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NF data stream / Receiving wrong data?


Michal92
(@michal92)
Active Member
Joined: 8 years ago
Posts: 6
Topic starter  

Hi,

I have a problem with Spectran NF-5035 X. I set start freq, stop freq, resbandw, vidbandw and sweeptime for required values - this works (verified by getting this values from device).
Afterwards I set USBMEAS to 1, recieve some bytes and set USBMEAS back to 0.
In Spectran API Documentation are incoming data described like "0x22 time time time time freq freq freq freq min min min min max max max max". I'm getting these lines (in decimal format):

35 76 91 72 47 7 -128 -110 4 0 0 7 34 -87 54 7 34 -87 54
35 114 -127 89 47 7 0 -80 4 0 0 -85 48 111 54 -85 48 111 54
35 31 38 104 47 7 0 -50 4 0 0 -12 75 67 54 -12 75 67 54
35 -13 -33 118 47 7 0 -20 4 0 0 -12 75 67 54 -12 75 67 54
35 -4 -125 -123 47 7 0 5 0 0 -78 24 -118 54 -78 24 -118 54
35 -111 62 -108 47 7 0 40 5 0 0 -78 24 54 -78 24 54
35 -100 -30 -94 47 7 0 70 5 0 0 -12 75 67 54 -12 75 67 54
35 118 -100 -79 47 7 0 100 5 0 0 -78 24 54 -78 24 54
35 -87 64 -64 47 7 0 -126 5 0 0 0 0 0 0 0 0 0 0
35 -82 -14 -50 47 7 0 -96 5 0 0 -85 48 111 54 -85 48 111 54

But 35 DEC = 23 HEX, so I don't now whats wrong. Also total number of bytes in one "sentence" is 19, not 17.. :(

Do you have any ideas, what's wrong?
I'm not using usbconnector.cpp etc., because I'm writing my program in Java.

Thanks for advices..


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Michal92
(@michal92)
Active Member
Joined: 8 years ago
Posts: 6
Topic starter  

Problem (almost) solved. In Spectran API Documentation is AMPFREQDAT described for HF and it works. But I don't know, what bytes are in data sentence recieved from NF Spectran..


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mm_dev
(@mm_dev)
Member Admin
Joined: 11 years ago
Posts: 321
 

Yes, NF data is slightly different and has 2 more bytes per package to specify the used sensor, between timestamp and frequency. Also the frequency value is "Hz * 10" instead of "Hz / 10" for NF values, and obviously the actual measurement values are using different units than dBm: Magnetic sensors are in Tesla, Electric sensor in Volt/Meter and Analog input in Volt.


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Michal92
(@michal92)
Active Member
Joined: 8 years ago
Posts: 6
Topic starter  

mm_dev: Thanks a lot! ;)


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Michal92
(@michal92)
Active Member
Joined: 8 years ago
Posts: 6
Topic starter  

Sorry that I am opening this topic again, but I have a problem which I still didn't solve.
I set this values:

- RBW: 300 Hz
- Attenuation factor: 0 (off)
- Sweeptime: 2000ms
- Sensor mode: 7
- Samp proc: Min/Max (Peak works almost the same)
- Span freq: 0
- Center freq: 0.010 (10 kHz)

I start USB measuring, download data etc. But I'm getting wrong values, for 10kHZ:
freq 0.01, V:3.5810997E-5 = uV:35.810997009277344 => dBuV: 31.08

I'm getting almost same values for range from 10 to 150kHz. I tried to connect instrument for EMC, but I still had straight line without peaks. MCS Spectrum Analyzer works ok with same settings, there are peaks etc.

Is there any variable or something what I forgot to set up?
Thank you for your help! ;)


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Moderator
(@moderator)
Member Admin
Joined: 12 years ago
Posts: 1048
 

In Zero Span Mode you get no spectrum...

Snip


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