hi damian,as we know ,if i moudulate the digital signal to the laser and demodulate with a PD,it is a digital communication system.i want to calculate the electrical SNR after receiving from PD.i know there is a device’Electrical Carrier Analyzer (ECAN)’which can calculate the electrical SNR.SO,can it calculate the SNR i want?or is it just calculate the SNR of anolog singal！thank you!