[time-nuts] Frequency counter questions
kb8tq at n1k.org
Mon Apr 24 19:31:18 EDT 2017
I believe what you are going to find is that the 3586 has an IF strip in it.
It does a heterodyne process to the IF center frequency and then indicates
things from there. If the IF strip is out of alignment, you get a reading error.
Probably worth digging into the service manual on the 3586.
> On Apr 24, 2017, at 6:26 PM, Jerry Hancock <jerry at hanler.com> wrote:
> Orin, Thanks, this goes beyond interesting and I don’t know how you found it. I’ll be staring at this doc for the rest of the week. I have a dozen or so of the Nucleo boards around include the high end F7 types so I’ll see if I can duplicate their code on the System Workbench they reference (and I have installed).
> This afternoon I hooked up the output of my 3586 F0 (with the GPSDO reference) set to 15,000,000.0Mhz and then used my 3336 set to the same (again with the GPSDO) to see if I had any creep on my TDS3054B scope after syncing the two signals. Just setting the 3336 to .001 higher causing the sine waves to go out of sync noticeably in a minute. It’s been running about 2 hours and they still overlap perfectly when set to the same frequency.
> I think we all know what the issue is here in that the 3586 counter is probably adding a count here or there. It’s just curious that it never seems to drop a count. I would have thought I would see +.1 and -.1 with an equal distribution over a reasonable period of time of a few minutes but I don’t; I always see the +.1 or .0, never a 999.9 count (-.01).
> If someone has a 5335 counter in the SF bay area they would like to unload, please send me a note at meters at hanler dot com.
> By the way, your Geller ref is still running perfectly. I’ll have to send it back to you for calibration soon as I think I have had it a year.
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