h4>AbstractAn electronic musical instrument capable of effecting vibratos with any of tones which may be produced by pressing down the keys of a keyboard. A key constant memory stores key constants each being assigned to a different tone, while a vibrato constant memory stores vibrato constants each being assigned to a different tone. The keyboard is provided with an exclusive switch for
effecting vibratos. When this exclusive switch is pressed, a counter which counts clock pulses feeds its output to an adder/subtractor in the form of an addition/subtraction switchover signal and an addition/subtraction execution control signal. In response, the adder/subtractor periodically and alternately performs addition and subtraction with the key constant and vibrato constant associated with a key being pressed down.ClaimsWhat is claimed is:
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.DescriptionBACKGROUND OF THE INVENTION
The present invention relates to an electronic piano or similar electronic musical instrument having a capability of effecting vibratos with a desired tone which is produced by pressing down a key provided on a keyboard.
An electronic musical instrument such as an electronic piano has heretofore been proposed in various forms, as disclosed in Japanese Laid-Open Patent Publication (Kokai) No. 48-34523 by way of example. A prior art instrument of this kind includes a keyboard, a key detector for detecting a key on the keyboard 12 which is pressed down, a key constant memory loaded with key constants each being associated with a different tone which may be produced by pressing a particular key, an address signal generator for
generating an address signal by effecting an arithmetic operation with any of the key constants at a predetermined period, a tone waveform memory storing the amplitudes of a tone waveform associated with various sampling points in the form of digital values, a digital-to-analog (DA) converter for sequentially converting into analog values the digital amplitudes which are associated with the individual sampling
points and read out of the tone waveform memory to thereby produce a tone signal. Various approaches have also been proposed for providing such an instrument with a vibrato effecting capability, as shown and described in Japanese Patent Publication No. 57-22399, for example. Specifically, to effect vibratos with a certain tone, the frequency f of the tone is oscillated up and
