A dynamic voicing filter for an electronic organ

Claim 2

A tunable band-pass electronic music voicing system, including a tone signal input terminal, a transistor amplifier having an input control electrode, said transistor amplifier having an output circuit, a first tone filter capacitor connected in series between said signal input terminal and said control electrode, means including a further amplifier connected in cascade with said output circuit, said further amplifier having a grounded resistive output circuit, a second tone filter capacitor connected between a point located between said terminal and said first capacitor and an ungrounded point of said grounded resistive output circuit, said further amplifier being arranged to introduce only a single phase reversal between said terminal and said grounded output circuit, and an output circuit means for said first mentioned transistor amplifier.

Claim 3

The combination according to claim 1, wherein said means including a further amplifier further includes an AC gate connected in series between said output circuit of said transistor and an input circuit of said further amplifier, said AC gate being responsible to a control voltage to vary its impedance.

Claim 4

The combination according to claim 2, wherein said load circuit means includes a further amplifier responsive to signal in said output circuit connected to said first mentioned transistor amplifier, and a loudspeaker driven from said further amplifier.

Claim 5

A tunable tone signal voicing filter having a band-pass characteristic, comprising a first transistor amplifier having a base electrode, a collector electrode and an emitter electrode, a first load resistance connected between said emitter electrode and ground, a signal input terminal, a capacitive tone signal filter connected in series between said signal input terminal and said base electrode, a second feedback transistor amplifier including at least one further transistor having a base electrode, an emitter electrode and a collector electrode, said second transistor amplifier being arranged to introduce only one phase reversal, means driving said second transistor amplifier from said first load resistance, a second load resistance connected between the emitter of said second transistor and ground, a capacitive tone signal filter feedback connection between an ungrounded point of said second load resistance and a point between said signal input terminal and said capacitive tone signal filter, a bias circuit for said first transistor including a resistance connected between said base of said first transistor and ground, and a load device for said first transistor.

Claim 6

A tunable tone signal voicing filter having a band-pass characteristic, comprising a first transistor amplifier having a base electrode, a collector electrode and an emitter electrode, a first load resistance connected between said emitter electrode and ground, a signal input terminal, a capacitive tone signal filter connected in series between said signal input terminal and said base electrode, a second feedback transistor amplifier including at least one further transistor having a base electrode, an emitter electrode and a collector electrode, said second transistor amplifier being arranged to introduce only one phase reversal, means driving said second transistor amplifier from said first load resistance, a second load resistance connected between the emitter of said second transistor and ground, a capacitive tone signal filter feedback connection between an ungrounded point of said second load resistance and a point between said signal input terminal and said capacitive tone signal filter, a bias circuit for said first transistor including a resistance connected between said base of said first transistor and ground, and a load device for said first transistor.

Claim 7

The combination according to claim 4, wherein said means includes a voltage-controlled gate connected between an ungrounded point of said first load resistance and the input circuit of said second transistor amplifier.

Claim 8

The combination according to claim 5, wherein said load device includes another amplifier responsive to tone signal across said first load resistance, and a loudspeaker coupled to be driven by said another amplifier.

Claim 9

The combination according to claim 6, wherein said capacitive tone signal filter and said capacitive tone signal filter feedback connection have substantially equal capacitances.

Claim 10

A tone signal band-pass amplifier having adjustable peaking frequencies comprising a first tone signal amplifier stage having a first series capacitive tone filter in series with an input circuit of said amplifier and having a first output circuit, a negative feedback tone signal amplifier connected in cascade between said output circuit and said input circuit, said negative feedback tone signal amplifier havinG a further output circuit, a second series tone signal capacitor connected from said further output circuit and via said first series capacitive tone filter in driving relation to said first tone signal amplifier, and a variable voltage-responsive impedance connected between said first output circuit and a drive circuit for said negative feedback tone signal amplifier.

Claim 11

A tone signal band-pass amplifier having adjustable peaking frequencies comprising a first tone signal amplifier stage having a first series capacitive tone filter in series with an input circuit of said amplifier and having a first output circuit, a negative feedback tone signal amplifier connected in cascade between said output circuit and said input circuit, said negative feedback tone signal amplifier havinG a further output circuit, a second series tone signal capacitor connected from said further output circuit and via said first series capacitive tone filter in driving relation to said first tone signal amplifier, and a variable voltage-responsive impedance connected between said first output circuit and a drive circuit for said negative feedback tone signal amplifier.

Claim 12

The combination according to claim 8, wherein said variable voltage responsive impedance includes a voltage-responsive AC diode gate having back-to-back diodes, and means for applying control voltage to the junction of said gates.

Claim 13

The combination according to claim 9, wherein said diode gate includes at least one low frequency rolloff capacitor connected in series with said back-to-back diodes.

Claim 14

A dynamic band-pass tone signal filter having constant gain with variable peaking, comprising a first transistor filter stage having a transistor in an emitter follower configuration and having a band-pass filter response, and a feedback loop driven by said transistor, said feedback loop including a controllable diode gate exhibiting voltage-controllable impedance to said tone signal, said feedback loop further including a phase-reversing amplifier providing a low-resistance feedback point coupled to drive said first transistor filter stage.

Claim 15

A dynamic band-pass tone signal filter having constant gain with variable peaking, comprising a first transistor filter stage having a transistor in an emitter follower configuration and having a band-pass filter response, and a feedback loop driven by said transistor, said feedback loop including a controllable diode gate exhibiting voltage-controllable impedance to said tone signal, said feedback loop further including a phase-reversing amplifier providing a low-resistance feedback point coupled to drive said first transistor filter stage.

Claim 16

A variably peaking wideband signal band-pass filter comprising a first transistor amplifier having an input circuit and an output circuit, and a negative feedback path coupling said output circuit to said input circuit, said feedback path including a variable impedance voltage-responsive diode gate capable of transferring said tone signal.

Claim 17

A variably peaking wideband signal band-pass filter comprising a first transistor amplifier having an input circuit and an output circuit, and a negative feedback path coupling said output circuit to said input circuit, said feedback path including a variable impedance voltage-responsive diode gate capable of transferring said tone signal.

Claim 18

The combination according to claim 12, wherein said feedback path further includes a series low frequency rolloff capacitor.

Claim 19

The combination according to claim 13, wherein said input circuit further includes a first series connected tone-signal filter capacitor for said tone signal and wherein said feedback path includes a transistor amplifier connected in cascade with said diode gate and providing a low-impedance coupling resistance, and a further series tone-signal filter capacitor connected between said coupling circuit and via said series-connected tone-signal filter capacitor to complete said feedback path.