A uhf klystron amplifier having a substantially linear input/output characteristic

Claim 1

A UHF amplifier suitable for amplifying carriers modulated with a plurality of signals comprising a signal path including a directional coupler, a delay circuit having a given delay, an attenuator having as a part thereof a positive, intrinsic, negative diode, and an amplifying Klystron coupled one to another in the order stated; and a control signal developing path comprising a rectifier means coupled to an output from said directional coupler to receive a portion of energy passing through said directional coupler for developing a variable DC control signal proportional to input to said delay circuit from said directional coupler, and means for utilizing said variable DC control signal for controlling attenuation of said attenuator; said given delay of said delay circuit being substantially equal to delay in said control signal developing path extending from said directional coupler to said attenuator; whereby intermodulation products which may be produced by the positive, intrinsic, negative diode and those which may result from inherent nonlinearity of Klystrons are substantially annulled and the amplifying Klystron may be employed efficiently without heavy derating.