Hi, zorro,
Every time at the beginning of the test, out system samples the noise floor for each of the two channels.
And the sampled data was averaged by more than 2000 times. Our noise floor ia about -80dBm at the receiver output.
The noise figure is less than 4dB from the front-end of the LNA to the back-end of ADC, and gain is about 33dB.
The sensitivity is about -113dBm when SNR=3dB.
But when SNR<=15dB, the two channels gain difference deviates the constant more than 0.1dB.
So how to solve this problem?