Kabushiki Kaisha Kawai Gakki Seisakusho

Seiji Kameyama

Tatsunori Kondo

Sadaaki Ezawa

Hironori Watanabe

Noriji Sakashita

Hikaru Hashizume

Nobuharu Obayashi

Yutaka Washiyama

Toshio Kugisawa

Kiyomi Takauji

Tohru Aoyama

An electronic musical instrument which is provided with a note frequency data memory for storing note frequency data corresponding to data of key switch depression through a key code register, a note frequency data register for latching and storing the data from the note frequency data memory by a time division pulse from a time division control signal generator, an octave data register for latching and storing octave data from the key code register by the time division pulse from the time division control signal generator, a frequency generator composed of a programmable counter supplied with the output from the note frequency data register to provide a frequency corresponding thereto, a frequency divider array supplied with the frequency and a decoder supplied with the output from the octave data register, the outputs from the respective output ends of the frequency divider array being selected by the output from the decoder in accordance with the octave data, and a musical waveform generator composed of filter circuits corresponding to respective musical instrument sounds and supplied with the output from the frequency generator to provide a musical signal.

Electronic musical instrument

An electronic musical instrument which has a key assignor or assignors of one or more channels for generating and temporarily storing key code corresponding to key depression and release, respectively, a memory for storing waveshape information such as inclination and amplitude variations of a required musical waveshape divided into a plurality of periods so as to read out the waveshape information corresponding to the key code, a plurality of tone source devices, each including waveshape generators of different sound ranges respectively corresponding to keyboard switches in the same channel of each key assignor, the tone source device reading out the waveshape information from the memory on a time divided basis to generate from the waveshape generators waveshapes of different frequencies based on the read out waveshape information, and means for simultaneously actuating the corresponding waveshape generators by the key code from the key assignor and coupler information.

This invention relates to an electronic musical instrument which comprises a waveshape computation cycle, a waveshape transmission cycle and an envelope load output. In the waveshape computation cycle, a musical waveshape is obtained in the form of the accumulation of the products of the nth powers of the fundamental frequency of a cosine wave and coefficients A.sub.n indicating harmonic components of a musical note in certain relationship.

A tone source apparatus for an electronic musical instrument is characterized in that at least one cycle of a musical-tone waveform, which it is desired be produced, is depicted as a sequence of section lines and a series of pulses having regular intervals is varied, by a pulse-density varying circuit, in pulse density in accordance with the degrees of inclination of the respective section lines. The resultant series of pulses having varied pulse density is formed, by a waveform forming circuit, into the desired musical tone waveform. The pulse-density varying circuit comprises a first counter to which is applied as an input, the aforementioned series of pulses having regular intervals. A second counter is connected, in series or in parallel, to the first counter and a decoder is connected to an output terminal of the second counter. A memory circuit is connected to the output terminals of the decoder. The memory circuit comprises a plurality of pulse-density setting portions which set frequency-dividing ratios for the first counter for selecting output pulse-densities. The memory circuit also comprises a plurality of section range setting portions which set frequency-dividing ratios for the second counter for selecting output time intervals of signals obtained at respective output terminals of the decoder.

Tone-source apparatus for electronic musical instrument

A tone source apparatus is provided for an electronic musical instrument. It comprises a memory circuit which has a plurality of addresses and is so arranged that where at least one cycle of a musical tone waveform is divided into p units and a waveform in each section range is represented by a formula containing the abscissa as its variable, a coefficient and a section range quantum number of each formula is memorized in the form of digital signals in the corresponding address. Also included are a clock pulse oscillator, a counter means for counting output clock pulses of the clock pulse oscillator, and a coincidence circuit serving to generate the coincidence signal when the output digital signal of the counter means and a digital signal of the section range quantum number memorized in the memory circuit coincide with one another. A decoder designates the next stage address in order by output signals of the coincidence circuit. A calculation circuit is used for calculating a digital signal from the counter means and a coefficient digital signal from the designated address. A D-A convertor converts the output digital signal of the calculation circuit into a corresponding analog signal. The addresses in the memory circuit have memory portions which memorize as digital signals respective coefficients of n degree multiple term formulae for respective section ranges, and respective section range quantum numbers.

Tone source apparatus for an electronic musical instrument

An apparatus for forming a musical-tone waveform for an electronic musical instrument characterized in that at least one cycle of a musical-tone waveform, which it is desired be produced, is divided in amplitude by dividing lines at equal intervals and sampling points on a time axis are determined from respective crossing points between the waveform and the dividing lines and the distance between the initial and the final sampling points is represented by an appropriate number of pulses so that each sampling point may be represented by a pulse number. There is further provided a memory circuit wherein each sampling point, that is, the pulse number thereof is set up in the form of a digital signal. Additionally, there is a set up in the form of a digital signal a tendency such as increase, decrease or equal at each sampling point with reference to the preceding sampling point. An envelope setting device is used wherein the envelope of a muscial-tone waveform, which it is desired be produced, is subjected to sampling and the analog amount of each sampling point is set up in the form of digital signal. An accumulatively adding device is employed whereby the output digital signal of the envelope setting device is accumulatively added to or subtracted from the output digital signal of the memory circuit. The accumulatively adding device is connected at its output terminal to a D-A converter for converting its output signal into an analog signal.

Musical-tone-waveform forming apparatus for an electronic musical

An electronic musical instrument in which a plurality of order pulse generators and musical-tone waveform forming circuits are connected in order to a tone-source-signal pulse generator. A first pulse-counter circuit and a second pulse-counter circuit are provided in each of the circuits diverging from the output terminal of the tone-source-signal pulse generator to the respective order pulse generators, so that the output signal of the tone-source-signal pulse generator is frequency-divided by the first pulse-counter circuit into 1/x and is then applied as an input signal to the order pulse generator, while the output signal of the tone-source-signal generator is frequency-divided by the second pulse-counter circuit into 1/n and is then applied as a reset pulse to both the first pulse-counter circuit and the order pulse generator. The numbers x and n are integral numbers with the relation 0&lt;x&lt;n. Each musical-tone waveform forming circuit has a sampling number of from 10 to 40.

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Hamamatsu, Japan

Seiji Kameyama