US 4,198,892 A · Tone generator for electronic musical instrument with digital glissando, portamento and vibrato

Abstract

A tone generator for use with an electronic musical instrument includes a binary counter operated by a binary comparator and a source of clock signals for incrementally advancing or decreasing the state of the counter from a first selected state to a second selected state. The states of the counter control a programmable divider which develops corresponding output tone signals. The counter produces multiple state changes between the selected states so that each individual state change results in a frequency change which is inaudible. The overall effect is to thereby synthesize a tone signal creating the illusion of a continuous pitch change between the pitches corresponding to the selected counter states. The source of clock signals includes a rate multiplier programmed according to the states of the counter to compensate system operation for insuring that similar musical effects defined by corresponding musical intervals are produced in equal time intervals. In a vibrato mode, a second rate multiplier is provided to insure that, for a given frequency output tone signal, different vibrato depths result in vibrato cycles of equal time intervals.

Claims34

Dependent claims

A tone generator for use with a musical instrument comprising:

clock means operable for developing a clock signal;
counting means characterized by a plurality of states, said counting means being enableable for incrementally changing state in response to said clock signal;
means for operating said clock means for developing a clock signal having a repetition rate related to the state characterizing said counting means;
control means operable for selectively enabling said counting means for incrementally changing state;
and
means responsive to said counting means for developing an output tone signal having a frequency corresponding to the state characterizing said counting means.

3 more elements

In an electronic musical instrument having means for selectively developing a digital code representative of a respective musical note, and a vibrato code representative of a vibrato depth about a selected note;

the improvement comprising:
counting means having a clock input and an output;
means for setting the content of said counting means according to a selected one of said digital codes;
means responsive to said selected digital code and to a desired one of said vibrato codes for developing a first deviation code comprising said selected digital code multiplied by said desired vibrato code and a second deviation code comprising said selected digital code divided by said desired vibrato code;
comparison means having a first input for receiving said first and second deviation codes and a second input connected to said counting means output, said comparison means enabling said counting means for counting in a cyclical manner between said first and second deviation codes;
divider means for developing an output tone signal having a frequency corresponding to the content of said counting means.

3 more elements

Dependencies are inferred from the claim text.

Tone generator for electronic musical instrument with digital glissando, portamento and vibrato

Life of this patent

Tone generator for electronic musical instrument with digital glissando, portamento and vibrato

Life of this patent

Abstract

Claims34