Hi Could anyone let me know how to measure relative intensity noise using spectrum analyzer. I got two sets of data and i couldn't relate those two for measuring RIN.
1) I used 2 Ghz photodetector and then i used oscilloscoope to measure ac-component which was 8 mV and dc component was 500 mV. I used spectrum analyzer and the power at that particular frequency id -50dBm.
2)I used 45 Ghz photodetector and then i used oscilloscoope to measure ac-component which was 5 mV and dc component was 10mV. I used spectrum analyzer and the power at that particular frequency id -55dBm.
My question is: while measuring RIN = delta P/ Pavg. Is this delta P is equal to -50 dBm or -55 dB or do i convert ac componet. Also, where does frequency value come from in dB/Hz. Does it depend on photodetector bandwidth or do i take 1Hz bandwidth.
IS Pavg =(Vdc)^2/50 ?
Could anyone please help