------------------------------
Message: 2
Date: Tue, 18 Feb 2014 15:37:45 -0400
From: Paul Berger <[email protected]>
To: [email protected]
Subject: Re: [time-nuts] FE-5680A sweep range setting
Message-ID: <[email protected]>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Hi,
I have a couple that look like the one in these pictures minus the the
little frequency control board.
http://www.flickr.com/photos/14336723@N08/sets/72157632394339366/
One of mine would not lock so what I did I looked at my other 5680A
which is the type referred to in the tip about C217 and looked at how it
is connected in relation to the crystal for the VCXO, which is very
close to C217. In the ones that I have with the stacked cards this
crystal is on the middle card with a little block of foam over it. Near
this crystal is a trim cap C245 that seems to be connected the same way
relative to the crystal and by adjusting it I was able to get mine to
lock, but did find the adjustment to be a bit twitchy and since it is on
the middle card, you need to remove the top one every time you want to
tweak it a bit.
The one that I have are marked with option 57 and instead of having a
flange around the edge like many of the telecom surplus ones it is
mounted on a piece of 1/4" aluminum plate. The top card has a PIC on
it and there is a RS232 level converter chip there but it looks like the
connection only go to the 5 pin connector next to the SP232ACT RS232
chip. This one does not require external +5V and in fact bring out the
10MHz on pin 4 where others seem to connect +5V. there does not appear
to be any PPS output either. These also have a cutout to expose the 15
pin connector that is on the base board in front of the physics package.
Paul.
On 2/17/14 11:03 PM, Simon Lyons wrote:
Hello everyone,
I have a 5680 which is failing to lock. My DDS frequency is 8388608Hz,
but it's sweeping between about 8388638 and 8388740. My unit has 3
levels of PCBs in the DDS/VCO corner and there is no trimcap labeled
C217. Does anyone know how to adjust the sweep center frequency on
this type of 'triple decker' unit?
Thanks,
=Simon=
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Message: 3
Date: Tue, 18 Feb 2014 12:34:00 -0800
From: "Chris Smith" <[email protected]>
To: <[email protected]>
Subject: Re: [time-nuts] HP 10811-60165 Double Oven Crystal Oscillator
Pin-Outs
Message-ID: <[email protected]>
Content-Type: text/plain; charset="iso-8859-1"
That pin-out sounds promising as this unit has
BLK-RED-BLK-ORG-YEL-GRN-BLU, which seems consistent with the one that
you provided. Did you source that from one of HP's various guides or
somewhere else?
CS
-----Original Message-----
From: [email protected] [mailto:[email protected]]On
Behalf Of Richard H McCorkle
Sent: Tuesday, February 18, 2014 11:07 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] HP 10811-60165 Double Oven Crystal Oscillator
Pin-Outs
Chris,
The 10811-60165 may be similar to the HP 10811-60158
that uses using the following pin-out:
1 - BRN Oscillator Return (Com)
2 - RED Oscillator Power (+12V)
3 - ORG Oven Monitor Return (Com)
4 - YEL Oven Monitor Output
5 - GRN Oven Power (+18-24V)
6 - BLU Oven Return (Com)
The following description is from the 10811 A/B Manual
where the recommended oven monitor circuit is shown:
The Oven Monitor Output is an indicator of oven warm-up.
At initial turn-on (warmup) the oven monitor will go to
approximately 1.5 volts below the oven power supply
voltage. After the oven cuts back, the output will drop
to approximately 3.5 volts (at 25?C). The output
impedance of this circuit is 10,000 ohms.
Richard
I've seen a pin-out for the outer-oven 6-position connector (2 heater
wires,
2 thermistor wires), but I've not found anything on the pin-out of the
other
6-position connector. Has anyone come across the pin-outs for the
10811-60165 connectors?
CS
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------------------------------
Message: 4
Date: Tue, 18 Feb 2014 18:00:17 -0500
From: Bob Camp <[email protected]>
To: Discussion of precise time and frequency measurement
<[email protected]>
Subject: Re: [time-nuts] strange behavior of 53230A or is the light
on, but nobody in?
Message-ID: <[email protected]>
Content-Type: text/plain; charset=windows-1252
Hi
Well at least this got me digging a little.
If you grab a copy of the 53230A spec sheet and look under the external
reference input, it?s pretty well described. It will accept 1, 5,10 MHz as an
external reference. It will lock over a 1 ppm range with the XO option and 0.1
ppm with the OCXO option. Based on that I?d guess they are still using the same
basic PLL approach as on the older counters (5335 era).
The ?Microsoft Windows inside? sticker on the back of the counter was a bit of
a surprise ?.
Bob
On Feb 18, 2014, at 11:51 AM, Tom Van Baak (lab) <[email protected]> wrote:
TomK,
If anyone has technical contacts deep within Agilent, let's see if this issue can be
resolved. I would have bought a 53230A when it came out a few years ago but my eval units
showed this clock noise problem. That plus the poor quality of the ref out made me think
the designers were cutting corners, or had little experience in metrology, or maybe they
thought this was "ok" for a bench instrument.
Otherwise it's a really nice counter; the first one from Agilent than can
actually do ADEV properly (since it is a time stamping counter).
I should dig out my old data and send it to you. Maybe as group we can help
them fix the problem.
/tvb
On Feb 18, 2014, at 12:10 AM, Tom Knox <[email protected]> wrote:
I have asked Agilent
if stock versions of the 53230A and 53132A switched the internal oscillator out
of circuit with an Ext Ref signal
applied. I thought
Agilent's engineer was intentionally vague but said the oscillators were
indeed switched out of circuit on the counter with Ext Ref signal applied.
These questions were related to several 53132A's I have seen configured with a
small board back near the Ext Ref input (OPT H01 I think) that appeared to
Switch the internal reference out of circuit. Agilent would not share
information on the option. My question to Agilent is why sell an option and be
unwilling to say what it does or how your stock unit functions?
Thomas Knox
From: [email protected]
Date: Mon, 17 Feb 2014 09:38:28 -1000
To: [email protected]
Subject: Re: [time-nuts] strange behavior of 53230A or is the light on, but
nobody in?
Bob,
I'm wondering if you (or any else) has measured the PLL performance of the
53230-series?
I agree it will "clean up the crud" but this assumes the ext ref is dirtier
than the internal osc.
What I found instead was that if you use a good external ref the PLL actually
makes it worse. This was very disappointing. The XO version of the counter
performed worse than the OCXO version even with a maser as the ext reference.
Did your reading of the schematic show a way to directly use the ext ref,
bypassing the noisy PLL?
The other thing I found was that the ref out signal was a very polluted copy of
the ref in.
/tvb (i5s)
On Feb 17, 2014, at 7:04 AM, Bob Camp <[email protected]> wrote:
Hi
If you dig into the schematics (when they supplied them ? ):
The external reference goes into a phase detector. It?s one of those digital
ones that can lock up to many inputs. You could feed 3.33333333 MHz in as a
standard input as well as 0.5, 1, 2.5, 5, and 10 MHz. The internal oscillator
(or an internal oscillator) is phase locked to the external input through a
fairly narrow analog loop. The idea is to clean up the crud on the standard
line.
With no external reference, the PLL drops out and you go back to what ever the
local reference is.
Yes there?s a little more to it than that and no the circuit is not exactly the
same on every counter HP ever made.
Bob
On Feb 17, 2014, at 7:55 AM, wb6bnq <[email protected]> wrote:
Hi Mike,
The most likely answer is when you select external time base for an input, it
disables the connection for the internal oscillator. The external input signal
is probably also routed straight to the reference output jack.
However, it would be good to read the manual, as they usually cover how those
connections work. Otherwise, perhaps someone that owns one could provide
further insight.
Bill....WB6BNQ
mike cook wrote:
Something that must be simple to explain, but that I can't get my head round.
I got a new 53230A.
When first using it, I measured my T-Bolt 10MHz using the internal 10MHz
timebase and it came up short of 10MHz, 9.999 998 5xx. I wasn't worried about
it as the counter only has a TCXO internal oscillator. So I fired up my PRS10
and after leaving that on for some time, connected it to Ext Ref. , changed to
the ext time base and measured again. This time 10.000.000.00x. Then I switched
the two references, measuring the PRS10 against the T-Bolt. Again I got 10MHz
down to the 11th digit.
All that looked good so I have been using it with either the PRS10 locked to
GPS, or the T-Bolt as the external time base.
After leaving it on (but not inactive) for a month, I did an Autocal. No
problem.
I was wondering if that would have changed the internal time base frequency,
but no, using that still gave similar figures to the above.
So at that point I decided to measure the Internal TB against my reference. So
I connected the Int. Ref. Out to channel 1, connected my PRS10 ref to Ext. Ref
In, selected the EXT time base and found that the count was 10MHz dead on?????
I don't get that at all.
in summary:
DUT against internal TB counts < 10MHz. To me that means that the internal
timebase is a bit fast. Is that assumption correct?
DUT against Ext.Ref counts 10MHz
Internal TB against Ext.Ref counts 10MHz. If my assumption above is
correct, the count should be greater than 10MHz, no?
Can anyone shed any light on that?
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------------------------------
Message: 5
Date: Tue, 18 Feb 2014 17:05:16 -0700
From: Tom Knox <[email protected]>
To: Time-Nuts <[email protected]>
Subject: Re: [time-nuts] strange behavior of 53230A or is the light
on, but nobody in?
Message-ID: <[email protected]>
Content-Type: text/plain; charset="Windows-1252"
Thanks Tom and Bob, I have been thinking of contacting Agilent for some time. I
think they are a great company with some good products, but there are a few
real blind spots in some current products. I also have seen in the past a
genuine interest in listening. I would be willing to approach them if I could
enlist your help in addressing potential changes to improve the product.
Thanks;
Thomas Knox
From: [email protected]
Date: Tue, 18 Feb 2014 18:00:17 -0500
To: [email protected]
Subject: Re: [time-nuts] strange behavior of 53230A or is the light on, but
nobody in?
Hi
Well at least this got me digging a little.
If you grab a copy of the 53230A spec sheet and look under the external
reference input, it?s pretty well described. It will accept 1, 5,10 MHz as an
external reference. It will lock over a 1 ppm range with the XO option and 0.1
ppm with the OCXO option. Based on that I?d guess they are still using the same
basic PLL approach as on the older counters (5335 era).
The ?Microsoft Windows inside? sticker on the back of the counter was a bit of
a surprise ?.
Bob
On Feb 18, 2014, at 11:51 AM, Tom Van Baak (lab) <[email protected]> wrote:
TomK,
If anyone has technical contacts deep within Agilent, let's see if this issue can be
resolved. I would have bought a 53230A when it came out a few years ago but my eval units
showed this clock noise problem. That plus the poor quality of the ref out made me think
the designers were cutting corners, or had little experience in metrology, or maybe they
thought this was "ok" for a bench instrument.
Otherwise it's a really nice counter; the first one from Agilent than can
actually do ADEV properly (since it is a time stamping counter).
I should dig out my old data and send it to you. Maybe as group we can help
them fix the problem.
/tvb
On Feb 18, 2014, at 12:10 AM, Tom Knox <[email protected]> wrote:
I have asked Agilent
if stock versions of the 53230A and 53132A switched the internal oscillator out
of circuit with an Ext Ref signal
applied. I thought
Agilent's engineer was intentionally vague but said the oscillators were
indeed switched out of circuit on the counter with Ext Ref signal applied.
These questions were related to several 53132A's I have seen configured with a
small board back near the Ext Ref input (OPT H01 I think) that appeared to
Switch the internal reference out of circuit. Agilent would not share
information on the option. My question to Agilent is why sell an option and be
unwilling to say what it does or how your stock unit functions?
Thomas Knox
From: [email protected]
Date: Mon, 17 Feb 2014 09:38:28 -1000
To: [email protected]
Subject: Re: [time-nuts] strange behavior of 53230A or is the light on, but
nobody in?
Bob,
I'm wondering if you (or any else) has measured the PLL performance of the
53230-series?
I agree it will "clean up the crud" but this assumes the ext ref is dirtier
than the internal osc.
What I found instead was that if you use a good external ref the PLL actually
makes it worse. This was very disappointing. The XO version of the counter
performed worse than the OCXO version even with a maser as the ext reference.
Did your reading of the schematic show a way to directly use the ext ref,
bypassing the noisy PLL?
The other thing I found was that the ref out signal was a very polluted copy of
the ref in.
/tvb (i5s)
On Feb 17, 2014, at 7:04 AM, Bob Camp <[email protected]> wrote:
Hi
If you dig into the schematics (when they supplied them ? ):
The external reference goes into a phase detector. It?s one of those digital
ones that can lock up to many inputs. You could feed 3.33333333 MHz in as a
standard input as well as 0.5, 1, 2.5, 5, and 10 MHz. The internal oscillator
(or an internal oscillator) is phase locked to the external input through a
fairly narrow analog loop. The idea is to clean up the crud on the standard
line.
With no external reference, the PLL drops out and you go back to what ever the
local reference is.
Yes there?s a little more to it than that and no the circuit is not exactly the
same on every counter HP ever made.
Bob
On Feb 17, 2014, at 7:55 AM, wb6bnq <[email protected]> wrote:
Hi Mike,
The most likely answer is when you select external time base for an input, it
disables the connection for the internal oscillator. The external input signal
is probably also routed straight to the reference output jack.
However, it would be good to read the manual, as they usually cover how those
connections work. Otherwise, perhaps someone that owns one could provide
further insight.
Bill....WB6BNQ
mike cook wrote:
Something that must be simple to explain, but that I can't get my head round.
I got a new 53230A.
When first using it, I measured my T-Bolt 10MHz using the internal 10MHz
timebase and it came up short of 10MHz, 9.999 998 5xx. I wasn't worried about
it as the counter only has a TCXO internal oscillator. So I fired up my PRS10
and after leaving that on for some time, connected it to Ext Ref. , changed to
the ext time base and measured again. This time 10.000.000.00x. Then I switched
the two references, measuring the PRS10 against the T-Bolt. Again I got 10MHz
down to the 11th digit.
All that looked good so I have been using it with either the PRS10 locked to
GPS, or the T-Bolt as the external time base.
After leaving it on (but not inactive) for a month, I did an Autocal. No
problem.
I was wondering if that would have changed the internal time base frequency,
but no, using that still gave similar figures to the above.
So at that point I decided to measure the Internal TB against my reference. So
I connected the Int. Ref. Out to channel 1, connected my PRS10 ref to Ext. Ref
In, selected the EXT time base and found that the count was 10MHz dead on?????
I don't get that at all.
in summary:
DUT against internal TB counts < 10MHz. To me that means that the internal
timebase is a bit fast. Is that assumption correct?
DUT against Ext.Ref counts 10MHz
Internal TB against Ext.Ref counts 10MHz. If my assumption above is
correct, the count should be greater than 10MHz, no?
Can anyone shed any light on that?
_______________________________________________
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To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
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End of time-nuts Digest, Vol 115, Issue 79
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