Driver amplifier for an image display device

Claim 2

A video signal processing system comprising: a source of video signals; an image display device for displaying video information in response to video signals applied to an intensity control electrode thereof; a video output driver amplifier with a signal input coupled to said video signal source and a signal output from which amplified video signals are provided to said intensity control electrode of said display device, said amplifier being subject to exhibiting a saturated state in response to large amplitude video signals processed by said amplifier between said signal input and said signal output; and threshold control means coupled to said amplifier and selectively responsive to said video signals processed by said amplifier for reducing the signal gain of said amplifier in response to said large amplitude processed video signals exceeding a threshold level, to preclude said amplifier exhibiting said saturated state.

Claim 3

A video signal processing system comprising: a source of video signals; an image display device for displaying video information in response to video signals applied to an intensity control electrode thereof; a video output driver amplifier with a signal input coupled to said video signal source and a signal output from which amplified video signals are provided to said intensity control electrode of said display device; and threshold control means coupled to said amplifier and selectively responsive to video signals processed by said amplifier for reducing the signal gain of said amplifier in response to large amplitude video signals exceeding a threshold level; wherein a degenerative feedback path is coupled from said amplifier output to said amplifier input; and said threshold control means modifies the impedance of said feedback path for effecting said signal gain reduction.

Claim 4

A video signal processing system comprising: a source of video signals; an image display device for displaying video information in response to video signals applied to an intensity control electrode thereof; a video output driver amplifier with a signal input coupled to said video signal source and a signal output from which amplified video signals are provided to said intensity control electrode of said display device; and threshold control means coupled to said amplifier and selectively responsive to video signals processed by said amplifier for reducing the signal gain of said amplifier in response to large amplitude video signals exceeding a threshold level; wherein a degenerative feedback path is coupled from said amplifier output to said amplifier input; and said threshold control means modifies the impedance of said feedback path for effecting said signal gain reduction.

Claim 5

Apparatus according to claim 2, wherein said feedback path comprises first and second impedance elements; and said threshold means is coupled to said first impedance element for modifying the impedance thereof as presented to said feedback path.

Claim 6

Apparatus according to claim 3, wherein said threshold means comprises switch means responsive to video signals developed at said amplifier output.

Claim 7

Apparatus according to claim 4, wherein said switch means is coupled across said first impedance element.

Claim 8

Apparatus according to claim 5, wherein said switch means comprises semiconductor PN junction means.

Claim 9

Apparatus according to claim 5, wherein said switch means comprises plural series connected semiconductor PN junction means.

Claim 10

Apparatus according to claim 7, wherein a capacitor is coupled from a point between said plural semiconductor PN junction means and a reference potential.

Claim 11

Apparatus according to claim 3, wherein said first and second impedance means respectively comprise first and second resistors; and said first resistor has a larger value than said second resistor and is located nearest to said amplifier output.

Claim 12

A video signal processing system comprising: a source of video signals; an image display device for displaying video information in response to video signals applied to an intensity control electrode thereof; a video output driver amplifier with a signal input coupled to said video signal source and a signal output from which amplified video signals are provided to said intensity control electrode of said display device; and threshold control means coupled to said amplifier and selectively responsive to video signals processed by said amplifier for reducing the signal gain of said amplifier in response to large amplitude video signals exceeding a threshold level; wherein said image display device corresponds to a kinescope with a cathode electrode corresponding to said intensity control electrode; said amplifier comprises a transistor with a first electrode, and second and third electrodes defining a main signal current conduction path of said transistor; video output signals are coupled from said second electrode of said transistor to said cathode electrode; first and second impedance elements comprising a degenerative feedback path for said amplifier are coupled in the order named from said second electrode of said transistor to said third electrode of said transistor; and said threshold control means comprises switch means coupled across said first impedance element and responsive to the magnitude of video output signals developed at said second electrode of said transistor.

Claim 13

A video signal processing system comprising: a source of video signals; an image display device for displaying video information in response to video signals applied to an intensity control electrode thereof; a video output driver amplifier with a signal input coupled to said video signal source and a signal output from which amplified video signals are provided to said intensity control electrode of said display device; and threshold control means coupled to said amplifier and selectively responsive to video signals processed by said amplifier for reducing the signal gain of said amplifier in response to large amplitude video signals exceeding a threshold level; wherein said image display device corresponds to a kinescope with a cathode electrode corresponding to said intensity control electrode; said amplifier comprises a transistor with a first electrode, and second and third electrodes defining a main signal current conduction path of said transistor; video output signals are coupled from said second electrode of said transistor to said cathode electrode; first and second impedance elements comprising a degenerative feedback path for said amplifier are coupled in the order named from said second electrode of said transistor to said third electrode of said transistor; and said threshold control means comprises switch means coupled across said first impedance element and responsive to the magnitude of video output signals developed at said second electrode of said transistor.

Claim 14

Apparatus according to claim 10, wherein said switch means comprises plural semiconductor PN junctions coupled in series across said first impedance element; and a capacitor is coupled from a point between said plural semiconductor PN junctions and a reference potential.

Claim 15

A video signal processing system comprising: a source of video signals; an image display device for displaying video information in response to video signals applied to an intensity control electrode thereof; a video output driver amplifier with a signal input coupled to said video signal source and a signal output from which amplified video signals are provided to said intensity control electrode of said display device; feedback means comprising first and second resistors coupled from said amplifier output to said amplifier input, said feedback means exhibiting an impedance related to the values of said first and second resistors; and threshold conduction means coupled to said first resistor and selectively responsive to video signals processed by said amplifier, for selectively reducing the effective value of said first resistor in response to white going magnitides of said video signals exceeding a threshold level.

Claim 16

A video signal processing system comprising: a source of video signals; an image display device for displaying video information in response to video signals applied to an intensity control electrode thereof; a video output driver amplifier with a signal input coupled to said video signal source and a signal output from which amplified video signals are provided to said intensity control electrode of said display device; feedback means comprising first and second resistors coupled from said amplifier output to said amplifier input, said feedback means exhibiting an impedance related to the values of said first and second resistors; and threshold conduction means coupled to said first resistor and selectively responsive to video signals processed by said amplifier, for selectively reducing the effective value of said first resistor in response to white going magnitides of said video signals exceeding a threshold level.

Claim 17

Apparatus according to claim 12, wherein: said first and second resistors are coupled in the order named from said amplifier output to said amplifier input; and said threshold conduction means is coupled to said amplifier output for responding to the magnitude of output video signals from said amplifier.