Fretboard to synthesizer interface apparatus

DETAILED DESCRIPTION According to the invention, a small current is caused to flow through one guitar string at a time.
As current is flowing through a particular string, a voltage detection means is placed across fret pairs in succession, starting preferably with the highest two frets and progressing towards the open note end.
Upon finding a voltage greater than some predetermined value at the output of the voltage detection means, scanning is halted and the fret number and string number is stored prior to going to the next string and its scan.
This procedure continues cyclically with updating occurring every few milliseconds.
Specific inventive features include the use of differential amplifier means as a voltage detector means and the use of a "shorting string" to insure reliable operation of the circuitry as described in more detail below.