Video amplifier for driving a delay line between grounded collector and grounded base

Claim 2

A luminance amplifier for a color television receiver comprising: a. a first transistor, having a base, collector and emitter electrode, said transistor arranged in a common collector configuration, b. a source of composite video signals coupled to said base electrode, c. a second transistor having a base, collector and emitter electrode, said second transistor arranged in a common base configuration, d. a delay line having input and output terminals and a specified characteristic impedance, e. means including a first and a second resistor each of a magnitude substantially equal to said specified characteristic impedance said first resistor coupling said input terminal of said delay line to said emitter electrode of said first transistor and said second resistor coupling said emitter electrode of said second transistor to said output terminal of said delay line to terminate said delay line at said terminals with said specified characteristic impedance for substantially all frequencies within said composite signal, f. a chrominance channel for responding to and processing chrominance components contained in said composite signal, and g. means coupling said emitter electrode of said first transistor to said chrominance channel to apply said composite signal thereto whereby said terminated delay line prevents undesired reflections from interfering with the operation of said chrominance channel.

Claim 3

A video amplifier for use in a color television receiver comprising: a. a source of composite television signals, b. a first transistor arranged in a common collector configuration having an input coupled to said source responsive to said composite television signal, and having a low impedance emitter electrode output circuit, c. a delay line having an input and output terminal and having a given characteristic impedance, d. a second transistor arranged in a common base configuration having a low impedance emitter electrode input circuit and a high impedance collector electrode output circuit, e. a third transistor arranged in a common emitter configuration having an input base electrode circuit coupled to said high impedance collector electrode output circuit of said second transistor, said third transistor having a collector circuit for providing an inverted polarity composite television signal when compared to a signal on said base electrode, f. a fourth transistor in a common collector configuration having a high impedance base electrode circuit coupled to said collector circuit of said third transistor, and having a low impedance emitter output circuit, g. means including a first resistor coupling one terminal of said delay line to said output circuit of said first transistor amplifier and a second resistor coupling said other terminal of said delay line to said input circuit of said second transistor amplifier, said resistors selected of a magnitude substantially equal to said characteristic impedance of said delay line to terminate said delay line for the frequency band of said composite signals, h. a feedback circuit coupled between the input of said second transistor amplifier and said output of said fourth transistor for providing negative feedback to said video amplifier over said frequency band of said composite television signals, for stabilizing said video amplifier operation, i. a chrominance channel for responding to and processing chrominance components contained in said composite signal, and j. means coupling said emitter electrode of said first transistor to said chrominance channel to apply said composite signal thereto whereby said terminated delay line prevents undesired reflections from interfering with the operation of said chrominance channel.

Claim 4

A video amplifier for use in a color television receiver comprising: a. a source of composite television signals, b. a first transistor arranged in a common collector configuration having an input coupled to said source responsive to said composite television signal, and having a low impedance emitter electrode output circuit, c. a delay line having an input and output terminal and having a given characteristic impedance, d. a second transistor arranged in a common base configuration having a low impedance emitter electrode input circuit and a high impedance collector electrode output circuit, e. a third transistor arranged in a common emitter configuration having an input base electrode circuit coupled to said high impedance collector electrode output circuit of said second transistor, said third transistor having a collector circuit for providing an inverted polarity composite television signal when compared to a signal on said base electrode, f. a fourth transistor in a common collector configuration having a high impedance base electrode circuit coupled to said collector circuit of said third transistor, and having a low impedance emitter output circuit, g. means including a first resistor coupling one terminal of said delay line to said output circuit of said first transistor amplifier and a second resistor coupling said other terminal of said delay line to said input circuit of said second transistor amplifier, said resistors selected of a magnitude substantially equal to said characteristic impedance of said delay line to terminate said delay line for the frequency band of said composite signals, h. a feedback circuit coupled between the input of said second transistor amplifier and said output of said fourth transistor for providing negative feedback to said video amplifier over said frequency band of said composite television signals, for stabilizing said video amplifier operation, i. a chrominance channel for responding to and processing chrominance components contained in said composite signal, and j. means coupling said emitter electrode of said first transistor to said chrominance channel to apply said composite signal thereto whereby said terminated delay line prevents undesired reflections from interfering with the operation of said chrominance channel.

Claim 5

The video amplifier according to claim 2 wherein said feedback circuit comprises: a. first and second resistors connected in series between said input of said second transistor and said output of said fourth transistor.

Claim 6

The video amplifier according to claim 3 wherein said feedback circuit further comprises: a. a frequency selective circuit coupled between the junction of said first and second resistors and a point of reference potential for reducing said negative feedback for higher frequency components of said composite signal.

Claim 7

The video amplifier according to claim 2 wherein said feedback circuit comprises: a. a ''''tee'''' network including two series resistors coupled between said input of said second transistor and said output of said fourth transistor, the junction of said resistors coupled to a point of reference potential through a frequency selective feedback network operative to reduce said negative feedback for higher frequency components of said composite signal.

Claim 8

The amplifier according to claim 2 further comprising: a. a variable resistor coupled between said input to said second transistor and a point of reference potential for varying the DC level at said output of said second transistor and therefore the DC level of said composite video signal amplified thereby.

Claim 9

A video amplifier for use in the luminance channel of a color television receiver, comprising: a. first means for providing a composite television signal, b. a first common collector amplifier stage having a low output impedance emitter circuit, and an input coupled to said first means, c. a common base amplifier stage having a low input impedance emitter circuit and an output terminal, d. a delay line having first and second terminals and a given predetermined characteristic impedance, e. first and second resistors, said first resistor being coupled between one terminal of said delay line and said low output impedance emitter circuit of said common collector amplifier, said second resistor being coupled between said other terminal of said delay line and the low input impedance emitter circuit of said common base amplifier, said magnitude of said resistors being substantially equal to said characteristic impedance to terminate said delay line over the range of frequencies contained in said composite television signal, F. a common emitter amplifier stage having an input coupled to said output terminal of said common base amplifier stage, for inverting the polarity of said composite television signal at an output thereof, g. a second common collector amplifier stage having a low output impedance emitter circuit and an input coupled to said output of said common emitter amplifier stage, h. a feedback circuit coupled between the emitter circuits of said common base amplifier and said second common collector amplifier for stabilizing the operating characteristics of said video amplifier over said range of frequencies present in said composite television signals, i. a chrominance channel for responding to and processing chrominance components contained in said composite signal, and j. means coupling said emitter circuit of said common collector amplifier stage to said chrominance channel to apply said composite signal thereto, whereby said terminated delay line prevents undesired reflections from interfering with the operation of said chrominance channel.

Claim 10

A video amplifier for use in the luminance channel of a color television receiver, comprising: a. first means for providing a composite television signal, b. a first common collector amplifier stage having a low output impedance emitter circuit, and an input coupled to said first means, c. a common base amplifier stage having a low input impedance emitter circuit and an output terminal, d. a delay line having first and second terminals and a given predetermined characteristic impedance, e. first and second resistors, said first resistor being coupled between one terminal of said delay line and said low output impedance emitter circuit of said common collector amplifier, said second resistor being coupled between said other terminal of said delay line and the low input impedance emitter circuit of said common base amplifier, said magnitude of said resistors being substantially equal to said characteristic impedance to terminate said delay line over the range of frequencies contained in said composite television signal, F. a common emitter amplifier stage having an input coupled to said output terminal of said common base amplifier stage, for inverting the polarity of said composite television signal at an output thereof, g. a second common collector amplifier stage having a low output impedance emitter circuit and an input coupled to said output of said common emitter amplifier stage, h. a feedback circuit coupled between the emitter circuits of said common base amplifier and said second common collector amplifier for stabilizing the operating characteristics of said video amplifier over said range of frequencies present in said composite television signals, i. a chrominance channel for responding to and processing chrominance components contained in said composite signal, and j. means coupling said emitter circuit of said common collector amplifier stage to said chrominance channel to apply said composite signal thereto, whereby said terminated delay line prevents undesired reflections from interfering with the operation of said chrominance channel.

Claim 11

A video amplifier for use in a color television receiver, comprising: a. a source of composite television signals, b. a delay line having a specified characteristic impedance, and having a first and a second terminal, c. a first transistor arranged in a common collector configuration having an input coupled to said source of composite television signals, and having an emitter electrode output impedance of a magnitude substantially less than said specified characteristic impedance, d. a second transistor arranged in common base configuration and having an emitter electrode input impedance of a magnitude substantially less than said specified characteristic impedance and less than said emitter output impedance of said first transistor, e. a first resistor of a magnitude substantially equal to said characteristic impedance having end terminals, one of said end terminals being coupled to said emitter electrode of said first transistor, and the other of said end terminals being coupled to said first terminal of said delay line, f. a second resistor also of a magnitude substantially equal to said characteristic impedance having end terminals, one of said end terminals being coupled to said emitter electrode of said second transistor and the other of said end terminals being coupled to said second terminal of said delay line whereby said delay line is reliably terminated at both said input and output ends in an impedance substantially matching said characteristic impedance, g. a chrominance channel for responding to and processing chrominance components contained in said composite signal, and h. means coupling said emitter electrode of said first transistor to said chrominance channel to apply said composite signal thereto whereby said terminated delay line prevents undesired reflections from interfering with the operation of said chrominance channel.

Claim 12

A video amplifier for use in a color television receiver, comprising: a. a source of composite television signals, b. a delay line having a specified characteristic impedance, and having a first and a second terminal, c. a first transistor arranged in a common collector configuration having an input coupled to said source of composite television signals, and having an emitter electrode output impedance of a magnitude substantially less than said specified characteristic impedance, d. a second transistor arranged in common base configuration and having an emitter electrode input impedance of a magnitude substantially less than said specified characteristic impedance and less than said emitter output impedance of said first transistor, e. a first resistor of a magnitude substantially equal to said characteristic impedance having end terminals, one of said end terminals being coupled to said emitter electrode of said first transistor, and the other of said end terminals being coupled to said first terminal of said delay line, f. a second resistor also of a magnitude substantially equal to said characteristic impedance having end terminals, one of said end terminals being coupled to said emitter electrode of said second transistor and the other of said end terminals being coupled to said second terminal of said delay line whereby said delay line is reliably terminated at both said input and output ends in an impedance substantially matching said characteristic impedance, g. a chrominance channel for responding to and processing chrominance components contained in said composite signal, and h. means coupling said emitter electrode of said first transistor to said chrominance channel to apply said composite signal thereto whereby said terminated delay line prevents undesired reflections from interfering with the operation of said chrominance channel.

Claim 13

A video amplifier for use in a color television receiver, comprising: a. means for providing a composite television signal, b. a delay line having a specified characteristic impedance, c. a first transistor amplifier arranged in a common collector configuration, having an input coupled to said composite television signal providing means, and having an emitter output circuit of an impedance magnitude significantly less than said specified characteristic impedance, d. a second transistor amplifier arranged in a common base configuration having an emitter input circuit of an impedance magnitude significantly less than said specified characteristic impedance and less than said impedance of said emitter output circuit of said first transistor, and e. means, including a first resistor of a magnitude substantially equal to said specified characteristic impedance coupling said output circuit to one end of said delay line, and a second resistor also of a magnitude substantially equal to said characteristic impedance Coupling the other end of said delay line to said second transistor amplifier input circuit, for providing terminations for said delay line which remain substantially equal to said characteristic impedance over the frequency band of said composite television signals, and which are relatively independent of impedance variations exhibited by the transistors of said amplifiers, f. a chrominance channel for responding to and processing chrominance components contained in said composite signal, g. means coupling said emitter output circuit of said first transistor to said chrominance channel to apply said composite signal thereto whereby said delay line with terminations prevents undesired reflections from interferring with the operation of said chrominance channel.

Claim 14

A video amplifier for use in a color television receiver, comprising: a. means for providing a composite television signal, b. a delay line having a specified characteristic impedance, c. a first transistor amplifier arranged in a common collector configuration, having an input coupled to said composite television signal providing means, and having an emitter output circuit of an impedance magnitude significantly less than said specified characteristic impedance, d. a second transistor amplifier arranged in a common base configuration having an emitter input circuit of an impedance magnitude significantly less than said specified characteristic impedance and less than said impedance of said emitter output circuit of said first transistor, and e. means, including a first resistor of a magnitude substantially equal to said specified characteristic impedance coupling said output circuit to one end of said delay line, and a second resistor also of a magnitude substantially equal to said characteristic impedance Coupling the other end of said delay line to said second transistor amplifier input circuit, for providing terminations for said delay line which remain substantially equal to said characteristic impedance over the frequency band of said composite television signals, and which are relatively independent of impedance variations exhibited by the transistors of said amplifiers, f. a chrominance channel for responding to and processing chrominance components contained in said composite signal, g. means coupling said emitter output circuit of said first transistor to said chrominance channel to apply said composite signal thereto whereby said delay line with terminations prevents undesired reflections from interferring with the operation of said chrominance channel.

Claim 15

In a color television receiver including a color image reproducing device; and an output amplifier stage for driving said reproducing device, said output amplifier stage employing a semiconductor amplifying device exhibiting a relatively low input impedance at an input terminal thereof, and requiring relatively large luminance signal input current variations of a predetermined polarity in order to drive said reproducing device with luminance signals of adequate amplitude and correct polarity; a luminance signal amplifying channel, responsive to the output of said source, for supplying to said input terminal a polarity inverted version of said luminance signals that accords with the input requirements of said output amplifier stage comprising, in combination: a video detector for developing a luminance signal output of a first polarity; a delay line having a predetermined characteristic impedance; an emitter follower amplifier having an input circuit responsive to the luminance signal output of said detector, and having an output circuit, the output impedance of said emitter follower amplifier being appreciably lower than said characteristic impedance of said delay line; means including a first resistor, having a resistance value substantially equal to said characteristic impedance, for coupling said emitter follower output circuit to the input of said delay line; a common base transistor amplifier having an emitter input electrode, and a collector output electrode; means including a second resistor, having a resistance value substantially equal to said characteristic impedance, for coupling the output of said delay line to the emitter electrode of said common base amplifier; a transistor amplifier of common emitter configuration having an input electrode and an output electrode; means for coupling said collector electrode of said common base amplifier to said input electrode to provide at said output electrode amplified luminance signals of said predetermined polarity; a transistor amplifier of common collector configuration having a base input circuit coupled to said output electrode of said common emitter amplifier and an emitter output circuit coupled to said input terminal; means for dynamically reducing the source impedance presented by said channel to said input terminal, said last-named means comprising means for establishing a negative feedback path between said emitter output circuit of said common collector amplifier and said emitter electrode of said common base amplifier; a chrominance channel for responding to and processing chrominance components contained in said composite signal, and means coupling said output circuit of said emitter follower amplifier to said chrominance channel to apply said composite signal thereto, whereby said terminated delay line prevents undesired reflections from interfering with the operation of said chrominance channel.

Claim 16

In a color television receiver including a color image reproducing device; and an output amplifier stage for driving said reproducing device, said output amplifier stage employing a semiconductor amplifying device exhibiting a relatively low input impedance at an input terminal thereof, and requiring relatively large luminance signal input current variations of a predetermined polarity in order to drive said reproducing device with luminance signals of adequate amplitude and correct polarity; a luminance signal amplifying channel, responsive to the output of said source, for supplying to said input terminal a polarity inverted version of said luminance signals that accords with the input requirements of said output amplifier stage comprising, in combination: a video detector for developing a luminance signal output of a first polarity; a delay line having a predetermined characteristic impedance; an emitter follower amplifier having an input circuit responsive to the luminance signal output of said detector, and having an output circuit, the output impedance of said emitter follower amplifier being appreciably lower than said characteristic impedance of said delay line; means including a first resistor, having a resistance value substantially equal to said characteristic impedance, for coupling said emitter follower output circuit to the input of said delay line; a common base transistor amplifier having an emitter input electrode, and a collector output electrode; means including a second resistor, having a resistance value substantially equal to said characteristic impedance, for coupling the output of said delay line to the emitter electrode of said common base amplifier; a transistor amplifier of common emitter configuration having an input electrode and an output electrode; means for coupling said collector electrode of said common base amplifier to said input electrode to provide at said output electrode amplified luminance signals of said predetermined polarity; a transistor amplifier of common collector configuration having a base input circuit coupled to said output electrode of said common emitter amplifier and an emitter output circuit coupled to said input terminal; means for dynamically reducing the source impedance presented by said channel to said input terminal, said last-named means comprising means for establishing a negative feedback path between said emitter output circuit of said common collector amplifier and said emitter electrode of said common base amplifier; a chrominance channel for responding to and processing chrominance components contained in said composite signal, and means coupling said output circuit of said emitter follower amplifier to said chrominance channel to apply said composite signal thereto, whereby said terminated delay line prevents undesired reflections from interfering with the operation of said chrominance channel.

Claim 17

Apparatus in accordance with claim 10 wherein said negative feedback path includes a resistive coupling between said emitter output circuit of said common collector amplifier and said emitter electrode of said common base amplifier.