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TRF371109: TRF371109 Gain Measurement using RF Power Method

Part Number: TRF371109

Hello:

I have measured the I/Q demodulator gain using the voltage method, i.e. 20*log( vrms of BB I/vrms of mixer input) at 926MHz and got close to the datasheet typical gain of 41dB.

Now, I am measuring the same I/Q demodulator gain, using RF power method. I would like to make sure the method I am using below is correct. 

I inject a -40dBm into the I/Q demodulator mixer input (I took into account the balun/TL loss) so at the J6 on the EVM board, the RF power level is -39dBm.

The RF freq is 926MHz, the LO freq is at 925MHz at about 0dBm at J7 on the EVM board.

I measured the BB I output at the SMA connector J3 using a 50 Ohm input impedance spectrum analyzer set to 1MHz center frequency. I measured -10dBm at 1MHz. The TRF371109 EVM says the balun loss is about 12dB, so adding that to -10dBm gives me +2dBm. So gain = 2dBm - (-40dBm) = 42dB. So I am arriving at the same gain as before when measured using the voltage method. 

I just want to double check that this is all correct. Please confirm or correct if I am making mistake.

Thanks.