Variable phase shift circuit and method

Claim 2

Variable phase shift apparatus comprising: transistor means having base, collector, and emitter electrodes; bias means connected to the electrodes of said transistor means for biasing the electrodes of said transistor means at potentials where said transistor means exhibits a substantial reactive coupling between said base electrode and said collector electrode; means connected to said bias means for varying the potential difference between said base electrode and said collector electrode to vary the reactive coupling therebetween; means connected to said base electrode for providing an input signal thereto; and means connected to said collector electrode for receiving an output signal therefrom, the output signal being a reproduction of the input signal with the phase of the output signal with respect to the input signal being controlled by the magnitude of the potential difference between said base electrode and said collector electrode.

Claim 3

Variable phase shift apparatus as defined in claim 1 wherein said means for varying the potential difference between said base electrode and said collector electrode includes a second transistor means having a control electrode and an output electrode, means connecting said output electrode of said second transistor means to said collector electrode of said first-named transistor means, and means connected to said control electrode of said second transistor means for varying the potential thereof thereby varying the potential of said output electrode of said second transistor means and of said collector electrode of said first-named transistor means.

Claim 4

Variable phase shift apparatus as defined in claim 2 wherein said meaNs connected to said control electrode of said second transistor means includes a nonlinear impedance means connected to said control electrode and means for providing a control voltage connected to said nonlinear impedance means.

Claim 5

Variable phase shift apparatus as defined in claim 2 wherein said bias means connected to said base electrode of said first-named transistor means includes a voltage divider circuit, a first resistance means connected from said voltage divider circuit to said base electrode of said first-named transistor means, and a second resistance means connected from said voltage divider circuit to said control electrode of said second transistor means.

Claim 6

Variable phase shift apparatus as defined in claim 4 wherein said voltage divider circuit includes a first resistor, a diode, and a second resistor connected in series with a potential source, and said first and second resistance means are connected to opposite sides of said diode.

Claim 7

In a color television receiver having a chroma section wherein a chrominance signal is demodulated by synchronous demodulators and in which a reference signal synchronized to a color burst signal is utilized for synchronous demodulation, tint control circuitry for variably shifting the relative phase of the chrominance and reference signals in response to a control voltage comprising: transistor means having base, collector, and emitter electrodes; bias means connected to the electrodes of said transistor means for biasing the electrodes of said transistor means at potentials where said transistor means exhibits a substantial reactive coupling between said base electrode and said collector electrode; means for providing a control voltage connected to said bias means for varying the potential difference between said base electrode and said collector electrode to vary the reactive coupling therebetween in response to a control voltage; and means connected to said base and collector electrodes for coupling one of the chrominance, reference, and color burst signals through the tint control circuitry.

Claim 8

In a color television receiver having a chroma section wherein a chrominance signal is demodulated by synchronous demodulators and in which a reference signal synchronized to a color burst signal is utilized for synchronous demodulation, tint control circuitry for variably shifting the relative phase of the chrominance and reference signals in response to a control voltage comprising: transistor means having base, collector, and emitter electrodes; bias means connected to the electrodes of said transistor means for biasing the electrodes of said transistor means at potentials where said transistor means exhibits a substantial reactive coupling between said base electrode and said collector electrode; means for providing a control voltage connected to said bias means for varying the potential difference between said base electrode and said collector electrode to vary the reactive coupling therebetween in response to a control voltage; and means connected to said base and collector electrodes for coupling one of the chrominance, reference, and color burst signals through the tint control circuitry.

Claim 9

Tint control circuitry as defined in claim 6 wherein said means for providing a control voltage includes a second transistor means having a control electrode and an output electrode, means connecting said output electrode of said second transistor means to said collector electrode of said first-named transistor means, and means connected to said control electrode of said second transistor means for varying the potential thereof.

Claim 10

Tint control circuitry as defined in claim 7 wherein said means connected to said control electrode of said second transistor means includes a nonlinear impedance means connected to said control electrode.

Claim 11

Tint control circuitry as defined in claim 8 wherein said means for coupling one of the chrominance, reference, and color burst signals through the tint control circuitry couples the chrominance signal to said base electrode and receives a phase-shifted chrominance signal at said collector electrode.

Claim 12

Tint control circuitry as defined in claim 7 wherein said means connected to said control electrode of said second transistor means for varying the potential thereof comprises: means responsive to a radiated signal from a remote transmitter for providing a direct voltage of a polarity responsive to said radiated signal; capacitive means connected to said means responsive to a radiated signal for storing a charge responsive to said direct voltage; field effect transistor means having an output electrode and a gate electrode connected to said capacitive means; and means connecting said output electrode of said field effect transistor means to said control electrode of said second transistor means.

Claim 13

Tint control circuitry as defined in claim 10 wherein said means connecting said output electrode of said field effect transistor means to said control electrode of said second transistor means includes a nonlinear impedance means.

Claim 14

Tint control circuitRy as defined in claim 7 wherein said bias means includes a voltage divider circuit, a first resistor connected between said voltage divider circuit and said base electrode of said first-named transistor means, and a second resistor connected between said voltage divider circuit and said control electrode of said second transistor means.

Claim 15

Tint control circuitry as defined in claim 12 wherein said voltage divider circuit includes a third resistor, a diode, and a fourth resistor connected in series with a potential source and said first and second resistors are connected to opposite sides of said diode.

Claim 18

A method of phase shifting an electric signal by a variable amount as defined in claim 14 wherein the electric signal is a chrominance signal in a color television receiver.

Claim 19

A method of phase shifting an electric signal by a variable amount as defined in claim 14 wherein the potential difference between the base and collector is varied by varying the bias potential of the collector.

Claim 20

A method of phase shifting an electric signal by a variable amount as defined in claim 16 wherein the bias potential of the collector is varied nonlinearly with respect to the variation of a control voltage.

Claim 21

A method of phase shifting an electric signal by a variable amount as defined in claim 17 wherein the electric signal is one of the color burst, reference, and chrominance signals in a color television receiver whereby the relative phase of the chrominance and reference signals is varied.