and frequency measurement
Subject: Re: [time-nuts] Achieving maximum performance when driving 5370A/B
inputs
Actually there are miniature twinax style connectors, for example:
http://www.amphenolrf.com/products/twinbnc.asp?N=0sid=4B8860805409E17F;
http://www.amphenolrf.com/products/twinbnc.asp?N=0sid
expensive.
D.
-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Bruce Griffiths
Sent: 28 February 2010 03:00
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Achieving maximum performance when driving
-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Bruce Griffiths
Sent: Saturday, February 27, 2010 9:56 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Achieving maximum performance when driving 5370A/B
inputs
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
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
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
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
You could substitute a 74AHC04 which has better control of ground and
Vcc bounce.
At least they are specified.
At least a 3dB attenuator with a 5370B.
at least 11dB with a 5370A.
Or just use the built in 20dB (10x) attenuator.
Bruce
Dave hartzell wrote:
Thanks for the tips Bruce.
Is there a
At 07:01 PM 2/27/2010, Bruce Griffiths wrote...
For the 5370A attenuating the 5V CMOS signal to a 1V...
For the 5370A attenuating the 5V CMOS signal to a 2V...
ITYM 5370B for the second part.
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Oops! a small correction (2nd paragraph):
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
Hi
Which *still* carefully avoids the issue of how .
Bob
On Feb 27, 2010, at 8:52 PM, Bruce Griffiths wrote:
Oops! a small correction (2nd paragraph):
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
Mike S wrote:
At 07:01 PM 2/27/2010, Bruce Griffiths wrote...
For the 5370A attenuating the 5V CMOS signal to a 1V...
For the 5370A attenuating the 5V CMOS signal to a 2V...
ITYM 5370B for the second part.
Yes, a result of cutting and pasting.
Bruce
1) One method with 5V CMOS is to add a resistive voltage divider at the
CMOS driver output with a 50 ohm output impedance at the tap that drives
the 5370A/B input.
2) If one has a 5V 50 ohm driver (eg Thunderbolt PPS output) use a 50
ohm attenuator at the 5370A/B input.
For a 5370A an
Hi
AC cmos will easily drive an L pad to match a 50 ohm cable at these levels.
That's true at either 3.3 or at 5.0 volts. There are a lot of cmos families out
there that beat AC for speed and match the output drive capability.
Bob
On Feb 27, 2010, at 9:12 PM, Bruce Griffiths wrote:
1) One
If one is feeling paranoid about ground loop noise (and wishes to avoid
transformers, optoisolators , or fibre optics), etc one could always use
an LVDS driver with a batter powered(?) LVDS to CMOS receiver/translator
right at the 5370A/B input BNC connector.
This may be useful for a DMTD
Hi
Gee, LVDS what an unusual approach :)
It would be nice if these instruments had a balanced input. Common mode noise
is indeed an issue in a lot of cases.
Of course wrapping the coax headed to the counter 10X around a fairly large
core can help things a bit.
Bob
On Feb 27, 2010, at
In general, what about the old National damn fast and super damn fast
LH0032 LH0033? I used to use a lot of those in my designs many years ago.
- Mike
Mike B. Feher, N4FS
89 Arnold Blvd.
Howell, NJ, 07731
732-886-5960
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Since the input amplifier and trigger circuit are located on a small
daughter board it wouldn't be too difficult to replace this with an LVDS
to CML stage.
The only remaining isue would be what input connector to use (twinax??,
SATA??).
Bruce
Bob Camp wrote:
Hi
Gee, LVDS what an unusual
Hi
I don't even have the counter and already we're butchering it
The big issue is suitable twin-ax connectors and cable. I have both, but they
are *big*. They never really made it into the world of miniature connectors and
miniature cable.
Shielded twisted pair would be another option.
Mike Feher wrote:
In general, what about the old National damn fast and super damn fast
LH0032 LH0033? I used to use a lot of those in my designs many years ago.
- Mike
Mike B. Feher, N4FS
89 Arnold Blvd.
Howell, NJ, 07731
732-886-5960
The LH0032 was a fast FET input opamp.
I presume you
Actually there are miniature twinax style connectors, for example:
http://www.amphenolrf.com/products/twinbnc.asp?N=0sid=4B8860805409E17F;
http://www.amphenolrf.com/products/twinbnc.asp?N=0sid=4B8860805409E17F;
Bruce
Bob Camp wrote:
Hi
I don't even have the counter and already we're
Hi
Sure never seen any of them on any gear in my junk pile.
I also never seen a customer ask for them as an output connector on an
oscillator. I wonder how common they actually are.
Bob
On Feb 27, 2010, at 9:59 PM, Bruce Griffiths wrote:
Actually there are miniature twinax style
You could look at a surplus F16 (probably wont fit in your garage
though) or similar STP was heavily used in MIL STD 1553 avionics buses.
Bruce
Bob Camp wrote:
Hi
Sure never seen any of them on any gear in my junk pile.
I also never seen a customer ask for them as an output connector on an
Hi
MIght have to move a few things in the shed to fin in an F16.
If they were used in quantity there aught to be cable and connectors out there.
The only reason I have the stuff I do is good old IBM and their approach to
networking back in the old days. It would be tough to properly drive an
R-390 or S/390?
The R-390 receiver (designed by Collins) is probably worth more today than an
S390. ;-)
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here is a two center pin type of BNC, presumably for a balanced twisted
pair or twin ax type cable.
The shape of the dielectric allows proper mechanical mating.
Stan, W1LE Cape Cod
Bob Camp wrote:
Hi
I don't even have the counter and already we're butchering it
The big issue is
, 2010 8:53:16 PM
Subject: Re: [time-nuts] Achieving maximum performance when driving 5370A/B
inputs
Hi
I don't even have the counter and already we're butchering it
The big issue is suitable twin-ax connectors and cable. I have both, but they
are *big*. They never really made
Mike Feher wrote:
In general, what about the old National damn fast and super damn fast
LH0032 LH0033? I used to use a lot of those in my designs many years ago.
- Mike
Gotta really decouple the power supplies on those puppies...
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Bob Camp wrote:
Hi
Sure never seen any of them on any gear in my junk pile.
I also never seen a customer ask for them as an output connector on an
oscillator. I wonder how common they actually are.
Bob
On Feb 27, 2010, at 9:59 PM, Bruce Griffiths wrote:
Actually there are miniature
These were used on some measuring instruments to provide a balance
'guarded' input.
The shield around the balanced conductors provided a ground between
the DUT and the measuring equipment that was not connected to the input.
IIRC this was for very low level signals.
73
Glenn
WB4UIV
At 10:06
found a picture of the Twin BNC here: http://drawings.amphenolrf.com/pdf/172.pdf
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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
performance when driving 5370A/B
inputs
If one is feeling paranoid about ground loop noise (and wishes to avoid
transformers, optoisolators , or fibre optics), etc one could always use
an LVDS driver with a batter powered(?) LVDS to CMOS receiver/translator
right at the 5370A/B input BNC connector
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