[time-nuts] Fast frequency counting question

Magnus Danielson magnus at rubidium.dyndns.org
Sun May 4 17:28:17 EDT 2008

From: "Murray Greenman" <murray at rakon.co.nz>
Subject: RE: [time-nuts] Fast frequency counting question
Date: Mon, 5 May 2008 09:01:38 +1200
Message-ID: <BE50C3A72EBA61449C804B2C8B4AE381D0551F at NEPTUNE.rakon.net>


> Thanks for your reply. Yes, I believe Leon has 30dB gain post mixer. He
> is using an FSS 1000E as his mixer. So, we don't think the problem is
> slew-rate limiting. Your suggestions for checking the performance with
> changes in level is a good one.

It should be standard practice... it is simple enought to rule it out.
A simple -6 dB pad away.

However, I am starting to consider that you are primarilly single-shot
resolution limited.

> This is an area of counting I've not considered before. We are working
> with the chip manufacturers, and they report the problem, which we would
> like to replicate. Personally I can't see it as an issue, but it has
> been raised, and we would like to understand how to measure it. The chip
> manufacturer has a high-speed A-D system and some method (unknown to us)
> for post-processing the data.
> I've suggested that Leon reply to you directly, as he has a better grip
> on what the problem and requirement is. I understand that the problem is
> relayed to warm-start TTFF performance in a GPS application.


I'd happy to help you out.


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