US 4,120,226 AGranted

Circuit for reiterating percussive sounds in electronic musical instrument

AssigneeCBS Inc.

InventorRobert A. Finch

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Abstract

For reiteration of percussive sounds in an electronic organ there is provided a circuit for generating pulse signals for reiteration control which are "on" for much longer periods than they are "off", thereby substantially reducing the chance of an organ key being actuated when the control signal is in its "off" condition. The circuit is so arranged that playing of an additional key at a time when one or more other keys are being held has no effect on the reiteration of the sound produced by the held keys. The circuit generates four control signals which are connected such that each controls three notes in a given octave on the keyboard, a different three in successive octaves, such that when normal intervals (e.g., thirds, fourths and fifths) are played, the effect of random reiteration control is produced.

Claims7

Dependent claims

In an electronic organ having a plurality of keyswitches wherein actuation of each keyswitch acts to apply as one of two inputs to a respective one of a like plurality of logic gates a DC potential of predetermined amplitude, and wherein conduction of a logic gate acts to cause an associated one of a like plurality of audio gate circuits to couple from a tone generator to output utilization means a single note of a musical scale corresponding to the actuated keyswitch, a reiteration circuit for automatically reiterating a sound corresponding to a note for so long as the keyswitch for that note is depressed to produce percussion effects, said system comprising:

pulse generating means for producing a repetitive substantially rectangular waveform pulse signal having a first voltage level during a substantially greater portion of each cycle than it has a second voltage level, which first level being sufficient when applied as a second input to a logic gate simultaneously with application of said DC potential as a first input to render said logic gate conducting and said second level being incapable of rendering a logic gate conducting when applied thereto simultaneously with the application of said DC potential, whereby to minimize the chance of a keyswitch being actuated when said repetitive pulse signal is at said second level;
and
means connecting said pulse generating means to said logic gates for coupling said repetitive pulse signal as a second input to selected ones of said logic gates.

In an electronic organ having a plurality of keyswitches wherein actuation of each keyswitch acts to apply a DC potential of predetermined amplitude as one of two inputs to a respective one of a like plurality of logic gates, and wherein conduction of a logic gate acts to cause an associated one of a like plurality of audio gates to couple from a tone generator to output utilization means a single note of a musical scale corresponding to the actuated keyswitch, a reiteration circuit for automatically reiterating a sound corresponding to a note for so long as the keyswitch for that note is depressed to produce percussion effects, said system comprising:

pulse generating means for producing first, second, third and fourth repetitive substantially rectangular waveform pulse signals each of which has a first voltage level during a substantially greater portion of each cycle than it has a second voltage level, which first voltage level being sufficient when applied as a second input to a logic gate simultaneously with application of said DC potential as a first input to render said logic gate conducting and said second level being incapable of rendering a logic gate conducting when applied thereto simultaneously with appliction of said DC potential, said first and second repetitive signals being out of phase relative to each other and said third and fourth repetitive signals having substantially the same frequency as said first and second repetitive signals and not locked in phase therewith, said third and fourth repetitive signals being out of phase relative to each other;
and
connecting means for coupling said first, second, third and fourth repetitive pulse signals to first, second, third and fourth groups, respectively, of logic gates whose associated audio gates respectively control first, second, third and fourth preselected sets of notes in a given octave.

Dependencies are inferred from the claim text.