Constant Fraction Discriminators:

Constant Fraction Discriminators (CFDs) are incorporated into a custom CFD/scaler module which also measures the discriminator firing rates on each channel. The analog bandwidth of this system is >500MHz. The discriminator threshold is programmable by command. This module also has a short adjustable delay element to allow the timing in each channel to be matched at the 1ns level. An analog fanout of the PMT signal is provided from this board to the FADC system.