Electronic musical instrument having a vibrato effecting capability

Claim 1

An electronic musical instrument capable of effecting vibratos with a tone being produced, comprising: a keyboard having a vibrato switch; key detecting means for detecting a key on said keyboard which is pressed down; key constant storing means storing predetermined key constants each being associated with respective one of tones which may be produced by said instrument; address signal generating means for generating an address signal by performing, every predetermined period of time, an arithmetic operation with the key constant associated with the key which is pressed; tone waveform storing means storing amplitudes of a tone waveform each being associated with respective one of a plurality of sampling points, in the form of digital values; digital-to-analog converting means for sequentially converting the digital amplitudes read out of said tone waveform storing means in response to the address signals into an analog tone signal; counting means for counting clock pulses which begin to appear when a power supply of said instrument is turned on; vibrato constant storing means storing vibrato constant each being associated with respective one of the keys on said keyboard; and adding and subtracting means for, when said vibrato switch is pressed, periodically performing addition and subtraction with the key constant and vibrato constant in response to an addition/subtraction switchover signal and an addition/subtraction execution control signal which are constituted by an output of said counting means.