[time-nuts] time stamping counters

Magnus Danielson magnus at rubidium.dyndns.org
Sat Dec 29 18:49:38 EST 2007


From: "Pete" <peterawson at earthlink.net>
Subject: Re: [time-nuts] time stamping counters
Date: Sat, 29 Dec 2007 16:38:38 -0700
Message-ID: <00a201c84a73$f3fa22d0$0200a8c0 at BASE1>

Pete,

> I have attached a file of zero crossing times for
> a 1KHz zero crossing detector taken with my PM6681. This data is interesting because it
> records back-to-back events (zero dead-time)
> using the "picket fence" method published by
> Greenhall (in 1989). This back-to-back data allows me to calculate the Allan deviation
> correctly. I was also able to use the time-
> stamping results to insure the record included
> the correct number of points, with no gaps.

You should consider using TimeView. See below.

> I think the PM6691 has this capability built-in.
> Can you tell me if this is true?

This is true.

> If it is true, what is the maximum rate of capture for zero dead-
> time (TI) data?

8000 measures per second according to datasheet.

> How many data points can be captured in each record? 

To direct memory, 6100. Using TimeView you keep pumping data out of it.

First see:
http://www.pendulum-instruments.com/Assets/pd/pd_CNT-81_81R.pdf

Then go to:
http://www.pendulum-instruments.com/eng/htm/software.php

TimeView will do Allan Deviation for you, among other things.

The version you download works, but lack print and save.

Cheers,
Magnus



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