Peak value detector

Claim 1

A circuit for detecting peaks in a time-variant analog signal and converting same to digital form, comprising: a track-hold unit having an input (16) adapted to receive the time-variant signal, a signal storage means (18), a bistable gated switch (14), having a gate terminal, for alternately conducting the time-variant signal to the storage means or isolating the storage means from the time-variant signal, and output terminal (19) continuously connected to the storage means for delivering the stored signal; a comparator for comparing the time-variant signal and stored signal, said comparator having a first input terminal (24) connected to said track-hold unit input terminal (16), a second input terminal (26) connected to said track-hold unit output terminal (19), a first output terminal producing a first logic output signal (Q) when the time-variant signal exceeds the stored signal, and producing at a second output terminal a second logic output signal (Q) when the stored signal equals or exceeds the time-variant signal; circuit means (34a and 34b) responsive to said first logic output signal for applying said first logic signal to the gate terminal of said bistable switch, whereby said switch (14) is in its conducting state only when the time-variant signal exceeds the stored signal; a converter (38) for converting the stored time-variant signal at said track-hold unit output (19) to digital form; said converter having convert-control circuitry (50, 52, 54); an additional circuit means (44 and 48) coupled to said comparator second output terminal for applying said second logic output signal (Q) to said convert control circuitry whereby the converter is put into the convert mode only when the stored signal equals or exceeds the time-variant signal.