Gain monitoring of distortion cancellation amplifiers in a feedforward linear amplifier

Claim 2

A monitor signal injection system for monitoring defects in circuit in a feedforward cancellation amplifier, comprising: an input sampling coupler; a monitor signal generator for generating monitor signals; a monitor signal coupler, connected to said monitor signal generator and said input sampling coupler, for injecting monitor signals for monitoring circuits in the feedforward cancellation amplifier; a main amplifier connected to said monitor signal coupler; an output sampling coupler connected to said main amplifier; an attenuator connected to said output sampling coupler; a matching circuit connected to said input sampling coupler; a first delay line connected to said matching circuit; a fundamental cancelling coupler connected to said attenuator and said first delay line; a distortion amplifier connected to said fundamental cancelling coupler; a second delay line connected to said output sampling coupler; and a distortion cancelling coupler, connected to said second delay line and said distortion amplifier, for cancelling the monitor signals along with distortion and noise.

Claim 3

A monitor signal injection system according to claim 1, wherein the level of monitoring signals for monitoring is greater than -20 dBm, and wherein the level of monitor signals output is approximately -10 dBm.

Claim 4

A monitor signal injection system for monitoring defects in various circuits, comprising: an input sampling coupler for receiving input signals; a first feedforward cancellation amplifier including: a main amplifier coupled to said input sampling coupler; a first output sampling coupler coupled to said main amplifier; a first attenuator coupled to said first output sampling coupler; a first matching circuit coupled to said first input sampling coupler; first delay means, coupled to said first matching circuit, for receiving and delaying the input signals; a first fundamental cancelling coupler coupled between said first delay means and said first attenuator; second delay means coupled to said first output sampling coupler; a first distortion amplifier coupled to said first fundamental cancelling coupler; and a first distortion cancelling coupler coupled between said first distortion amplifier and said second delay means, for outputting a power; a monitor signal generator for generating monitor signals; a monitor signal coupler, connected to said input sampling coupler and said monitor signal generator, for injecting constant amplitude monitor signals into said main amplifier; a second feedforward cancellation amplifier coupled to said first feedforward cancellation amplifier including: a second matching circuit coupled to said input sampling coupler; third delay means, coupled to said second matching coupler, for providing delay signals; a second output sampling coupler coupled to said first distortion cancelling coupler; a second attenuator coupled to said second output sampling coupler; a second fundamental cancelling coupler coupled to said second attenuator and said third delay means; a second distortion amplifier coupled to said second fundamental cancelling coupler; fourth delay means, coupled to said second output sampling coupler; and a second distortion cancelling coupler, coupled to said fourth delay means and said second distortion amplifier, for outputting a fundamental output power.

Claim 5

A monitor signal injection system for monitoring defects in various circuits, comprising: an input sampling coupler for receiving input signals; a first feedforward cancellation amplifier including: a main amplifier coupled to said input sampling coupler; a first output sampling coupler coupled to said main amplifier; a first attenuator coupled to said first output sampling coupler; a first matching circuit coupled to said first input sampling coupler; first delay means, coupled to said first matching circuit, for receiving and delaying the input signals; a first fundamental cancelling coupler coupled between said first delay means and said first attenuator; second delay means coupled to said first output sampling coupler; a first distortion amplifier coupled to said first fundamental cancelling coupler; and a first distortion cancelling coupler coupled between said first distortion amplifier and said second delay means, for outputting a power; a monitor signal generator for generating monitor signals; a monitor signal coupler, connected to said input sampling coupler and said monitor signal generator, for injecting constant amplitude monitor signals into said main amplifier; a second feedforward cancellation amplifier coupled to said first feedforward cancellation amplifier including: a second matching circuit coupled to said input sampling coupler; third delay means, coupled to said second matching coupler, for providing delay signals; a second output sampling coupler coupled to said first distortion cancelling coupler; a second attenuator coupled to said second output sampling coupler; a second fundamental cancelling coupler coupled to said second attenuator and said third delay means; a second distortion amplifier coupled to said second fundamental cancelling coupler; fourth delay means, coupled to said second output sampling coupler; and a second distortion cancelling coupler, coupled to said fourth delay means and said second distortion amplifier, for outputting a fundamental output power.

Claim 6

A monitor signal injection system according to claim 3, wherein levels of monitor signals from said monitor signal generator are always greater than -20 dBm, and the level of monitor signals output is approximately -10 dBm.

Claim 7

A monitor signal injection system according to claim 4, wherein said first and second distortion cancelling couplers cancel the monitor signals along with distortion and noise.