Abstract: A system for converting musical sounds into digital data for use with a electronic synthesizer. An infra red pitch sensor detects pitch of string vibration. Envelope of this signal is filtered and applied to a comparator with floating threshold. Square wave output of comparator is used to reset a continually running counter and latch valid data into a latch. Valid data is used as address for a memory which contains quantized values corresponding to standard musical notes. Transposition of keys may be accomplished in memory lookup table. Amplitude of input signal is detected by A/D converter, and with pitch information from memory lookup table is sent to processor. Processor makes decision when valid data is present, and when present outputs data to synthesizer.

Abstract: An optical pickup system for converting the vibration of the string of a musical instrument into electrical signals, adapted to be used with a pitch calculator system. The pickup is constructed with the plane comprising the optical emitter and detector substantially parallel to the body of the musical instrument. Side walls of the optical pickup prevent the vibration of any string from interfering with the pickup for adjacent strings. The pickup uses a very narrow aperture optical emitter to maximize the signal of the noise ratio of the pickup system. A separate signal from each string is then routed to the pitch calculator circuit.