[time-nuts] Once again about counter calibration

Brent Gordon time-nuts at adobe-labs.com
Fri Apr 24 22:36:55 EDT 2015

Just feed the PPS into the scope trigger on step 2.

The low repetition rate on the PPS would make this difficult on an 
analog scope; on a digital scope it is easy.  You can use any 
sub-harmonic that is less than or equal the counter reference frequency 
(10 MHz).


On 4/24/2015 3:45 PM, d0ct0r wrote:
> Hello,
> The input: HP 5386A which I would like to calibrate, Well warmed Tremble
> Thunderbolt (1PPS only), 10 Mhz Datum OCXO (unknown accuracy), Rigol
> 1101E Oscilloscope.
> The goal is to calibrate counter to read the Datum OCXO.
> ===========================
> Reading the manual for 5386A, there is simple schema for calibration:
> 1. Connect HP 5386A 10Mhz OUTPUT to Oscilloscope
> 2. Connect Frequency Standard to Ext. Trigger on Oscilloscope
> 3. Adjust the frequency on 5386A TCXO for minimum sideways movement of
> 10 Mhz signal
> However, my Trimble TB 10Mhz output is currently in use. I have only
> 1PPS signal available. The HP manual do not mention what exactly
> frequency needs to be on "Frequency Standard" connected to Ext. Trigger.
> Is there any method/option I could apply to calibrate HP counter ?
> Thanks !

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