I have my custom board by using AD9371, and want to measure the noise figure of the receiver.
Can you give some measurement methods to the receiver ?
Thank you !
You can measure the noise figure by either using Y factor or gain method.
Do you mean that I can use the digital value in ADC to estimate the noise figure by Y factor or gain method?
Yes you will have to estimate the NF using the ADC output only.
but I find that the noise floor in ADC output captured by VisualAnalog is higher than the real noise floor, so I can not obtain the real noise floor.
I want to explain why I think the noise floor in ADC output captured by VisualAnalog submerges the real noise floor.
I add the one-stage LNA (Gain: 10dB) in the front end before RF port, Rx, the noise floor in ADC output is around -148dBFS/Hz.
and add two-stage LNA(Gain:25dB) in the front end before RF port, the noise floor in ADC output is still around -148dBFS/Hz. If the noise floor in ADC output captured by VisualAnalog can represent the real system's noise floor, the second result should be greater than -148dBFS/Hz.
This is the reason why I think the noise floor in ADC output captured by VisualAnalog submerges the real noise floor.
Do you mean transceiver noise floor is below -148 dBFS/Hz.?
On my custom board, the noise floor of the ADC output obtained from VisualAnalog is -148dBFS/Hz, No matter how I change external gain !
Can you try feeding a known signal and measuring its power to rule out measurement issue.
Given a single tone, the result is totally correct.
Can you tell me the value of the receiver ( or ADC) noise floor ?
I have measured that noise floor in AD9371 evaluation board is still around -148 dBFS. I don't know whether it is correct.
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