[time-nuts] [Fwd: Re: What is the best counter for a Time Nuts?]

Mike Monett XDE-L2G3 at myamail.com
Tue Oct 14 03:09:03 UTC 2008

hasweb at has.org.nz wrote:
>Mike Monett wrote:
>>   > So, assuming my known timebase is "bang on", I know  the frequency
>>   > of the unknown 10 MHz source to an accuracy of roughly 3e-10  or 3
>>   > parts in 10 billion.
>>   > To get  a  more precise measurement  of  the  frequency difference
>>   > between the two 10 MHz clocks, I supply the known 10 MHz  clock to
>>   > the Channel  A  input  of an HP  3575A  Gain-Phase  meter  and the
>>   > unknown 10  MHz  clock to the channel B  input  of  the Gain-Phase
>>   > meter.
>>   Another very  difficult instrument to find any data on.  The  best I
>>   could find shows it has an accuracy of ± 0.5 degree and resolution
>>   of 0.1 degree.
>Try the agilent website for the manuals not yet readily available
>For directions visit:
>www.hparchive.com <http://www.hparchive.com>
>There is a 3575A manual for downloading at the Agilent ftp link.
>If you read it you will find that the specified error with 10MHz  
>inputs is much larger: 10-20 degrees or so.

There is nothing in the hparchive site, and I don't have the Agilent ftp
site url.

Could you give a direct link to the 3575A manual?

The basic principle is sound. It should be very easy to make a simple PWM
circuit to measure phase accurately at 10MHz. You mentioned the same thing
earlier. Why not post the schematic so we can take a look?

Mike Monett

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