Help me with CNR Measurement

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Mansour_M

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Hi Everyone,


I want to measure "CNR" parameter of a receiver. I am using a spectrum analyzer which is not able to measure this parameter so I have to do it manually. However I have no idea how to do it!

Receiver:

Central Frequency: 10 GHz
Modulation: BPSK
symbol Rate: 10 Mbps
 


CNR stands for Carrier-to Noise Ratio. Therefore, adjust your SA to see the modulated spectrum at or around center; then you will see the noise level away from the spectrum. The difference of the spectrum peak and noise floor in dB is the CNR.
Make sure your SA is calibrated during the test.

- - - Updated - - -

In receivers, CNR is defined at input. If you connect the SA after the receiver front end, make sure the signal is not limited. After receiver detector or demodulator (non-linear elements often including a .limiter), the signal-to-noise ratio is different from the input CNR. DEmodulation "gain" is often observed; with BPSK, users rather count transmission errors as BER which is a function of the input CNR.
 

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