Automatic control system for reducing distortion produced by electrical circuits
AssigneeLucent Technologies Inc.
InventorRobert Evan Myer
Life of this patent
Estimating the term…
Abstract
An automatic control system for reducing distortion produced by electrical circuit where a pilot signal pulse is applied to the electrical circuit for a period of time during which the system determines the adjustments to be made to its circuitry to reduce the distortion.
Claims17
An automatic control system for reducing distortion comprising an electrical circuit that produces distortion, said automatic control system comprising:
- a cancellation circuit coupled to the electrical circuit, the cancellation circuit is configured to isolate the distortion produced by the electrical circuit;
- and
- switching circuitry coupled to the electrical circuit and the cancellation circuit, the switching circuitry through which an input signal is coupled to the electrical circuit, is configured to generate a pilot signal applied to the electrical circuit for a period of time during which the cancellation circuit obtains information on adjustments made to its circuitry substantially without any interference from the input signal, and after said period of time has elapsed the cancellation circuit generates a distortion cancellation component in accordance with the adjustment information so as to reduce the distortion produced by the electrical circuit.
An automatic control system for reducing distortion comprising an amplifier that produces distortion and has an input and an output, the automatic control system comprising:
- a signal generator coupled to the input of the amplifier;
- a first feedback loop having a distortion output where said first feedback loop is configured to isolate the distortion at the distortion output;
- a feedforward circuit through which the distortion output is coupled to the output of the amplifier;
- a first switch coupled to the input of the amplifier;
- a second switch which couples the output of the amplifier to part of a second feedback loop;
- a pulse generator coupled to the switches and the signal generator, the first switch being configured to allow an input signal to couple therethrough to the input of the amplifier;
- and
- the pulse generator being configured to activate the switches and the signal generator for a period of time during which the first switch decouples the input signal from the input of the amplifier, the signal generator generates a pilot signal which is applied to the amplifier and the output of the amplifier is coupled through the second switch to the second feedback loop which obtains information on adjustments made to its circuitry substantially without any interference from the input signal and after the period of time has elapsed the feedforward circuit generates a distortion cancellation component based on the isolated distortion at the distortion output and in accordance with the adjustment information so as to reduce the distortion produced by the amplifier.
A method for controlling the distortion produced by an electrical circuit having an input and an output, the method comprises the steps of:
- applying an input signal to the input of the electrical circuit;
- decoupling the input signal from the electrical circuit for a period of time;
- applying, during the period of time, a pilot signal to the input of the electrical circuit,
- obtaining, during the period of time, adjustment information substantially without any interference from the input signal;
- reapplying the input signal to the input of the electrical circuit after the period of time has elapsed;
- isolating the distortion produced by the electrical circuit;
- generating a distortion cancellation component in accordance with the adjustment information;
- combining the distortion cancellation component with the output of the electrical circuit after the period of time has elapsed to reduce the distortion produced by the electrical circuit.
Dependencies are inferred from the claim text.