Color television signal demodulation system

Claim 2

A demodulator system including in combination: at least one synchronous demodulator having at least two inputs and at least one output; means coupled with one of the inputs of said demodulator for supplying a modulated carrier signal thereto; means coupled with the other of the inputs of said demodulator for supplying a reference signal thereto at the frequency of said carrier signal; PNP transistor turn-around circuit means coupled with the output of said demodulator; and utilization circuit means coupled with said turn-around circuit means for utilizing the output thereof.

Claim 3

A demodulator system for a color television receiver for composite signals including at least luminance signal components and chrominance subcarrier signal components phase and amplitude modulated with hue and saturation information of a television image, said demodulator system including in combination: at least one demodulator having first and second inputs and at least one output; means coupled to one of the inputs of said demodulator for supplying a modulated subcarrier signal thereto; means coupled to the other input of said demodulator for supplying a reference signal thereto at the frequency of said subcarrier signal and at a predetermined phase relative to the subcarrier signal; PNP transistor turn-around circuit means coupled with the output of said demodulator; emitter-follower circuit means having an input and an output; and means coupling said turn-around circuit means with the input of said emitter-follower circuit means.

Claim 4

A demodulator system for a color television receiver for composite signals including at least luminance signal components and chrominance subcarrier signal components phase and amplitude modulated with hue and saturation information of a television image, said demodulator system including in combination: at least one demodulator having first and second inputs and at least one output; means coupled to one of the inputs of said demodulator for supplying a modulated subcarrier signal thereto; means coupled to the other input of said demodulator for supplying a reference signal thereto at the frequency of said subcarrier signal and at a predetermined phase relative to the subcarrier signal; PNP transistor turn-around circuit means coupled with the output of said demodulator; emitter-follower circuit means having an input and an output; and means coupling said turn-around circuit means with the input of said emitter-follower circuit means.

Claim 5

The combination according to claim 2 further including means coupled with the input of said emitter-follower circuit means for supplying said luminance signal components thereto.

Claim 6

The combination according to claim 2 wherein said demodulator comprises a full wave demodulator including two pairs of switching devices, with the outputs of one paiR of switching devices coupled in common with different ones of the outputs of the other pair of switching devices to form first and second outputs of said demodulator; said means for supplying the modulated subcarrier signal supplies such subcarrier signal at opposite phases to the two pairs of switching devices in said demodulator; said reference signal is supplied to the switching devices of said demodulator, with the common-connected switching devices being alternately rendered conductive at the subcarrier frequency for providing normal and inverted output signals on said first and second outputs; and said turn-around circuit means is coupled with at least one of said first and second outputs of said demodulator.

Claim 7

The combination according to claim 3 including first and second full wave synchronous demodulators each including two pairs of switching devices, with the outputs of one pair of switching devices in each demodulator being coupled in common with different ones of the outputs of the other pair of switching devices to form first and second outputs for each of said demodulators, turn-around circuit means coupled with each of said outputs of said first and second demodulators; wherein said emitter-follower circuit means includes first, second and third emitter-follower circuits each having an input and an output; said means for supplying said luminance signals comprises first, second and third resistor means, each having the same value of resistance, coupled between the inputs of said first, second and third emitter-follower circuits, respectively, and a source of luminance signal components; and said turn-around circuit means comprises first and second turn-around circuits coupled with the first and second outputs, respectively, of each of said demodulators, said first turn-around circuit coupled with the first output of said first demodulator being coupled with the input of said first emitter-follower circuit means, said first turn-around circuit coupled with the first output of said second demodulator being coupled with the input of said second emitter-follower circuit means; and both of the second turn-around circuits coupled with the second outputs of said first and second demodulators being coupled to the input of said third emitter-follower circuit means.

Claim 8

The combination according to claim 5 wherein said third resistor means includes a plurality of sections having at least first and second intermediate taps to which the outputs of said others of said turn around circuit means are connected.

Claim 9

The combination according to claim 4 further including first and second voltage supply terminals and first, second and third current source means; wherein said turn-around circuit means comprises first and second turn-around circuits coupling the first and second outputs, respectively, of said demodulator with said first voltage supply terminal; said first current source means is coupled between said demodulator and said second voltage supply terminal for supplying operating current to said demodulator; and second and third current source means are coupled between said first and second turn-around circuits, respectively, and said second voltage supply terminal.

Claim 10

The combination according to claim 7 wherein said switching devices of said demodulator comprise NPN transistors and said first and second turn-around circuits comprise PNP turn-around circuits.

Claim 11

In a color television receiver for receiving composite signals including at least luminance signal components and chrominance subcarrier signal components phase and amplitude modulated with hue and saturation information of a television image, a demodulator system including in combination: first and second demodulator means each having normal and inverted outputs for deriving from said subcarrier signal components a pair of balanced signals representing two color components of the television image; first, second and third emitter-follower output circuit means; fiRst, second and third resistance means each having the same total value of resistance, said first, second and third resistance means having taps thereon; means for supplying said luminance signal components through said first, second and third resistance means to the inputs of said first, second and third emitter-follower output circuit means, respectively; means coupling one of the outputs of said first demodulator means with the input of said first emitter-follower circuit means at a predetermined tap on said first resistance means; means coupling one of the outputs of said second demodulator means with the input of said second-emitter follower circuit means at a predetermined tap on said second resistance means; and means coupling the other outputs of said first and second demodulator means with the input of said third emitter-follower circuit means at different predetermined taps on said third resistance means.

Claim 12

In a color television receiver for receiving composite signals including at least luminance signal components and chrominance subcarrier signal components phase and amplitude modulated with hue and saturation information of a television image, a demodulator system including in combination: first and second demodulator means each having normal and inverted outputs for deriving from said subcarrier signal components a pair of balanced signals representing two color components of the television image; first, second and third emitter-follower output circuit means; fiRst, second and third resistance means each having the same total value of resistance, said first, second and third resistance means having taps thereon; means for supplying said luminance signal components through said first, second and third resistance means to the inputs of said first, second and third emitter-follower output circuit means, respectively; means coupling one of the outputs of said first demodulator means with the input of said first emitter-follower circuit means at a predetermined tap on said first resistance means; means coupling one of the outputs of said second demodulator means with the input of said second-emitter follower circuit means at a predetermined tap on said second resistance means; and means coupling the other outputs of said first and second demodulator means with the input of said third emitter-follower circuit means at different predetermined taps on said third resistance means.

Claim 13

The combination according to claim 9 wherein said means coupling the outputs of said demodulator means with the inputs of said emitter-follower circuit means comprise first, second, third and fourth PNP transistor turn-around circuits, respectively.

Claim 14

The combination according to claim 10 further including first, second, third, fourth, fifth, and sixth current sources; said first and second current sources coupled between said first and second demodulator means, respectively, and a voltage supply terminal for supplying a predetermined current to each of said first and second demodulator means; and said first, second, third and fourth turn-around circuits coupled through said third, fourth, fifth and sixth current sources, respectively, to said voltage supply terminal; with said first and second current sources supplying the same value of current, and said third, fourth, fifth and sixth current sources supplying the same value of current with a predetermined relationship between said values of current.