[time-nuts] Checking accuracy of Rubidium standards

wa1zms at att.net wa1zms at att.net
Sat Nov 8 19:58:35 EST 2008


This sounds to be a very similar method that my Tracor 895A uses.
Does that sound correct?

-Brian, WA1ZMS

-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com]On
Behalf Of Neville Michie
Sent: Saturday, November 08, 2008 5:09 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Checking accuracy of Rubidium standards


Hi,
I have a plan which involves the dividing down of the 10MHz of a GPSDO
and a rubidium (LPRO) to about 1MHz or 100kHZ and applying them to a
XOR or D latch to get a PWM signal that can be averaged for a strip  
chart recorder or
12 bit analogue data logger. The DC output gives a range of 5 volts  
for one
microsecond or 10 microseconds phase difference and folds back if  
this difference is exceeded.
The data from the datalogger is in a format that a spreadsheet can use.
With time and phase measurements I wonder how hard it is to get Allen  
variance.
I realise the PWM method requires a low pass filter and this will  
prevent short period
variances from being calculated.
cheers, Neville Michie
and follow the instructions there.




More information about the time-nuts mailing list