Takeji Kimura

Integrated circuit for an electronic musical instrument

The present invention is an integrated circuit for an electronic musical instrument comprising: a plurality of frequency divider chains receiving a plurality of input signals for dividing the frequencies of the input signals one after another and corresponding to a plurality of series of adjacent notes which are chromatically arranged in turn in a twelve-tone of a musical scale, respectively; keyer-gates for switching on and off the input signals and output signals of the frequency dividers of the frequency divider chains respectively; and adding means for adding at least two output signals of the keyer-gates which correspond to the adjacent notes chromatically arranged to each other, so as to produce output tone signals therefrom, respectively.

Tone generator system for an electronic organ

A tone generator system for an electronic organ which is capable of being fabricated into an LSI structure and receives a saw-tooth wave or staircase wave as an input thereto comprises a frequency divider for the saw-tooth wave or staircase wave including a ladder resistor network and a complementary MOS FET devices, an analog switch having a wide dynamic range and a high linearity in input-output transfer characteristic constructed by MOS FET devices to serve as an indirect keying means, a sustain means including a novel structure of a variable impedance element which is constructed to control a channel current in a MOS FET device by varying a potential distribution in a source region, and an impedance converter constructed by complementary MOS FET devices and free from a D.C. level shift. With the above arrangement a tone generator system of high quality for an electronic organ is provided.

An MOS analog LSI for electronic organ systems

This paper will describe an MOS analog LSI for electronic organs which generates a natural tone decay envelope by a resistive-source MOS device, and also preferable tone spectrum by a sawtooth wave divider using a modified R-2R network.