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AssigneeKabushiki Kaisha Dawai Gakki Seisakusho
InventorsNobuharu Obayashi, Hikaru Hashizume, Noriji Sakashita, Seiji Kameyama, Sadaaki Ezawa, Toshio Kugisawa, Yutaka Washiyama, Tatsunori Kondo, Hironori Watanabe
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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.
A tone source apparatus for an electronic musical instrument, said apparatus comprising a memory circuit which has a plurality of addresses so 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 such formula are memorized as digital signals in a corresponding address, said apparatus further comprising a clock pulse oscillator, a counter means coupled to and counting output clock pulses of the clock pulse oscillator, said counter means producing a digital output signal, a coincidence circuit generating a coincidence signal when the digital output signal of the counter means and a digital signal of the section range quantum number memorized in the memory circuit coincide with one another, decoder means designating the next stage address in order in response to output signal of the coincidence circuit, a calculation circuit for calculating a digital output signal from a digital signal from the counter means and a coefficient digital signal from the designated address, and D-A convertor means for converting the digital output signal of the calculation circuit into a corresponding analog signal.
Dependencies are inferred from the claim text.