Harris Corporation

William L Tyler

John Wesley Nieto

William Nelson Furman

James Anthony Norris

Richard Booton

Brian J Taylor

Timothy Snell

A communications device includes a demodulator configured to demodulate a received communications signal into complex time domain samples. A processor is coupled to the demodulator and configured to determine the variance over time domain magnitude samples, perform a complex Fast Fourier Transform (cFFT) on the complex time domain samples as magnitude and phase to obtain frequency domain samples and determine the variance over the frequency domain samples. A comparator compares a variance ratio of the time domain magnitude samples and the frequency domain samples with a threshold to determine if a RF interferer is present, indicative that the communications channel is busy.

Communications device and related method that detects radio frequency (RF) interferer on a communications channel

The communications device includes a phase and frequency tracking loop having a signal input and an adjustable loop filter that establishes a predetermined tracking loop bandwidth for samples of communication signals received at the signal input and processed within the tracking loop. A tracking loop update circuit updates loop filter operating parameters and is operative with the loop filter for increasing or decreasing the tracking loop bandwidth of the phase and frequency tracking loop based on the dynamics of the frequency offset of measured samples from the output of the loop filter over time.

Communications device using measured frequency offset over time to adjust phase and frequency tracking

A communications device includes a phase and frequency tracking loop having a signal input and adjustable loop filter that establishes a predetermined tracking loop bandwidth for samples of communication signals received at the signal input and processed within the tracking loop. A tracking loop update circuit updates the loop filter operating parameters. It is operative with the loop filter for increasing or decreasing the tracking loop bandwidth of the phase and frequency tracking loop based on the measured signal-to-noise ratio in the received samples of communication signals at the signal output by the tracking loop and on the known or measured apriori tracking capabilities of demodulator based on the symbol rate of communication signal.

Communications device using measured signal-to-noise ratio to adjust phase and frequency tracking

An improved method is provided for positioning a directional antenna coupled to a radio towards a satellite. The method includes: receiving an input to the radio from an operator of the radio, where the input indicates a desired time period for positioning the antenna; transmitting, during the desired time period, a plurality of burst data transmissions from the radio over a channel associated with the satellite; receiving a plurality of reply data transmissions from the satellite which correspond to the plurality of burst data transmissions sent by the radio; determining a metric indicative of signal quality for each of the reply data transmissions; and outputting from the radio an indicator for each metric. The operator of the radio can use the indicator output by the radio to better position the antenna towards the satellite.

Method for locating satellites using directional finding

A communications device includes a signal input for receiving signals such as a binary phase shift keyed (BPSK) communications signal having a repeated preamble bit or symbol pattern. A modem processes the communications signal and includes a demodulator and processor that generates an initial frequency offset estimate and phase error estimate by processing such as with a Fast Fourier Transform (FFT), that detects the repeated preamble pattern for a block of samples within the communications signal, correlates two halves of the block of samples with a plurality of different shifted sequences and determines a maximum correlation value for the shifted sequence that provides the maximum correlation value to establish a symbol timing estimate based on the known timing alignment of this shifted sequence. Radio circuitry is operative with the modem for processing communications data obtained from the communications signal.

Communications device and related method that detects symbol timing

A communications device includes a signal input for receiving signals such as a binary phase shift keyed (BPSK) communications signal having a repeated preamble bit or symbol pattern. A modem processes the communications signal and includes a demodulator and processor that generates an initial frequency offset estimate and phase error estimate by processing a Fast Fourier Transform (FFT) that detects the repeated preamble pattern for a block of samples within the communications signal, correlates within a start of message correlator to search for a start of message sequence and correlates different phases of the repeated preamble pattern within training correlators for reducing false detections of the start of message. Radio circuitry is operative with the modem for processing communications data obtained from the communications signal.

Communications device and related method with reduced false detects during start of message bit correlation

A repeated preamble bit or symbol pattern such as for a binary phase shift keyed (BPSK) communications signal is received within a modem. An initial frequency offset and phase error estimate is generated by processing a Fast Fourier Transform (FFT) that detects the repeated preamble pattern for a block of samples within the communications signal. Two halves of the block of samples are correlated with a plurality of different BPSK shifted sequences to obtain a symbol timing alignment based on the shifted sequence providing the maximum correlation value. A frequency offset estimate is iteratively updated an N number of times using the shifted sequence providing the maximum correlation value to refine an acquisition estimate of the frequency offset and phase error of the received communications signal.

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Rochester, NY, United States of America

William L Tyler