# [time-nuts] Looking for an HP K34-59991A Linear Phase Comparator

Jeroen Bastemeijer J.Bastemeijer at EWI.TUDelft.nl
Wed Dec 7 07:40:45 EST 2005

```Hi Robert,

It is an interesting problem. I have been looking in it for some time as
well. Planned to build such a phase-comparator myself.... no real
schematics yet, due to a lack of time :-(  (or maybe too many interests....)

To get a nice 50% duty cycle, you need more than just a D-Flip-Flop...
Probably you already figured that out. You need to synchronise the 50%
pulses with either the positive or the negative edge of your incoming
original signal. This would mean, that your frequency is at least
divided by a factor 4.

For the analog part:
You could consider using a limiter-like circuit, like the ones which are
used in FM-detector IC's. The input signal will be amplified till it
clips. The only interesting parameter is the zero-crossing, which could
be detected by a comparator. (Compare the signal to ground). However, a
slightly distorted (or noisy) sine wave will produce an error as well...
A distortion/noise in your inputsignal will always distort your
measurement. This makes me wonder if it really pays off to use very
fast/high-grade components. Did you do any calculations to estimate the
phase error (not the constant one), which will be introduced by certain
components?

A general question: what kind of signals do you want to compare/measure
the phase? 10 MHz, 10 kHz, 1 pps, .....???? Square, sine-wave???

Best regards, Jeroen PE1RGE

Robert Atkinson wrote:

>Hi Jeroen,
>Looks like a nice improvement. It deals mainly with the errors in the
>phase detector itself. The circuit still needs a 50% duty cycle
>squarewave logic level input. The problem of converting from a lower
>level sinewave input remanains. Using a differential line receiver IC
>with a transformer coupled input followed by a divide by 2 looks like
>the best bet. The Low Voltage Differential Signalling (LVDS) systems
>that are coming into use have spawned a range of high performance IC's.
>I've just got hold of some SN65LVDS048A quad receivers. Designed for
>200MHz and with 50ps channel to channel skew on a 2.7ns propagation
>delay, these should perform well. I've just got to do some testing. Need
>more time.....
>
>Robert G8RPI.
>
>
>-----Original Message-----
>From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
>Behalf Of Jeroen Bastemeijer
>Sent: 07 December 2005 09:52
>To: Discussion of precise time and frequency measurement
>Subject: Re: [time-nuts] Looking for an HP K34-59991A Linear Phase
>Comparator
>
>Dear All,
>
>I checked the patentsdatabase, there is another patent form Michael
>Fischer (US6,351,153) which claims to be less sensitive to temperature
>and supply voltage fluctuations. Interesting to read.
>Furthermore, when designing electronics, I always keep in mind the
>KISS-principle (Keep It Stupidly Simple). With carefull simple design,
>al lot of effects can be neglected or compensated for. More (expensive)
>electronics, doesn't mean a much better design. Usuallly more
>electronics invite noise and temperature influence instead of
>cancelling...
>
>Jeroen PE1RGE
>
>Robert Atkinson wrote:
>
>
>
>>Hi,
>>I've looked at building one of these and it's not quite so trivial to
>>duplicate. The speed of the logic is important, the original design
>>
>>
>used
>
>
>>ECL. High speed CMOS may be OK but how do you verify performance? The
>>original also used an unusual input circuit designed around a
>>discontinued line receiver IC. This is critical to performance, any
>>variation in threshold will appear as a phase error. I'm continuing to
>>prototype a new design and will let you know how I get on.
>>I've got a manual on PDF if you need it.
>>
>>Robert G8RPI.
>>
>>
>>-----Original Message-----
>>From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
>>Behalf Of Rick Karlquist
>>Sent: 06 December 2005 19:35
>>To: Discussion of precise time and frequency measurement
>>Cc: time-nuts at febo.com
>>Subject: Re: [time-nuts] Looking for an HP K34-59991A Linear Phase
>>Comparator
>>
>>It is trivial to build your own out of a couple of flip flops.
>>You can read Michael Fischer's patent on it (circa 1980).
>>
>>Rick Karlquist N6RK
>>
>>
>>NE8S wrote:
>>
>>
>>
>>
>>>Gentlemen:
>>>
>>>Happy Holidays to All Time, Frequency, and Phase Domainers.
>>>
>>>I am looking for an HP Linear Phase Comparator, Model K34-59991A. Does
>>>anyone have one to sell???
>>>
>>>Thanks in advance for checking and passing the word for me.
>>>
>>>Gar Ko
>>>NE8S
>>>
>>>
>>>bionucleonics at southwind.net
>>>_______________________________________________
>>>time-nuts mailing list
>>>time-nuts at febo.com
>>>https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>>>
>>>
>>>
>>>
>>>
>>>
>>
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--
Ing. Jeroen Bastemeijer

Delft University of Technology
Department of Electrical Engineering
Electronic Instrumentation Laboratory
Mekelweg 4, Room 13.090
2628 CD Delft
The Netherlands

Phone: +31.15.27.86542
Fax: +31.15.27.85755
E-mail: J.Bastemeijer at EWI.TUDelft.nl

```