 28, 2010, at 3:53 PM, Bruce Griffiths wrote:
 
 My simulations indicate that terminating the Mixer IF port in an RF short 
 (with both RF and LO ports saturated) increases the beat frequency zero 
 crossing slope by more than a factor of 2 (exact value depends on mixer 
 component characteristics) but doesnt significantly increase the beat 
 frequency amplitude over that with a high value resistive termination. To 
 achieve this the IF port termination impedance needs to be high at the beat 
 frequency and its significant harmonics. The value above which the impedance 
 is considered high depends on mixer details such as transformer turns ratio, 
 RF source impedance, diode characteristics and RF input levels, etc.
 
 Bruce
 
 Bob Camp wrote:
 Hi
 
 Putting The C on the feedback R in a positive gain setup is only going to 
 take the roll off gain down to 1. Doing the same with an inverting amp or 
 using a series R / cap to ground will drop the gain a lot more

[time-nuts] Rock, gas, and air

2010-02-28 Thread Bill Hawkins

Rock I take to be crystal. How about gas and air?

Bill Hawkins 

-Original Message-
From: Magnus Danielson
Sent: Sunday, February 28, 2010 5:15 PM
To: p...@b737.co.uk; Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] My DIY frequency counter and a request for help

--%--

I think I have a fairly good setup including bunches of rock, gas and 
air clocks alongside a fair set of counters, so I could probably do some 
testing, but I am located over in Sweden. 

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Re: [time-nuts] DMTD Mixer Terminations

The results for the RPD-1's are about what I expected: there's little 
difference in slope between either a 50 ohm +47nF termination or a 47nF 
termination.
The slopes are about 6.5x greater than the values given by Minicircuits. 
(8mv/degree = 2.88V/cycle). I assume that they use 500 ohms connected 
directly to ground not via a capacitor.
So there's something in NISTs claims of improved slope at least for the 
RPD-1.
I suspect that NISTs original 50 ohm terminations were actually 50 ohms 
direct to ground not via a capacitor.
Using a series capacitor increases the termination impedance at the beat 
frequency substantially over that when the resistor is connected 
directly to ground.


Since its is also claimed by NIST and others that reactive termination 
reduces the noise, one also needs to measure the output noise spectral 
density for the various IF port terminations.


Bruce

Bob Camp wrote:

Hi

Here's some data:

The setup is very simple:

Two oscillators at 10 MHz driving common base / 50 ohm output buffers. The 
buffers ensure that the source impedance is really 50 ohms. One puts out 9.3 
dbm the other 9.5 dbm. They can be tuned for a beat note in the 0 to 100 Hz 
range.

The basic mixer termination filter is a pair cascaded / identical L networks. Both have 
10 uh in the series leg and 0.047 uf to ground in the shunt leg. The audio 
end of the filter hooks straight into a digitizing scope.

The termination options for the mixer are:

1) inductive - just running into the 10 uh of the first L network.
2) 50 ohms - drop a 57 ohm in series with 0.047 from the mixer output to ground
3) Capacitive - 0.047 uf  to ground at the mixer output.

The data is computed from the time to cross the center 50% of the output waveform. If the 
output is 1V p-p then the data would cover the range -.25 to +.25 volts. I've normalized 
it to volts / cycle. Divide by 2* pi if you want to get volts / radian.


mixer   50 ohms inductive   capacitive

ZAD-3   3.512.969.98
RPD-1 #117.77   10.50   18.85
RPD-1 #217.40   10.058  18.53
10514A #1   5.796   4.396   10.31
10514A #2   5.826   4.406   10.33
10534A  5.402   4.078   10.88
ZP3-MH  8.065.8111.28
ZAD-1H  7.735.939.38

Since not everybody has memorized mixer catalogs:

ZAD-3   typical minicircuits 7 to 10 dbm mixer
RPD-1   500 ohm output phase detector (50 ohms is the wrong 
termination for it)
10514, 10534 HP products from a ways back
ZP3-MH  a 13 dbm class mixer, 9 dbm should be under driving it
ZAD-1H  a 17 dbm class mixer, should be 8 db under driven.

Bottom line - Capacitive termination helps some parts more than others. The 
RPD-1 does not get a real big boost, but the ZAD-1 certainly does. There's no 
real way to know what it's going to do without checking your mixer under your 
conditions.

A few other notes:

1) The measurement technique slightly under states the slope for the 50 ohm 
case. Since the beat note is approximately a sine wave in all cases, the true 
slope at zero is a bit higher than this technique indicates.

2) The Inductive termination gives the widest linear region. The output is very nearly an 
ideal triangle wave. It would make the best wide range phase detector.

3) The terminations are not precise, but they are identical in all cases. A 
more purely inductive load could be constructed. The parts are just what I had 
lying around.

4) No strange bumps or peaks were detected in the beat notes of any of the 
mixers. Never seen one, regardless of what NIST says they have seen.

5) Eventually I'll go back and check the RPD's with 500 ohms. I stuck with 50 simply to 
keep everything as same same as I could.

6) Sweeping the beat note from 100 Hz to 1 Hz showed no change in the output 
amplitude.

7) Contrary to my previous post the peak-peak output voltages are within 10% 
for all terminations. Slope and peak to peak are different things.

8) All mixers are running into essentially an open circuit load at audio. The scope 
input is  1 M ohm and the capacitive reactances are100 K ohms.

9) No attempt was made to set up directional couplers and figure out what the 
real input to the mixers actually is.  Ditto on playing with series resistors 
to improve the match.

So there it is. Anybody else got some data to compare to.

Bob

On Feb 28, 2010, at 3:53 PM, Bruce Griffiths wrote:

   

My simulations indicate that terminating the Mixer IF port in an RF short (with 
both RF and LO ports saturated) increases the beat frequency zero crossing 
slope by more than a factor of 2 (exact value depends on mixer component 
characteristics) but doesnt

Re: [time-nuts] Rock, gas, and air


Bill Hawkins wrote:

Rock I take to be crystal. How about gas and air?

Bill Hawkins

-Original Message-
From: Magnus Danielson
Sent: Sunday, February 28, 2010 5:15 PM
To: p...@b737.co.uk; Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] My DIY frequency counter and a request for help

--%--

I think I have a fairly good setup including bunches of rock, gas and
air clocks alongside a fair set of counters, so I could probably do some
testing, but I am located over in Sweden.


   

Gas = rubidium vapour??

Bruce


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Re: [time-nuts] Rock, gas, and air

2010-02-28 Thread Bill Hawkins

Whack! (sound of hand hitting forehead)

Gas must be Ru and Cs.

How do you run your pneumatic clocks?

Bill Hawkins
 

-Original Message-
From: Bill Hawkins [mailto:b...@iaxs.net] 
Sent: Sunday, February 28, 2010 7:34 PM
To: 'Discussion of precise time and frequency measurement';
'p...@b737.co.uk'
Subject: Rock, gas, and air

Rock I take to be crystal. How about gas and air?

Bill Hawkins 

-Original Message-
From: Magnus Danielson
Sent: Sunday, February 28, 2010 5:15 PM
To: p...@b737.co.uk; Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] My DIY frequency counter and a request for help

--%--

I think I have a fairly good setup including bunches of rock, gas and 
air clocks alongside a fair set of counters, so I could probably do some 
testing, but I am located over in Sweden. 


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Re: [time-nuts] Rock, gas, and air

2010-02-28 Thread Stanley Reynolds

A while back we had a thread about Paris and a network of air synced clocks ?

Stanley

- Original Message 
From: Bruce Griffiths bruce.griffi...@xtra.co.nz
To: Discussion of precise time and frequency measurement time-nuts@febo.com
Sent: Sun, February 28, 2010 7:41:20 PM
Subject: Re: [time-nuts] Rock, gas, and air

Bill Hawkins wrote:
 Rock I take to be crystal. How about gas and air?

 Bill Hawkins

 -Original Message-
 From: Magnus Danielson
 Sent: Sunday, February 28, 2010 5:15 PM
 To: p...@b737.co.uk; Discussion of precise time and frequency measurement
 Subject: Re: [time-nuts] My DIY frequency counter and a request for help

 --%--

 I think I have a fairly good setup including bunches of rock, gas and
 air clocks alongside a fair set of counters, so I could probably do some
 testing, but I am located over in Sweden.

Gas = rubidium vapour??

Bruce

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Re: [time-nuts] DMTD Mixer Terminations

Hi

The Minicircuits guys claim 800 to 1000 mv / radian. In my units that would be 
5 to 6.2 volts per cycle. I believe I'm getting ~ 3 X that mostly from the open 
circuit termination at audio. It's certainly something I could head back 
downstairs and check. 

The  10% increase in slope between resistive and capacitive termination has 
never really been enough with the RPD-1 to make it seem to be worth it. It's 
certainly worth it with a ZAD-3.

Bob


On Feb 28, 2010, at g8:39 PM, Bruce Griffiths wrote:

 The results for the RPD-1's are about what I expected: there's little 
 difference in slope between either a 50 ohm +47nF termination or a 47nF 
 termination.
 The slopes are about 6.5x greater than the values given by Minicircuits. 
 (8mv/degree = 2.88V/cycle). I assume that they use 500 ohms connected 
 directly to ground not via a capacitor.
 So there's something in NISTs claims of improved slope at least for the RPD-1.
 I suspect that NISTs original 50 ohm terminations were actually 50 ohms 
 direct to ground not via a capacitor.
 Using a series capacitor increases the termination impedance at the beat 
 frequency substantially over that when the resistor is connected directly to 
 ground.
 
 Since its is also claimed by NIST and others that reactive termination 
 reduces the noise, one also needs to measure the output noise spectral 
 density for the various IF port terminations.
 
 Bruce
 
 Bob Camp wrote:
 Hi
 
 Here's some data:
 
 The setup is very simple:
 
 Two oscillators at 10 MHz driving common base / 50 ohm output buffers. The 
 buffers ensure that the source impedance is really 50 ohms. One puts out 9.3 
 dbm the other 9.5 dbm. They can be tuned for a beat note in the 0 to 100 Hz 
 range.
 
 The basic mixer termination filter is a pair cascaded / identical L 
 networks. Both have 10 uh in the series leg and 0.047 uf to ground in the 
 shunt leg. The audio end of the filter hooks straight into a digitizing 
 scope.
 
 The termination options for the mixer are:
 
 1) inductive - just running into the 10 uh of the first L network.
 2) 50 ohms - drop a 57 ohm in series with 0.047 from the mixer output to 
 ground
 3) Capacitive - 0.047 uf  to ground at the mixer output.
 
 The data is computed from the time to cross the center 50% of the output 
 waveform. If the output is 1V p-p then the data would cover the range -.25 
 to +.25 volts. I've normalized it to volts / cycle. Divide by 2* pi if you 
 want to get volts / radian.
 
 
 mixer50 ohms inductive   
 capacitive
 
 ZAD-33.512.969.98
 RPD-1 #1 17.77   10.50   18.85
 RPD-1 #2 17.40   10.058  18.53
 10514A #15.796   4.396   10.31
 10514A #25.826   4.406   10.33
 10534A   5.402   4.078   10.88
 ZP3-MH   8.065.8111.28
 ZAD-1H   7.735.939.38
 
 Since not everybody has memorized mixer catalogs:
 
 ZAD-3typical minicircuits 7 to 10 dbm mixer
 RPD-1500 ohm output phase detector (50 ohms is the wrong 
 termination for it)
 10514, 10534 HP products from a ways back
 ZP3-MH   a 13 dbm class mixer, 9 dbm should be under driving it
 ZAD-1H   a 17 dbm class mixer, should be 8 db under driven.
 
 Bottom line - Capacitive termination helps some parts more than others. The 
 RPD-1 does not get a real big boost, but the ZAD-1 certainly does. There's 
 no real way to know what it's going to do without checking your mixer under 
 your conditions.
 
 A few other notes:
 
 1) The measurement technique slightly under states the slope for the 50 ohm 
 case. Since the beat note is approximately a sine wave in all cases, the 
 true slope at zero is a bit higher than this technique indicates.
 
 2) The Inductive termination gives the widest linear region. The output is 
 very nearly an ideal triangle wave. It would make the best wide range 
 phase detector.
 
 3) The terminations are not precise, but they are identical in all cases. A 
 more purely inductive load could be constructed. The parts are just what I 
 had lying around.
 
 4) No strange bumps or peaks were detected in the beat notes of any of the 
 mixers. Never seen one, regardless of what NIST says they have seen.
 
 5) Eventually I'll go back and check the RPD's with 500 ohms. I stuck with 
 50 simply to keep everything as same same as I could.
 
 6) Sweeping the beat note from 100 Hz to 1 Hz showed no change in the output 
 amplitude.
 
 7) Contrary to my previous post the peak-peak output voltages are within 10% 
 for all terminations. Slope and peak to peak are different things.
 
 8) All mixers are running into essentially an open circuit load at audio.

Re: [time-nuts] Rock, gas, and air

Hi

The winds in Sweden change directions in a *very* predictable fashion?

Bob


On Feb 28, 2010, at 8:50 PM, Stanley Reynolds wrote:

 A while back we had a thread about Paris and a network of air synced clocks ?
 
 Stanley
 
 
 
 - Original Message 
 From: Bruce Griffiths bruce.griffi...@xtra.co.nz
 To: Discussion of precise time and frequency measurement time-nuts@febo.com
 Sent: Sun, February 28, 2010 7:41:20 PM
 Subject: Re: [time-nuts] Rock, gas, and air
 
 Bill Hawkins wrote:
 Rock I take to be crystal. How about gas and air?
 
 Bill Hawkins
 
 -Original Message-
 From: Magnus Danielson
 Sent: Sunday, February 28, 2010 5:15 PM
 To: p...@b737.co.uk; Discussion of precise time and frequency measurement
 Subject: Re: [time-nuts] My DIY frequency counter and a request for help
 
 --%--
 
 I think I have a fairly good setup including bunches of rock, gas and
 air clocks alongside a fair set of counters, so I could probably do some
 testing, but I am located over in Sweden.
 
 
 
 Gas = rubidium vapour??
 
 Bruce
 
 
 ___
 time-nuts mailing list -- time-nuts@febo.com
 To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
 and follow the instructions there.
 
 
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 To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
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[time-nuts] Rock, gas, and air

2010-02-28 Thread Murray Greenman

Probably hot air...

Murray


-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of time-nuts-requ...@febo.com
Sent: Monday, 1 March 2010 2:56 p.m.
To: time-nuts@febo.com
Subject: time-nuts Digest, Vol 68, Issue 3

Send time-nuts mailing list submissions to
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Today's Topics:

   1. Re: Rock, gas, and air (Bruce Griffiths)
   2. Re: Rock, gas, and air (Bill Hawkins)
   3. Re: Rock, gas, and air (Stanley Reynolds)
   4. Re: DMTD Mixer Terminations (Bob Camp)
   5. Re: Rock, gas, and air (Bob Camp)


--

Message: 1
Date: Mon, 01 Mar 2010 14:41:20 +1300
From: Bruce Griffiths bruce.griffi...@xtra.co.nz
Subject: Re: [time-nuts] Rock, gas, and air
To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Message-ID: 4b8b1b40.8030...@xtra.co.nz
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

Bill Hawkins wrote:
 Rock I take to be crystal. How about gas and air?

 Bill Hawkins

 -Original Message-
 From: Magnus Danielson
 Sent: Sunday, February 28, 2010 5:15 PM
 To: p...@b737.co.uk; Discussion of precise time and frequency
measurement
 Subject: Re: [time-nuts] My DIY frequency counter and a request for
help

 --%--

 I think I have a fairly good setup including bunches of rock, gas and
 air clocks alongside a fair set of counters, so I could probably do
some
 testing, but I am located over in Sweden.



Gas = rubidium vapour??

Bruce




--

Message: 2
Date: Sun, 28 Feb 2010 19:47:55 -0600
From: Bill Hawkins b...@iaxs.net
Subject: Re: [time-nuts] Rock, gas, and air
To: 'Discussion of precise time and frequency measurement'
time-nuts@febo.com
Message-ID: 44f1d726cc5f42f99145fe8cb0f3f...@cyrus
Content-Type: text/plain;   charset=us-ascii

Whack! (sound of hand hitting forehead)

Gas must be Ru and Cs.

How do you run your pneumatic clocks?

Bill Hawkins
 

-Original Message-
From: Bill Hawkins [mailto:b...@iaxs.net] 
Sent: Sunday, February 28, 2010 7:34 PM
To: 'Discussion of precise time and frequency measurement';
'p...@b737.co.uk'
Subject: Rock, gas, and air

Rock I take to be crystal. How about gas and air?

Bill Hawkins 

-Original Message-
From: Magnus Danielson
Sent: Sunday, February 28, 2010 5:15 PM
To: p...@b737.co.uk; Discussion of precise time and frequency
measurement
Subject: Re: [time-nuts] My DIY frequency counter and a request for help

--%--

I think I have a fairly good setup including bunches of rock, gas and 
air clocks alongside a fair set of counters, so I could probably do some

testing, but I am located over in Sweden. 




--

Message: 3
Date: Sun, 28 Feb 2010 17:50:22 -0800 (PST)
From: Stanley Reynolds stanley_reyno...@yahoo.com
Subject: Re: [time-nuts] Rock, gas, and air
To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Message-ID: 380617.65743...@web30307.mail.mud.yahoo.com
Content-Type: text/plain; charset=iso-8859-1

A while back we had a thread about Paris and a network of air synced
clocks ?

Stanley



- Original Message 
From: Bruce Griffiths bruce.griffi...@xtra.co.nz
To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Sent: Sun, February 28, 2010 7:41:20 PM
Subject: Re: [time-nuts] Rock, gas, and air

Bill Hawkins wrote:
 Rock I take to be crystal. How about gas and air?

 Bill Hawkins

 -Original Message-
 From: Magnus Danielson
 Sent: Sunday, February 28, 2010 5:15 PM
 To: p...@b737.co.uk; Discussion of precise time and frequency
measurement
 Subject: Re: [time-nuts] My DIY frequency counter and a request for
help

 --%--

 I think I have a fairly good setup including bunches of rock, gas and
 air clocks alongside a fair set of counters, so I could probably do
some
 testing, but I am located over in Sweden.


? ? 
Gas = rubidium vapour??

Bruce


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and follow the instructions there.




--

Message: 4
Date: Sun, 28 Feb 2010 20:54:53 -0500
From: Bob Camp li...@rtty.us
Subject: Re: [time-nuts] DMTD Mixer Terminations
To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Message-ID: 43be29b2-dcb6-43e2-a23b-7ad1deb6b...@rtty.us
Content-Type: text/plain; charset=us-ascii

Hi

The

Re: [time-nuts] DMTD Mixer Terminations

Hi

Ok, RPD-1 #1 puts out 9.97 volts into a 500 ohm resistor to ground termination 
(no blocking capacitor). That's still well above the catalog spec. I'm running 
25% more voltage than their 7 dbm. That still does not fully explain what I'm 
seeing. 

The scope does indeed indicate 15 volts when I hook it to a 15 volt supply. 
Given the number of broken pieces of test gear I seem to own that was worth 
checking. ...

Bob


On Feb 28, 2010, at 8:54 PM, Bob Camp wrote:

 Hi
 
 The Minicircuits guys claim 800 to 1000 mv / radian. In my units that would 
 be 5 to 6.2 volts per cycle. I believe I'm getting ~ 3 X that mostly from the 
 open circuit termination at audio. It's certainly something I could head back 
 downstairs and check. 
 
 The  10% increase in slope between resistive and capacitive termination has 
 never really been enough with the RPD-1 to make it seem to be worth it. It's 
 certainly worth it with a ZAD-3.
 
 Bob
 
 
 On Feb 28, 2010, at g8:39 PM, Bruce Griffiths wrote:
 
 The results for the RPD-1's are about what I expected: there's little 
 difference in slope between either a 50 ohm +47nF termination or a 47nF 
 termination.
 The slopes are about 6.5x greater than the values given by Minicircuits. 
 (8mv/degree = 2.88V/cycle). I assume that they use 500 ohms connected 
 directly to ground not via a capacitor.
 So there's something in NISTs claims of improved slope at least for the 
 RPD-1.
 I suspect that NISTs original 50 ohm terminations were actually 50 ohms 
 direct to ground not via a capacitor.
 Using a series capacitor increases the termination impedance at the beat 
 frequency substantially over that when the resistor is connected directly to 
 ground.
 
 Since its is also claimed by NIST and others that reactive termination 
 reduces the noise, one also needs to measure the output noise spectral 
 density for the various IF port terminations.
 
 Bruce
 
 Bob Camp wrote:
 Hi
 
 Here's some data:
 
 The setup is very simple:
 
 Two oscillators at 10 MHz driving common base / 50 ohm output buffers. The 
 buffers ensure that the source impedance is really 50 ohms. One puts out 
 9.3 dbm the other 9.5 dbm. They can be tuned for a beat note in the 0 to 
 100 Hz range.
 
 The basic mixer termination filter is a pair cascaded / identical L 
 networks. Both have 10 uh in the series leg and 0.047 uf to ground in the 
 shunt leg. The audio end of the filter hooks straight into a digitizing 
 scope.
 
 The termination options for the mixer are:
 
 1) inductive - just running into the 10 uh of the first L network.
 2) 50 ohms - drop a 57 ohm in series with 0.047 from the mixer output to 
 ground
 3) Capacitive - 0.047 uf  to ground at the mixer output.
 
 The data is computed from the time to cross the center 50% of the output 
 waveform. If the output is 1V p-p then the data would cover the range -.25 
 to +.25 volts. I've normalized it to volts / cycle. Divide by 2* pi if 
 you want to get volts / radian.
 
 
 mixer   50 ohms inductive   
 capacitive
 
 ZAD-3   3.512.969.98
 RPD-1 #117.77   10.50   18.85
 RPD-1 #217.40   10.058  18.53
 10514A #1   5.796   4.396   10.31
 10514A #2   5.826   4.406   10.33
 10534A  5.402   4.078   10.88
 ZP3-MH  8.065.8111.28
 ZAD-1H  7.735.939.38
 
 Since not everybody has memorized mixer catalogs:
 
 ZAD-3   typical minicircuits 7 to 10 dbm mixer
 RPD-1   500 ohm output phase detector (50 ohms is the wrong 
 termination for it)
 10514, 10534 HP products from a ways back
 ZP3-MH  a 13 dbm class mixer, 9 dbm should be under driving it
 ZAD-1H  a 17 dbm class mixer, should be 8 db under driven.
 
 Bottom line - Capacitive termination helps some parts more than others. The 
 RPD-1 does not get a real big boost, but the ZAD-1 certainly does. There's 
 no real way to know what it's going to do without checking your mixer under 
 your conditions.
 
 A few other notes:
 
 1) The measurement technique slightly under states the slope for the 50 ohm 
 case. Since the beat note is approximately a sine wave in all cases, the 
 true slope at zero is a bit higher than this technique indicates.
 
 2) The Inductive termination gives the widest linear region. The output is 
 very nearly an ideal triangle wave. It would make the best wide range 
 phase detector.
 
 3) The terminations are not precise, but they are identical in all cases. A 
 more purely inductive load could be constructed. The parts are just what I 
 had lying around.
 
 4) No strange bumps or peaks were detected in the beat notes of any of the 
 mixers. Never seen one, regardless of what

Re: [time-nuts] Achieving maximum performance when driving 5370A/B inputs

2010-02-28 Thread Dave hartzell

Today I have been trying to drive a 5370B directly from a TADD-2, with
little luck (other HP freq counters seem to work OK).   I was about to ask
about it on this list, but noticed this thread.

I guess this could explain why I am getting erroneous, random readings?

Dave



On Sat, Feb 27, 2010 at 4:01 PM, Bruce Griffiths bruce.griffi...@xtra.co.nz
 wrote:

 The attached excerpts from the 5370A and 5370B manuals indicate that for
 best performance, that the common practice of driving the 5370A/B 1x inputs
 directly from a 5V CMOS logic signal is a bad idea.

 For the 5370A attenuating the 5V CMOS signal to a 1V swing with the
 threshold set to 0.5V is close to optimum.
 An input signal with limits of 0V and +1.4V with a trigger threshold of
 0.7V is the maximum usable (for high performance).
 An input signal with limits of 0V and +0.3V with a trigger threshold of
 0.15V is the minimum usable (for high performance).

 For the 5370A attenuating the 5V CMOS signal to a 2V swing with the
 threshold set to 1V is close to optimum.
 An input signal with limits of 0V and +3.5V with a trigger threshold of
 0.7V is the maximum usable (for high performance).
 An input signal with limits of 0V and +0.3V with a trigger threshold of
 0.15V is the minimum usable (for high performance).

 Bruce


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Re: [time-nuts] Achieving maximum performance when driving 5370A/Binputs

2010-02-28 Thread John Miles

What threshold are you using?  If you leave it set to preset/0 volts, you
may find that crosstalk between outputs on the TADD-2 cause false
triggering.  I usually use the divide-by-10 setting with the threshold set
to about 0.25V.

It also helps to remove the jumpers from any outputs on the TADD-2 you
aren't using.

-- john, KE5FX

 -Original Message-
 From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on
 Behalf Of Dave hartzell
 Sent: Sunday, February 28, 2010 7:28 PM
 To: Discussion of precise time and frequency measurement
 Subject: Re: [time-nuts] Achieving maximum performance when driving
 5370A/Binputs


 Today I have been trying to drive a 5370B directly from a TADD-2, with
 little luck (other HP freq counters seem to work OK).   I was about to ask
 about it on this list, but noticed this thread.

 I guess this could explain why I am getting erroneous, random readings?

 Dave



 On Sat, Feb 27, 2010 at 4:01 PM, Bruce Griffiths
 bruce.griffi...@xtra.co.nz
  wrote:

  The attached excerpts from the 5370A and 5370B manuals indicate that for
  best performance, that the common practice of driving the
 5370A/B 1x inputs
  directly from a 5V CMOS logic signal is a bad idea.
 
  For the 5370A attenuating the 5V CMOS signal to a 1V swing with the
  threshold set to 0.5V is close to optimum.
  An input signal with limits of 0V and +1.4V with a trigger threshold of
  0.7V is the maximum usable (for high performance).
  An input signal with limits of 0V and +0.3V with a trigger threshold of
  0.15V is the minimum usable (for high performance).
 
  For the 5370A attenuating the 5V CMOS signal to a 2V swing with the
  threshold set to 1V is close to optimum.
  An input signal with limits of 0V and +3.5V with a trigger threshold of
  0.7V is the maximum usable (for high performance).
  An input signal with limits of 0V and +0.3V with a trigger threshold of
  0.15V is the minimum usable (for high performance).
 
  Bruce
 
 
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Re: [time-nuts] Achieving maximum performance when driving 5370A/B inputs

The TADD-2 output drivers exhibit significant ringing and crosstalk due 
to ground and Vcc bounce.


To minimise crosstalk dedicate each 74AC04 output device to a single 
frequency and load.


Because of the ringing setting the trigger threshold is more critical 
than usual.


No damage occurs when driving the 5370A/B 1x inputs with 5V logic levels 
however various protection diodes will turn on and the preamp input 
stage becomes nonlinear.


Bruce

Dave hartzell wrote:

Today I have been trying to drive a 5370B directly from a TADD-2, with
little luck (other HP freq counters seem to work OK).   I was about to ask
about it on this list, but noticed this thread.

I guess this could explain why I am getting erroneous, random readings?

Dave



On Sat, Feb 27, 2010 at 4:01 PM, Bruce Griffithsbruce.griffi...@xtra.co.nz
   

wrote:
 
   

The attached excerpts from the 5370A and 5370B manuals indicate that for
best performance, that the common practice of driving the 5370A/B 1x inputs
directly from a 5V CMOS logic signal is a bad idea.

For the 5370A attenuating the 5V CMOS signal to a 1V swing with the
threshold set to 0.5V is close to optimum.
An input signal with limits of 0V and +1.4V with a trigger threshold of
0.7V is the maximum usable (for high performance).
An input signal with limits of 0V and +0.3V with a trigger threshold of
0.15V is the minimum usable (for high performance).

For the 5370A attenuating the 5V CMOS signal to a 2V swing with the
threshold set to 1V is close to optimum.
An input signal with limits of 0V and +3.5V with a trigger threshold of
0.7V is the maximum usable (for high performance).
An input signal with limits of 0V and +0.3V with a trigger threshold of
0.15V is the minimum usable (for high performance).

Bruce


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Re: [time-nuts] DMTD Mixer Terminations

Unless Minicircuits have made significant changes to the RPD-1 there has 
to be some kind of calibration error or an as yet poorly understood effect.

Did you try the load and filter shown in the attached application note?

Replicating Minicircuits measurements within 10% or so is probably 
necessary to correctly assess the effect of various termination networks.


Bruce

Bob Camp wrote:

Hi

Ok, RPD-1 #1 puts out 9.97 volts into a 500 ohm resistor to ground termination 
(no blocking capacitor). That's still well above the catalog spec. I'm running 
25% more voltage than their 7 dbm. That still does not fully explain what I'm 
seeing.

The scope does indeed indicate 15 volts when I hook it to a 15 volt supply. 
Given the number of broken pieces of test gear I seem to own that was worth 
checking. ...

Bob


On Feb 28, 2010, at 8:54 PM, Bob Camp wrote:

   

Hi

The Minicircuits guys claim 800 to 1000 mv / radian. In my units that would be 
5 to 6.2 volts per cycle. I believe I'm getting ~ 3 X that mostly from the open 
circuit termination at audio. It's certainly something I could head back 
downstairs and check.

The  10% increase in slope between resistive and capacitive termination has 
never really been enough with the RPD-1 to make it seem to be worth it. It's 
certainly worth it with a ZAD-3.

Bob


On Feb 28, 2010, at g8:39 PM, Bruce Griffiths wrote:

 

The results for the RPD-1's are about what I expected: there's little 
difference in slope between either a 50 ohm +47nF termination or a 47nF 
termination.
The slopes are about 6.5x greater than the values given by Minicircuits. 
(8mv/degree = 2.88V/cycle). I assume that they use 500 ohms connected directly 
to ground not via a capacitor.
So there's something in NISTs claims of improved slope at least for the RPD-1.
I suspect that NISTs original 50 ohm terminations were actually 50 ohms direct 
to ground not via a capacitor.
Using a series capacitor increases the termination impedance at the beat 
frequency substantially over that when the resistor is connected directly to 
ground.

Since its is also claimed by NIST and others that reactive termination reduces 
the noise, one also needs to measure the output noise spectral density for the 
various IF port terminations.

Bruce

Bob Camp wrote:
   

Hi

Here's some data:

The setup is very simple:

Two oscillators at 10 MHz driving common base / 50 ohm output buffers. The 
buffers ensure that the source impedance is really 50 ohms. One puts out 9.3 
dbm the other 9.5 dbm. They can be tuned for a beat note in the 0 to 100 Hz 
range.

The basic mixer termination filter is a pair cascaded / identical L networks. Both have 
10 uh in the series leg and 0.047 uf to ground in the shunt leg. The audio 
end of the filter hooks straight into a digitizing scope.

The termination options for the mixer are:

1) inductive - just running into the 10 uh of the first L network.
2) 50 ohms - drop a 57 ohm in series with 0.047 from the mixer output to ground
3) Capacitive - 0.047 uf  to ground at the mixer output.

The data is computed from the time to cross the center 50% of the output waveform. If the 
output is 1V p-p then the data would cover the range -.25 to +.25 volts. I've normalized 
it to volts / cycle. Divide by 2* pi if you want to get volts / radian.


mixer   50 ohms inductive   capacitive

ZAD-3   3.512.969.98
RPD-1 #117.77   10.50   18.85
RPD-1 #217.40   10.058  18.53
10514A #1   5.796   4.396   10.31
10514A #2   5.826   4.406   10.33
10534A  5.402   4.078   10.88
ZP3-MH  8.065.8111.28
ZAD-1H  7.735.939.38

Since not everybody has memorized mixer catalogs:

ZAD-3   typical minicircuits 7 to 10 dbm mixer
RPD-1   500 ohm output phase detector (50 ohms is the wrong 
termination for it)
10514, 10534 HP products from a ways back
ZP3-MH  a 13 dbm class mixer, 9 dbm should be under driving it
ZAD-1H  a 17 dbm class mixer, should be 8 db under driven.

Bottom line - Capacitive termination helps some parts more than others. The 
RPD-1 does not get a real big boost, but the ZAD-1 certainly does. There's no 
real way to know what it's going to do without checking your mixer under your 
conditions.

A few other notes:

1) The measurement technique slightly under states the slope for the 50 ohm 
case. Since the beat note is approximately a sine wave in all cases, the true 
slope at zero is a bit higher than this technique indicates.

2) The Inductive termination gives the widest linear region. The output is very nearly an 
ideal triangle wave. It would make the best wide range phase detector.

3) The

Re: [time-nuts] Achieving maximum performance when driving 5370A/Binputs

2010-02-28 Thread Dave hartzell

Thanks for the tips John.  Do you use the 50 ohm or 1M ohm settings with the
TADD-2?

Dave


On Sun, Feb 28, 2010 at 7:42 PM, John Miles jmi...@pop.net wrote:

 What threshold are you using?  If you leave it set to preset/0 volts, you
 may find that crosstalk between outputs on the TADD-2 cause false
 triggering.  I usually use the divide-by-10 setting with the threshold set
 to about 0.25V.

 It also helps to remove the jumpers from any outputs on the TADD-2 you
 aren't using.

 -- john, KE5FX

  -Original Message-
  From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on
  Behalf Of Dave hartzell
  Sent: Sunday, February 28, 2010 7:28 PM
  To: Discussion of precise time and frequency measurement
  Subject: Re: [time-nuts] Achieving maximum performance when driving
  5370A/Binputs
 
 
  Today I have been trying to drive a 5370B directly from a TADD-2, with
  little luck (other HP freq counters seem to work OK).   I was about to
 ask
  about it on this list, but noticed this thread.
 
  I guess this could explain why I am getting erroneous, random readings?
 
  Dave
 
 
 
  On Sat, Feb 27, 2010 at 4:01 PM, Bruce Griffiths
  bruce.griffi...@xtra.co.nz
   wrote:
 
   The attached excerpts from the 5370A and 5370B manuals indicate that
 for
   best performance, that the common practice of driving the
  5370A/B 1x inputs
   directly from a 5V CMOS logic signal is a bad idea.
  
   For the 5370A attenuating the 5V CMOS signal to a 1V swing with the
   threshold set to 0.5V is close to optimum.
   An input signal with limits of 0V and +1.4V with a trigger threshold of
   0.7V is the maximum usable (for high performance).
   An input signal with limits of 0V and +0.3V with a trigger threshold of
   0.15V is the minimum usable (for high performance).
  
   For the 5370A attenuating the 5V CMOS signal to a 2V swing with the
   threshold set to 1V is close to optimum.
   An input signal with limits of 0V and +3.5V with a trigger threshold of
   0.7V is the maximum usable (for high performance).
   An input signal with limits of 0V and +0.3V with a trigger threshold of
   0.15V is the minimum usable (for high performance).
  
   Bruce
  
  
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Re: [time-nuts] Achieving maximum performance when driving 5370A/B inputs

2010-02-28 Thread Dave hartzell

Thanks for the tips Bruce.

Is there a better version of the 74AC04?   It sounds like I should also
use an attenuator, perhaps 3 - 10 dB...

Dave


On Sun, Feb 28, 2010 at 7:43 PM, Bruce Griffiths bruce.griffi...@xtra.co.nz
 wrote:

 The TADD-2 output drivers exhibit significant ringing and crosstalk due to
 ground and Vcc bounce.

 To minimise crosstalk dedicate each 74AC04 output device to a single
 frequency and load.

 Because of the ringing setting the trigger threshold is more critical than
 usual.

 No damage occurs when driving the 5370A/B 1x inputs with 5V logic levels
 however various protection diodes will turn on and the preamp input stage
 becomes nonlinear.

 Bruce


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Re: [time-nuts] Achieving maximum performance when driving5370A/Binputs

2010-02-28 Thread John Miles

If you drive it from 50-ohm coax, you need to use the 50-ohm setting, or the
resulting reflections may cause trouble.  The 74AC04s in the TADD-2 are
happy enough driving 50 ohms, so that's the best way to go.

-- john, KE5FX

 -Original Message-
 From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on
 Behalf Of Dave hartzell
 Sent: Sunday, February 28, 2010 8:05 PM
 To: Discussion of precise time and frequency measurement
 Subject: Re: [time-nuts] Achieving maximum performance when
 driving5370A/Binputs


 Thanks for the tips John.  Do you use the 50 ohm or 1M ohm
 settings with the
 TADD-2?

 Dave


 On Sun, Feb 28, 2010 at 7:42 PM, John Miles jmi...@pop.net wrote:

  What threshold are you using?  If you leave it set to preset/0
 volts, you
  may find that crosstalk between outputs on the TADD-2 cause false
  triggering.  I usually use the divide-by-10 setting with the
 threshold set
  to about 0.25V.
 
  It also helps to remove the jumpers from any outputs on the TADD-2 you
  aren't using.
 
  -- john, KE5FX
 
   -Original Message-
   From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on
   Behalf Of Dave hartzell
   Sent: Sunday, February 28, 2010 7:28 PM
   To: Discussion of precise time and frequency measurement
   Subject: Re: [time-nuts] Achieving maximum performance when driving
   5370A/Binputs
  
  
   Today I have been trying to drive a 5370B directly from a TADD-2, with
   little luck (other HP freq counters seem to work OK).   I was about to
  ask
   about it on this list, but noticed this thread.
  
   I guess this could explain why I am getting erroneous, random
 readings?
  
   Dave
  
  
  
   On Sat, Feb 27, 2010 at 4:01 PM, Bruce Griffiths
   bruce.griffi...@xtra.co.nz
wrote:
  
The attached excerpts from the 5370A and 5370B manuals indicate that
  for
best performance, that the common practice of driving the
   5370A/B 1x inputs
directly from a 5V CMOS logic signal is a bad idea.
   
For the 5370A attenuating the 5V CMOS signal to a 1V swing with the
threshold set to 0.5V is close to optimum.
An input signal with limits of 0V and +1.4V with a trigger
 threshold of
0.7V is the maximum usable (for high performance).
An input signal with limits of 0V and +0.3V with a trigger
 threshold of
0.15V is the minimum usable (for high performance).
   
For the 5370A attenuating the 5V CMOS signal to a 2V swing with the
threshold set to 1V is close to optimum.
An input signal with limits of 0V and +3.5V with a trigger
 threshold of
0.7V is the maximum usable (for high performance).
An input signal with limits of 0V and +0.3V with a trigger
 threshold of
0.15V is the minimum usable (for high performance).
   
Bruce
   
   
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Re: [time-nuts] Achieving maximum performance when driving 5370A/B inputs