Abstract: An electronic musical instrument is provided in which frequency signals are developed by voltage controlled oscillators which are controlled from an analog demultiplexer connected to a scanner of a keyboard and control circuit and in which envelope signals are developed by an envelope synthesizer in synchronized relation to the frequency signals, such frequency and envelope signals being applied to a waveform synthesizer circuit to develop output signals for production of tones. The keyboard and control circuit includes available oscillator and keyboard memories operable from a memory interchange circuit and further includes circuitry for accommodating overload, re-key and an optional portamento operation which is polyphonic in that the frequencies of a plurality of tones can be simultaneously and continuously changed. The circuitry also provides an infinite duration release capability.