Sheila, Haocun
We are trying to compare the amplitudes of 90MHz and 36MHz modulations at the AS port.
1. Using gpib connected to Agilent 4395A to measure the spectra of photo-current signals. The measurements are 1E-7 V/rtHz for 36MHz, 6E-8 V/rtHz for 45MHz, and 7E-8 V/rtHz for 90MHz.
All three signals are at the similar level.
2. Using RF detectors to check the input signal of demodulator, which are -18dBm for 36MHz, -12dBm for 45MHz, and -28dBm for 90MHz.
The 90MHz is lower, about 1/4 of 36MHz.
3. From measurements coming out from the demodulator are: 2943 counts for 36MHz, 2557cnts for 45MHz, and 17cnts for 90MHz (after being divided by gains).
The factor drops to < 1/100.
These results are not consistent with each other, and we will check by changing the whitening gains and the demodulator.