US 2019/0058499 A1 · COMPLEMENTARY AUTOMATIC GAIN CONTROL FOR ANTI-JAM COMMUNICATIONS

Abstract

Anti-jamming techniques are provided for RF receivers, such as those that operate in hostile environments. In some embodiments, the techniques are embodied in an anti-jam communications system configured with automatic gain control (AGC) that is complementary. The system includes a first AGC circuit prior to an interference suppression circuit and a second AGC circuit after the interference suppression circuit. The first AGC circuit operates to adjust the power level presented to the interference suppression circuit to facilitate interference cancellation. The second AGC circuit operates to maintain the original power level of the desired communications signal and prevent amplitude errors as the first AGC circuit responds to fluctuations in jammer signal power. The second AGC can be slaved to the first AGC circuit such that the sum of two gain values is held constant, according to some embodiments. In this manner, the first and second AGC circuits provide a complementary-AGC system.

Claims20

Dependent claims

An anti-jam communications system, comprising:

a first automatic gain control (AGC) circuit having an input to receive RF signals captured by an antenna, and an output to provide a first gain adjusted version of the received RF signals, the received RF signals including a desired signal and a jammer signal;
an interference suppression circuit having an input to the first gain adjusted version of the received RF signals, and to suppress the jammer signal, thereby providing a second gain adjusted version of the received RF signals;
and
a second AGC circuit having an input to receive the second gain adjusted version of the received RF signals, and an output to provide a third gain adjusted version of the received RF signals;
wherein the sum of the gain provided by the first AGC circuit and the gain provided by the second AGC is within the range of −1.0 dB to +1.0 dB.

2 more elements

An anti-jam communications system, comprising:

a first automatic gain control (AGC) circuit having an input to receive RF signals captured by an adaptive antenna array, and an output to provide a first gain adjusted version of the received RF signals, the received RF signals including a desired signal and a jammer signal, wherein the first AGC circuit includes
a first variable gain amplifier having a gain that is adjustable based on a first analog control signal;
a sampling circuit to generate a representation of the first gain adjusted version of the received RF signals;
and
a first control circuit to receive the representation of the first gain adjusted version of the received RF signals and to provide the first analog control signal to the first variable gain amplifier;
an interference suppression circuit having an input to the first gain adjusted version of the received RF signals, and to suppress the jammer signal, thereby providing a second gain adjusted version of the received RF signals;
and
a second AGC circuit having an input to receive the second gain adjusted version of the received RF signals, and an output to provide a third gain adjusted version of the received RF signals, wherein the second AGC circuit includes
a second variable gain amplifier having a gain that is adjustable based on a second analog control signal;
and
a second control circuit to receive the first analog control signal and to provide the second analog control signal to the second variable gain amplifier, the second analog control signal being substantially complementary to the first analog control signal;
wherein gain provided by the first AGC circuit is substantially complementary to gain provided by the second AGC circuit.

9 more elements

An anti-jam communications system, comprising:

a first automatic gain control (AGC) circuit having an input to receive RF signals captured by an adaptive antenna array, and an output to provide a first gain adjusted version of the received RF signals, the received RF signals including a desired signal and a jammer signal, wherein the first AGC circuit includes
a first variable gain amplifier having a gain that is adjustable based on a first digital control signal;
a sampling circuit to generate a representation of the first gain adjusted version of the received RF signals;
and
a first control circuit to receive the representation of the first gain adjusted version of the received RF signals and to provide the first digital control signal to the first variable gain amplifier;
an interference suppression circuit having an input to the first gain adjusted version of the received RF signals, and to suppress the jammer signal, thereby providing a second gain adjusted version of the received RF signals;
and
a second AGC circuit having an input to receive the second gain adjusted version of the received RF signals, and an output to provide a third gain adjusted version of the received RF signals, wherein the second AGC circuit includes
a second variable gain amplifier having a gain that is adjustable based on a second digital control signal;
and
a second control circuit to provide the second digital control signal to the second variable gain amplifier, the second digital control signal being substantially complementary to the first digital control signal;
wherein gain provided by the first AGC circuit is substantially complementary to gain provided by the second AGC circuit.

9 more elements

Dependencies are inferred from the claim text.

Complementary automatic gain control for anti-jam communications

Life of this patent

Complementary automatic gain control for anti-jam communications

Life of this patent

Abstract

Claims20