Delayed vibrato and burble circuit

Claim 2

In combination in an electronic musical instrument: a plurality of selectively actuable control elements for controlling the sounding of musical notes; detector means for detecting a selected condition of said control elements to produce a control signal; means for producing musical tone signals including at least one voltage controlled oscillator; oscillator means for producing electrical signals for modulating said voltage controlled oscillator; a single gate circuit for controlling the application of said modulating electrical signals to said voltage controlled oscillator; and time constant circuit means coupled to said gate circuit and said detector means comprising a first time constant means responsive to said control signal to operate said gate only during an initial time interval to produce a musical effect called burble, a second time constant means responsive to said control signal to operate said gate only after a preselected time interval to produce a musical effect called delayed vibrato, and means for selecting one of said time constant circuits to be operative during any particular time interval.

Claim 3

The combination as claimed in claim 1, wherein said detector means produces said control signal whenever any of said control elements is actuated; said oscillator means is a free running oscillator; and said single gate circuit is coupled between said free running oscillator and said voltage controlled oscillator.

Claim 4

The combination as claimed in claim 2, wherein said single gate circuit comprises a transistor gate connected in shunt between the output of said free running oscillator and a gate bias circuit for biasing said transistor gate in a normally off condition ground; and said time constant circuit means further comprises: a differentiating circuit for producing an output pulse in response to each new control signal; and a differential transistor driving circuit for producing a negative-going signal on a first output lead and a positive-going signal on a second output lead in response to each said output pulse; said first time constant means comprising a bias circuit effective to overcome said gate bias circuit and turn on said transistor gate to shunt said modulating electrical signal to ground, and a first time constant circuit responsive to one of said positive-going and negative-going signals to overcome said first bias circuit and turn off said transistor gate for a short interval to permit said modulating electrical signal to pass; said second time constant circuit means comprising a second time constant circuit responsive to the other of said positive-going and negative-going signals to overcome said second bias circuit and turn on said transistor gate for a short interval to shunt said modulating electrical signal to ground; said selector means comprising a first switching circuit selectively operative to interrupt the output of said first time constant circuit means and a second switching circuit selectively operative to interrupt the output of said second time constant circuit means whereby (1) when said switching circuits are both operated, said transistor gate is off and the musical effect is continuous vibrato; (2) when said switching circuits are both unoperated, the effects of the first and second time constant circuits cancel and the musical effect is no vibrato; (3) when only the first switching circuit is operated, the musical effect is delayed vibrato; and (4) when only the second switching circuit is operated, the musical effect is burble.

Claim 5

The combination as claimed in claim 3, wherein each of said first and second switching circuits comprises a transistor gate coupled between the respective outputs of said first and second time constant means and ground, and a bias circuit including a switch for controlling the operation of said transistor gate.