Signal detecting circuit for electronic musical instrument

摘要

A detection circuit for detecting the rise of vibration of a string of a musical instrument such as a guitar capable of producing a trigger signal accurately at each flipping of the string. The circuit comprises a first system in which a signal obtained by full-wave rectifying a picked up signal from a pickup is compared with a predetermined reference level in a first comparator to produce a first signal, a second system in which a signal obtained by half-wave rectifying the picked up signal and integrating it thereafter is compared in a second comparator with a signal obtained by level-shifting the picked up signal by a predetermined level and a second signal is produced by delaying the speed of response of the output of the second comparator, and a flip-flop circuit to which the first and second signals are applied. The flip-flop outputs a signal each time player flips the string, which is used as a trigger signal for an electronic musical instrument driven by the above-said picked up signal.