[time-nuts] Stanford Research SR620 Measurement Bias

Stan swperk at earthlink.net
Mon Sep 28 12:46:04 UTC 2009

Hi Ulrich,

Thanks for the insight! I tried manually adjusting the value of CalByte 50
(as per Magnus' suggestion), but it did not make the problem go away. There
is interaction between this adjustment and the CalByte 4 adjustment for
timebase accuracy, and when all was said and done, I didn't notice any
significant difference in the offset. 

Where in the manual does it describe the procedure to minimize the bias?
It's definitely not where I would have expected it to be!


Message: 1
Date: Mon, 28 Sep 2009 09:08:21 +0200
From: "Ulrich Bangert" <df6jb at ulrich-bangert.de>
Subject: Re: [time-nuts] Stanford Research SR620 Measurement Bias
To: "'Discussion of precise time and frequency measurement'"
	<time-nuts at febo.com>
Message-ID: <A4D0A2A6239B4798AB28E7193A646291 at athlon>
Content-Type: text/plain;	charset="us-ascii"


I own a SR620 as well and mine behaves the same (while with a different
number of "counts") so your's is surely not defective! My understanding a
few years ago when I acquired the counter was that this bias is not due to a
"adjustment" in the normal sense but to set a parameter in the counter's
eeprom to a correct value. Since this parameter is limited to a certain
precisison you can make some effort in minimizing this bias but you should
not expect to make it exactly zero. The manual explains how to do but you do
not find the procedure where you would have expected it.

Best regards
Ulrich Bangert

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