Kabushiki Kaisha Kawai Gakki Seisakusho

Eiji Nagashima

Yoichi Nagashima

Kiyomi Takauji

Tatsunori Kondo

Mineo Kitamura

Tadashi Matsushima

Masafumi Mizoguchi

An electronic musical instrument is provided with a temporal variation circuit of SCF parameters for temporally varying the filter characteristic of a switched capacitor filter circuit, a control circuit for digitally controlling the temporal variation circuit and a touch response circuit for detecting, by scanning, touch response data in performance, whereby temporal variations of a musical waveform signal are digitally controlled.

Electronic musical instrument

An electronic musical instrument which has a keyboard and creates a musical tone by striking keys of the keyboard, is provided with an operation control circuit and an adder both for effecting keyboard switch chattering prevent operation processing and touch response select operation processing, a timing control circuit for controlling the switching between the chattering preventing operation and the touch response detecting operation and the scanning of the keyboard switches to detect their status, a musical tone generator for performing a musical tone generating operation asynchronously with the keyboard switch scanning operation, the keyboard switch chattering preventing operation and the touch response detecting operation, and a transfer circuit for transferring touch response information to the musical tone generator. High-speed touch response detecting operation processing and chattering preventing operation processing which are difficult to execute by a CPU are carried out by the operation control circuit and the adder on a time-shared basis, and data is properly transferred to the musical tone generator which performs the musical signal generating operation asynchronously with the abovesaid operations, thereby implementing low cost touch response processing which is free from hardware limitations on the number of tones to be simultaneously produced and the generator assignment system. Furthermore, data for internal processing is set for two words on a time-shared basis, and touch response data which has such a natural temporal variation curve as is obtainable with a time constant circuit system is directly operated by the operation control circuit and the adder is then rendered to one-word external output data of high precision and resolution, thereby effectively reflecting the tough response data in musical parameters of musical tones to be created.

In an electronic musical instrument which generates a musical waveform by calculating the waveform amplitude value at each sample point through Fourier synthesis, temporal variations of the musical waveform and its timbre variations in accordance with a touch response are controlled with respect to readout addresses for reading out a set of harmonic coefficient data for the Fourier synthesis from a memory having stored therein a plurality of sets of such harmonic coefficient data, thereby changing the component ratio of a harmonic coefficient which will ultimately be used as a Fourier coefficient.

Electronic musical instrument with temporal variation data generating

In an electronic musical instrument which generates a musical waveform by calculating the waveform amplitude value at each sample point through Fourier synthesis, note-range variations of the musical waveform and its timbre variations in accordance with a touch response are controlled with respect to readout addresses for reading out a set of harmonic coefficient data for the Fourier synthesis from a memory having stored therein a plurality of sets of such harmonic coefficient data, thereby changing the component ratio of a harmonic coefficient which will ultimately be used as a Fourier coefficient.

Electronical musical instrument with note frequency data setting circuit

In an electronic musical instrument which generates a musical waveform by calculating the waveform amplitude value at each sample point through Fourier synthesis, there is provided a musical waveform generator for caculating and synthesizing a temporally varying musical waveform at a plurality of sample points, memory circuits for storing two kinds of musical waveforms obtained by the musical waveform generator one after the other and an interpolation circuit for interpolating the two musical waveforms at time intervals shorter than the time intervals used in the musical waveform generator.

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Kami, Japan

Eiji Nagashima