Controllable reference supply for television tuners

Claim 2

In a television receiver having a voltage controlled tuner, a tuning voltage supply arrangement comprising: a reference voltage supply; a plurality of series connected resistor elements coupled to said reference voltage supply; a first output means coupled to a first junction of said series connected resistor elements for providing a first controllable reference output voltage; a second output means coupled to a second junction of said series connected resistor elements for providing a second controllable reference output voltage different from said first output voltage; a source of automatic fine tuning correction voltage; and means coupling said source of automatic fine tuning voltage to a third junction of said series-connected resistor elements for modifying said first and second output voltages with different voltage contributions from said automatic fine tuning voltage such that said first output means receives a greater automatic fine tuning voltage than said second output means.

Claim 3

The apparatus of claim 1 wherein: said automatic fine tuning voltage is coupled to said series connected resistor elements intermediate said first and second output means.

Claim 4

The apparatus of claim 3 wherein: said first junction is intermediate two of said resistor elements and said second junction is intermediate two others of said resistor elements.

Claim 5

The apparatus of claim 1 wherein: said reference supply has a terminal coupled to ground and provides a reference voltage with respect to ground.

Claim 6

The apparatus of claim 4 wherein: said first output means comprises an amplifier having a relatively high impedance input terminal coupled to said plurality of resistor elements and an output terminal for providing signals at a relatively low impedance.

Claim 7

The apparatus of claim 5 wherein: said second output means comprises an amplifier having a relatively high impedance input teRminal coupled to said plurality of resistor elements and an output terminal for providing signals at a relatively low impedance.

Claim 8

The apparatus of claim 6 wherein said coupling means comprises: an amplifier having an input terminal for receiving automatic fine tuning voltage and an output terminal for providing said tuning voltage at a relatively low impedance; and at least one resistance element coupled between said last-named output terminal and said their junction of said plurality of resistor elements for coupling said automatic fine tuning voltage to said first and second output means.

Claim 9

The apparatus of claim 6 wherein said coupling means comprises: an amplifier having an input terminal for receiving automatic fine tuning voltage and an output terminal for providing said tuning voltage at a relatively low impedance; first and second resistance elements coupled in commmon with said third junction of said plurality of resistor elements; first and second gates each having input terminals for receiving automatic fine tuning voltage from said amplifier, output terminals respectively coupled to said first and second resistance elements and control terminals for receiving signals to control said gates; and means for providing control signals to one of said control terminals in response to a selection of a particular tuning voltage.

Claim 10

The apparatus of claim 7 wherein said plurality of resistor elements are proportioned such that automatic fine tuning voltage provided to said first output means is substantially three times greater than the automatic fine tuning voltage provided to said second output means.

Claim 11

In a television receiver having a voltage controlled tuner, a tuning voltage supply arrangement comprises: a reference voltage supply; first, second, third and fourth resistance elements coupled in series across said reference voltage supply; first output amplifier having an input coupled between said first and second resistance elements and an output terminal for providing a first output voltage; a second output amplifier having an input coupled between said third and fourth resistance elements and an output terminal for providing a second output voltage different than said first output voltage; fifth and sixth resistance elements coupled in common to the junction of said second and third resistance elements; a source of automatic fine tuning voltage; an amplifier having an input for receiving said automatic fine tuning voltage and an output for providing said voltage at a relatively low impedence; first and second gates each having input terminals coupled to said last-named amplifier, output terminals respectively coupled to said fifth and sixth resistance elements and control terminals for receiving signals to control said gates; and means for selectively closing a particular one of said gates to couple automatic fine tuning voltage to said first and second output amplifiers through either said fifth or sixth resistance element.

Claim 12

In a television receiver having a voltage controlled tuner, a tuning voltage supply arrangement comprises: a reference voltage supply; first, second, third and fourth resistance elements coupled in series across said reference voltage supply; first output amplifier having an input coupled between said first and second resistance elements and an output terminal for providing a first output voltage; a second output amplifier having an input coupled between said third and fourth resistance elements and an output terminal for providing a second output voltage different than said first output voltage; fifth and sixth resistance elements coupled in common to the junction of said second and third resistance elements; a source of automatic fine tuning voltage; an amplifier having an input for receiving said automatic fine tuning voltage and an output for providing said voltage at a relatively low impedence; first and second gates each having input terminals coupled to said last-named amplifier, output terminals respectively coupled to said fifth and sixth resistance elements and control terminals for receiving signals to control said gates; and means for selectively closing a particular one of said gates to couple automatic fine tuning voltage to said first and second output amplifiers through either said fifth or sixth resistance element.

Claim 13

The apparatus of claim 10 wherein: said reference supply has a terminal coupled to ground and provides a reference voltage with respect to ground.

Claim 14

The apparatus of claim 11 wherein: the values of said first, second, third and fourth resistance elements are proportioned such that automatic fine tuning voltage provided at the junction of said second and third resistance elements appear at the junction of said first and second resistance elements at a magnitude of substantially three times greater than the magnitude of fine tuning voltage at the junction of said third and fourth resistance elements.