Abstract: A signal generator for a musical instrument includes a voltage-controlled oscillator (VCO) comprising a control voltage input and a VCO output. The control voltage input controls a frequency of the VCO output. A controller is configured to control the voltage-controlled oscillator by inputting a sequence of analog control voltages from a plurality of preloaded control voltage inputs.

Abstract: A voltage controlled filter for an electronic synthesizer incorporates a plurality of individual voltage controlled filter stages connected in cascade with a variable feedback interconnecting the input and output stages. Each of the stages is controlled by application of a series of pulses, with the period between successive pulses determining the cutoff frequency of the filter. Application of pulses to the filter stages at different pulse repetition rates changes the cutoff frequency of the filter and modifies the relative amplitudes of different frequency components of an audio signal to be passed by the filter. The filter is suited for use with high level signals and provides an extremely wide dynamic range through a very high signal-to-noise ratio.

Abstract: An electronic musical instrument incorporates apparatus for producing, on either a triggered or a repetitive basis, a wave form which is employed to produce a variety of musical sounds upon being connected to a loudspeaker. The generator is provided with means for independently modifying the wave shape and frequency of a repetitive signal, each without changing the other.