constant fraction discriminator

When measuring the arrival time of pulses with a fixed threshold the time measured exhibits a measurement error that is a function of the pulse amplitude. For setups where pulses have varying amplitudes but a constant rise time, a constant fraction discriminator (CFD) can reduce this error. Measuring a signal at two or three fixed thresholds with a high-resolution TDC can achieve the same quality of time walk correction as a CFD.

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