Compensated television matrix amplifiers

Claim 2

An amplifier for matrixing a luminance signal with a color difference signal of the type employing a first transistor of a specified conductivity having an emitter electrode coupled to an emitter electrode of a second transistor of an opposite conductivity, said first transistor having said color difference signal applied to the base electrode thereof, and said second transistor having said luminance signal applied to said base electrode thereof, said first transistor operating in a common emitter mode for said color difference signals and in a common base mode for said luminance signals, said gain in said common base mode being a function of the magnitude of the impedance at the base electrode of said first transistor, the improvement therewith comprising, a. a circuit having a predetermined frequency response coupled to the base electrode of said first transistor, said circuit undesirably increasing in impedance for higher frequency luminance signals, which impedance increase undesirably reduces said common base gain to thereby adversely affect matrixing, and b. a frequency selective network coupling the emitter electrode of said first transistor to the emitter electrode of said second transistor, and selected to provide an increasing signal to said first transistor''s emitter for those higher frequency luminance signals at which said magnitude of said circuit coupled to said base of said first transistor increases.

Claim 3

The amplifier according to claim 1 wherein, said frequency selective network comprises a resistor connected in parallel with a capacitor.

Claim 4

An electrical circuit for matrixing a color difference signal occupying a first band of frequencies with a luminance signal occupying a second wider band of frequencies for providing a color signal comprising: a. first and second transistors of opposite conductivity types, each having a base, collector and emitter electrode, b. means including a frequency selective network for coupling the emitter electrode of said first transistor to the emitter electrode of said second transistor, c. input circuit means for said color difference signal coupled between the base electrode of said first transistor and a point of reference potential, said input circuit means providing at the base electrode of said first transistor a low impedance termination for said luminance signals, d. input circuit means for said luminance signal coupled between the base electrode of said second transistor and said point of reference potential to operate said first transistor in a common base mode for said luminance signals, said frequency selective means serving to compensate for any changes in common base gain due to a variation in said magnitude of said low impedance termination for said luminance signals at the base electrode of said second transistor, e. output utilization means coupled to said collector electrode of said first transistor.

Claim 5

An electrical circuit for matrixing a color difference signal occupying a first band of frequencies with a luminance signal occupying a second wider band of frequencies for providing a color signal comprising: a. first and second transistors of opposite conductivity types, each having a base, collector and emitter electrode, b. means including a frequency selective network for coupling the emitter electrode of said first transistor to the emitter electrode of said second transistor, c. input circuit means for said color difference signal coupled between the base electrode of said first transistor and a point of reference potential, said input circuit means providing at the base electrode of said first transistor a low impedance termination for said luminance signals, d. input circuit means for said luminance signal coupled between the base electrode of said second transistor and said point of reference potential to operate said first transistor in a common base mode for said luminance signals, said frequency selective means serving to compensate for any changes in common base gain due to a variation in said magnitude of said low impedance termination for said luminance signals at the base electrode of said second transistor, e. output utilization means coupled to said collector electrode of said first transistor.

Claim 6

An amplifier for matrixing signals in a first band of frequencies with signals in a second band of frequencies having a bandwidth substantially greater than said first band, comprising, a. a first transistor of a specified conductivity having a base, collector and emitter electrode, b. a second transistor of opposite conductivity having a base, collector and emitter electrode, c. means for applying operating potential between said first and second transistor''s collector electrodes, d. first signal input circuit means for signals in said first band of frequencies, coupled to the base electrode of said first transistor, said input circuit means having a bandwidth capable of passing said first band of frequencies and an impedance for providing a signal bypass for frequencies above said first band of frequencies and within said second band of frequencies, e. second signal input circuit means for signals in said second band of frequencies, coupled to the base electrode of said second transistor, f. means coupling the emItter electrode of said first transistor to the emitter electrode of said second transistor, said means including means for compensating for any change in impedance of said first signal input means at frequencies within said second band of frequencies, g. means coupled to said collector electrode of said first transistor for utilizing the matrixed output of said first and second band of frequencies produced thereby.

Claim 7

An amplifier for matrixing signals in a first band of frequencies with signals in a second band of frequencies having a bandwidth substantially greater than said first band, comprising, a. a first transistor of a specified conductivity having a base, collector and emitter electrode, b. a second transistor of opposite conductivity having a base, collector and emitter electrode, c. means for applying operating potential between said first and second transistor''s collector electrodes, d. first signal input circuit means for signals in said first band of frequencies, coupled to the base electrode of said first transistor, said input circuit means having a bandwidth capable of passing said first band of frequencies and an impedance for providing a signal bypass for frequencies above said first band of frequencies and within said second band of frequencies, e. second signal input circuit means for signals in said second band of frequencies, coupled to the base electrode of said second transistor, f. means coupling the emItter electrode of said first transistor to the emitter electrode of said second transistor, said means including means for compensating for any change in impedance of said first signal input means at frequencies within said second band of frequencies, g. means coupled to said collector electrode of said first transistor for utilizing the matrixed output of said first and second band of frequencies produced thereby.

Claim 8

The amplifier according to claim 4 wherein said means coupling the emitter electrode of said first transistor to the emitter electrode of said second transistor include a resistor in parallel with a capacitor.

Claim 9

In a color television receiver having a color television signal processing path including at least a color demodulator operative to produce a separate color difference signal for each primary color, said processing path including a luminance channel for amplifying a monochrome component contained within said color television signal, in combination therewith, apparatus for matrixing said color difference signals with said monochrome component, comprising, a. first, second and third transistors of specified conductivity, each having a base, emitter and collector electrode, b. a fourth transistor of opposite conductivity having a base, emitter and collector electrode, c. means coupling said collector electrode of said fourth transistor to a point of reference potential, d. first, second and third low pass filters having a low output impedance at said luminance channel frequencies within said color difference frequency band, e. means for coupling said first low pass filter between said first transistor''s base and an output of said color demodulator for providing one separate color difference signal to said first transistor, means for coupling said second low pass filter between said second transistor''s base and a second output of said color demodulator for providing another color difference signal to said second transistor and means for coupling said third low pass filter between said third transistor''s base and still another output of said color demodulator for providing still another color difference signal for said third transistor, f. first, second and third frequency selective networks each separate one coupled between the emitter electrode of one of said first, second and third transistors and the emitter electrode of said fourth transistor, to compensate said first, second and third transistors for any variation of said low output impedance at said base electrodes due to frequencies of said luminance signals not within said color difference frequency band, g. means coupled to the base of said fourth transistor for driving said first, second and third transistors with said monochrome component in a common base mode, h. means coupled to said first, second and third transistors'' collector electrodes for utilizing a signal produced at said electrodes, said signal at said collector electrodes varying in accordance with said corresponding transistor base-associated color difference signal and said luminance signal.

Claim 10

In a color television receiver having a color television signal processing path including at least a color demodulator operative to produce a separate color difference signal for each primary color, said processing path including a luminance channel for amplifying a monochrome component contained within said color television signal, in combination therewith, apparatus for matrixing said color difference signals with said monochrome component, comprising, a. first, second and third transistors of specified conductivity, each having a base, emitter and collector electrode, b. a fourth transistor of opposite conductivity having a base, emitter and collector electrode, c. means coupling said collector electrode of said fourth transistor to a point of reference potential, d. first, second and third low pass filters having a low output impedance at said luminance channel frequencies within said color difference frequency band, e. means for coupling said first low pass filter between said first transistor''s base and an output of said color demodulator for providing one separate color difference signal to said first transistor, means for coupling said second low pass filter between said second transistor''s base and a second output of said color demodulator for providing another color difference signal to said second transistor and means for coupling said third low pass filter between said third transistor''s base and still another output of said color demodulator for providing still another color difference signal for said third transistor, f. first, second and third frequency selective networks each separate one coupled between the emitter electrode of one of said first, second and third transistors and the emitter electrode of said fourth transistor, to compensate said first, second and third transistors for any variation of said low output impedance at said base electrodes due to frequencies of said luminance signals not within said color difference frequency band, g. means coupled to the base of said fourth transistor for driving said first, second and third transistors with said monochrome component in a common base mode, h. means coupled to said first, second and third transistors'' collector electrodes for utilizing a signal produced at said electrodes, said signal at said collector electrodes varying in accordance with said corresponding transistor base-associated color difference signal and said luminance signal.