[time-nuts] Ultra High Stability Time Base Options for 53132A

[Tom Van Baak]

Hi Rick,

It is our good fortune that some years ago Agilent/Keysight released the schematics to the 53131A/53132A counters:
http://literature.cdn.keysight.com/litweb/pdf/5989-6308EN.pdf

Have a look and see if you can recreate the details that you remembered.

I too have noticed on some tests that the counter seems to ruin the benefit of a good external timebase. This is even more true of the newer 53230-series counters. Maybe get rid of the PLL and use a int/ext toggle switch like the 70's.

So it would be nice if you or other circuit experts on the list could point out the flaw(s) -- I'm sure a couple of time nuts would even be willing to mod their 53132A boards based on some suggestions on what to try.

Thanks,
/tvb

----- Original Message ----- 
From: "Richard (Rick) Karlquist" <richard at karlquist.com>
To: "Discussion of precise time and frequency measurement" <time-nuts at febo.com>
Sent: Sunday, April 12, 2015 8:30 AM
Subject: Re: [time-nuts] Ultra High Stability Time Base Options for 53132A


> On 4/12/2015 1:03 AM, Adrian Godwin wrote:
>> What caused that degradation ? I'm interested in dos/don'ts for best use of
>> a 10811.
>>
> 
> I don't remember the details much after 25 years, but
> basically they have a distribution amplifier that
> allows for internal or external 10 MHz and what I
> remember is that I looked at the schematic and
> concluded that no one with a background in precision
> time and frequency would design it that way.  And
> it turned out that the person who designed it did
> not have any such background.  I vaguely require
> some measurement that had disappointing results that
> caused me to want to look at the schematic of it
> in the first place.
> 
> Rick