A CIRCUIT FOR CONVERTING A VARIABLE FREQUENCY PULSE TRAIN INTO A RELATED ELECTRIC VOLTAGE

摘要

A frequency-to-DC converter circuit for producing an output voltage related to the frequency of a train of input pulses. The circuit includes an improved "diode pump" circuit in which the input capacitor discharges through a diode only to a given reference voltage different from ground potential during the period between successive input pulses. The reference voltage approximates the instantaneous voltage across the circuit storage capacitor. The output voltage is preferably taken from the junction of an RC time constant circuit. The converter is especially adapted to provide a speed signal in an anti-lock brake system.