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US 4,727,336 AGranted
Wide band low power loss video amplifier
AssigneeZenith Electronics Corporation
InventorWilliam J. Mark
Life of this patent
Estimating the term…
Abstract
Two cascode amplifiers are connected in parallel and include RC bypass circuits across their emitter and collector load resistors. The amplifiers are biased so that positive going transitions of an input video signal drive one amplifier into conduction and negative going excursions drive the other amplifier into conduction. The RC bypass circuits make the amplifier wide band and low power dissipation is obtained because the collector load resistors can be made large.
Claims5
A wide band video amplifier system having an input terminal and an output terminal comprising:
- first and second cascode amplifier means, each coupled between said input terminal and said output terminal and each including load resistor means providing a short time constant for high frequency supply signals;
- means supplying a video signal to said input terminal;
- bias means coupled to said first and to said second cascode amplifier means for enabling alternate conduction of said first and said second cascode amplifier means, to produce output signals, in response to positive going and negative going excursions, respectively, of said video signal;
- and
- said output signals from said first and said second cascode amplifier means being combined at said output terminal.
2 more elements
A wide band, low power loss video amplifier comprising:
- a first cascode amplifier having a first NPN transistor and a second NPN transistor, each having a load resistor, with their collector-emitter circuits connected in series;
- a second cascode amplifier having a first PNP transistor and a second PNP transistor, each having a load resistor, with their collector-emitter circuits connected in series;
- means applying a video signal to both said first NPN transistor and said first PNP transistor;
- first high frequency bypass means comprising individual RC circuits connected in parallel with the load resistor of each of said first transistors;
- second high frequency bypass means comprising a common RC circuit connected in parallel with the load resistor of each of said second transistors;
- and
- bias means for enabling said first cascode amplifier to be driven conductive for positive going excursions of said video signal and said second cascode amplifier to be driven conductive for negative going excursions of said video signal.
4 more elements
Dependencies are inferred from the claim text.