Surface Concept Preamplifier-CFD, Manual

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Preamplifier-CFD Manual
3 CFD - Principle of Operation
3.1 CFD - Principle of Operation
The technique of the constant fraction discriminator (CFD) is based on summing the original input signal
to an inverted signal. The original input signal is delayed but of full height, while the inverted signal is
attenuated.
The resulting signal is fed into a zero-crossing comparator. This allows obtaining precise timing
information that eliminates any walk error, which is induced by constant rise time and varying signal
amplitudes.