Power and modulation control system

Claim 3

The system as defined by claim 1 further including a slow start control circuit comprising an RC charging circuit operable at transmitter turnon for providing to said combining circuit a slowly increasing DC signal to a predetermined level.

Claim 4

The system as defined by claim 1 wherein said waveform generator comprises a triangular waveform generator and wherein said control signal applied thereto and generated by said combining circuit means comprises a DC signal.

Claim 5

The system as defined by claim 1 further including circuit means for providing an audio feedback to said comparator thereby controlling distortion in the output signal of said transmitter.

Claim 6

The system as defined by claim 3 wherein said combining circuit means includes: a summing circuit coupled to said first and second circuit means for providing a composite signal therefrom; and an operational amplifier coupled to said summing circuit, being responsive to said composite signal and providing said DC control signal coupled to said waveform generator.

Claim 7

The system as defined by claim 5 wherein said first circuit means comprises: a light emitting semiconductor diode responsive to the output of said transmitter; optical coupler means; and a photosensitive semiconductor signal translation device coupled to said light emitting diode by said optical coupler means and being operative to provide said DC control signal indicative of the power output of said transmitter, said DC control signal being coupled to said summing circuit.

Claim 8

The system as defined by claim 6 wherein said semiconductor signal translating device comprises a transistor having an emitter circuit coupled to said summing circuit.

Claim 9

The system as defined by claim 5 wherein said second circuit means comprises manual power control means providing said desired power output signal.

Claim 10

The system as defined by claim 8 wherein said second circuit means is comprised of: means for selecting a desired power output setting; a digital counter circuit coupled to said power selector means and a pulse source; a digital to analog converter coupled to said counter circuit providing a DC signal indicative of the selected power output, said DC signal being coupled to said summing circuit.

Claim 11

A system as defined by claim 8 wherein said second circuit means additionally includes third circuit means comprising a slow start control circuit coupled to said summing circuit providing still another one of said plurality of control signals.

Claim 12

The system as defined by claim 10 wherein said slow start control circuit comprises an RC charging circuit, operative to generate a third DC signal, coupled to said summing circuit.

Claim 13

A modulator for modulating and controlling the average power output of an RF amplifier comprising in combination: a comparator circuit having first and second inputs respectively coupled to receive a DC biased modulating input signal and a regularly repetitive variable amplitude reference signal and producing a substantially square wave signal consisting of a pulse train in which the width and consequently the duty cycle of the pulses are proportional to the instantaneous amplitude of said DC biased modulating signal relative to the amplitude of the reference signal; input circuit means for providing said modulating input signal including means for providing said DC bias to produce said DC biased modulating input signal, said DC bias establishing a first DC position of said modulating input signal relative to said reference signal and accordingly a gross power output setting of said RF amplifier; a waveform generator, for producing said regularly repetitive variable amplitude reference signal of a predetermined frequency, coupled to said second input of said comparator circuit, said waveform generator being operable in response to an initiating signal of said predetermined frequency and additionally receiving a control input signal for varying the amplitude of said reference signal; control circuit means operable in response to a second power output setting of said RF amplifier, generating said control input signal including circuit means coupling said control input signal to said waveform generator; and filter means coupled to receive said pulse train and produce therefrom a composite signal having an AC and a DC component with the DC component being primarily determined by the average duty cycle of said pulse train and the amplitude of the AC portion being determined by instantaneous duty cycle of said pulse train; and means for coupling said composite signal to said RF amplifier such that the average power of the output signal of said RF amplifier is determined by said DC component and is modulated by said AC component.

Claim 14

A modulator for modulating and controlling the average power output of an RF amplifier comprising in combination: a comparator circuit having first and second inputs respectively coupled to receive a DC biased modulating input signal and a regularly repetitive variable amplitude reference signal and producing a substantially square wave signal consisting of a pulse train in which the width and consequently the duty cycle of the pulses are proportional to the instantaneous amplitude of said DC biased modulating signal relative to the amplitude of the reference signal; input circuit means for providing said modulating input signal including means for providing said DC bias to produce said DC biased modulating input signal, said DC bias establishing a first DC position of said modulating input signal relative to said reference signal and accordingly a gross power output setting of said RF amplifier; a waveform generator, for producing said regularly repetitive variable amplitude reference signal of a predetermined frequency, coupled to said second input of said comparator circuit, said waveform generator being operable in response to an initiating signal of said predetermined frequency and additionally receiving a control input signal for varying the amplitude of said reference signal; control circuit means operable in response to a second power output setting of said RF amplifier, generating said control input signal including circuit means coupling said control input signal to said waveform generator; and filter means coupled to receive said pulse train and produce therefrom a composite signal having an AC and a DC component with the DC component being primarily determined by the average duty cycle of said pulse train and the amplitude of the AC portion being determined by instantaneous duty cycle of said pulse train; and means for coupling said composite signal to said RF amplifier such that the average power of the output signal of said RF amplifier is determined by said DC component and is modulated by said AC component.