Eleonora and Yuhang

Since we have the measurement of qubig PD and NIKHEF PD reported in entry 1728 we could use the measurement result to compute the NIKHEF amplifier gain. The signal transfer is like following:

qubig PD:       PDH signal pk-pk (164mV) = laser power (0.21mW) * photosensitivity (0.27 A/W) * amplifier gain (16e3 V/A) * RF amplification (14dB) * mixer gain * lowpass filter gain

NIKHEF PD:  PDH signal pk-pk (14.8mV) = laser power (1.2mW) * photosensitivity (0.2 A/W) * amplifier gain (we want to know V/A) *  RF amplification (14dB) * mixer gain * lowpass filter gain

Since we are using the same RF amplifier, mixer and lowpass filter, and we know the gain and photo-sensitivity of the quibig PD (16 kV/A) we could calculate the amplifier gain of NIKHEF PD:  ~ 340 V/A(50dB).

We shoud check if this is consistent with the calculation from the electronic schematics. If this is the case we conclude that the Nikhef quadrant has no problem but its gain is too small to be used without amplification.