[time-nuts] Data collection from 5115A phase noise test set?
John Miles
john at miles.io
Fri Dec 11 20:59:03 EST 2015
> It seems there is no way to estimate frequency from looking at the phase
> data then?
Not to my knowledge. The frequency count chart on the instrument itself is always correct, since it can take the internal baseband offset out of the incoming data. Because TimeLab doesn't have access to that offset, its frequency count chart won't be accurate when acquiring data from the 51xx.
> Does TimeLab have automated collection for the frequency-counter data on
> the control port?
TimeLab doesn't, but I have another collection of quick-and-dirty utilities that includes a way to do it (http://www.ke5fx.com/gpib/readme.htm). The tsccmd.bat file can be run without any arguments to get command help; this option in particular will pull the frequency count entries across as ASCII text:
------------
C:\Program Files (x86)\KE5FX\GPIB>tsccmd 192.168.1.225 "show fcounter"
Using Windows Sockets V2.2 (WinSock 2.0)
Initializing host JMCORE64, address 192.168.1.200
Attempting to connect to server 192.168.1.225:1299 . . .
Connected to server 192.168.1.225:1299
Transmitting "show fcounter" ...
show fcounter
Welcome to the Symmetricom 5125A
=192.168.1.225 > Reference Frequency: 100.0 MHz (auto)
Avg Time (s) Frequency (MHz)
1 9.9999999627589
10 9.99999996274766
100 9.999999962746890
Done, 8 line(s) received
Average rate = 11.0/sec
------------
There's probably a way (wget?) to do something similar in most other OSes -- you basically need to send "show fcounter" to port 1299 with an appropriate timeout interval. Then you can pipe the response to something that parses the text that comes back, if desired.
-- john, KE5FX
Miles Design LLC
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