Abstract: A direction finding system for finding the angle of arrival of a target signal from a transmitter. The system includes a plurality of directional antennas positioned to face different directions for receiving the target signal. The antennas are mounted as an antenna array on a rotatable mount for supporting and rotating the antenna array. A receiver unit down converts the RF target signal to IF signals that are digitized by an A/D converter providing digital values. A computer computes the power in the signals from the A/D samples. A computer stores calibration information for the directional antennas, processes the digital values and the calibration information to determine a rotation angle ? for rotating the antennas to provide new digital values, processes the new digital values and the calibration information to determine an intersection angle, and subtracts the rotation angle from the intersection angle to determine the final value for the angle of arrival of the target signal.

Abstract: A direction finding system for finding the angle of arrival of a target signal from a transmitter. The system includes a plurality of directional antennas positioned to face different directions for receiving the target signal. The antennas are mounted as an antenna array on a rotatable mount for supporting and rotating the antenna array. A receiver unit down converts the RF target signal to IF signals that are digitized by an A/D converter providing digital values. A computer computes the power in the signals from the A/D samples. A computer stores calibration information for the directional antennas, processes the digital values and the calibration information to determine a rotation angle ? for rotating the antennas to provide new digital values, processes the new digital values and the calibration information to determine an intersection angle, and subtracts the rotation angle from the intersection angle to determine the final value for the angle of arrival of the target signal.

Abstract: An airborne jammer for transport by an aircraft for jamming communications in a communications system where the communications system operates with digital bursts having burst periods measured in time and occurring in a communication frequency band such as GSM having a transmit band and a receive band. The jammer includes a tone comb generator for providing repetitions of jamming signals for the communication frequency band where the jamming signals have jamming signal intervals providing frequency separation between the jamming signals. The jamming signals are generated with a dwell time substantially less than a burst period for the communications system. The jamming signals are transmitted as RF jamming signals to jam communications for mobile stations.

Abstract: An airborne jammer for transport by an aircraft for jamming communications in a communications system where the communications system operates with digital bursts having burst periods measured in time and occurring in a communication frequency band such as GSM having a transmit band and a receive band. The jammer includes a tone comb generator for providing repetitions of jamming signals for the communication frequency band where the jamming signals have jamming signal intervals providing frequency separation between the jamming signals. The jamming signals are generated with a dwell time substantially less than a burst period for the communications system. The jamming signals are transmitted as RF jamming signals to jam communications for mobile stations.

Abstract: A jammer for jamming communications in a communications system where the communications system operates with digital bursts having burst periods measured in time and occurring in a communication frequency band such as GSM having a transmit band and a receive band. The jammer includes a tone comb generator for providing repetitions of jamming signals for the communication frequency band where the jamming signals have jamming signal intervals providing frequency separation between the jamming signals. The jamming signals are generated with a dwell time substantially less than a burst period for the communications system. The jamming signals are generated concurrently for the transmit band and the receive band and are transmitted as RF jamming signals to jam communications for mobile stations.

Abstract: The subject of this patent is a system to generate RF frequency hopped signals that can be used to test radio receivers over the range of their signal specifications. The hop sequence and symbols in the signal is decoded from signals transmitted by the same or different radio of the same specification. The system can set various signal parameters to any prescribed value. These parameters include carrier frequency error, bit rate error, rise and fall times, amplitude ripple and roll off, modulation depth, nonlinearities, burst duration, burst start time and burst interval. Signal interference can be added to the signal including tones, other signals, noise and other signals of the same as the test radio. Similarly other communications equipment can be tested by the combination of receiving and demodulating a transmitted and regenerating the signal with the same symbols with specified signal parameters.

Abstract: A jammer for jamming communications in a communications system where the communications system operates with digital bursts having burst periods measured in time and occurring in a communication frequency band such as GSM having a transmit band and a receive band. The jammer includes a tone comb generator for providing repetitions of jamming signals for the communication frequency band where the jamming signals have jamming signal intervals providing frequency separation between the jamming signals. The jamming signals are generated with a dwell time substantially less than a burst period for the communications system. The jamming signals are generated concurrently for the transmit band and the receive band and are transmitted as RF jamming signals to jam communications for mobile stations.

Abstract: A jammer for generating and transmitting RF broadband jamming signals for jamming one or more local RF receivers. The jammer includes a broadband antenna unit for receiving broadband RF jammer received signals from local transmitters and for transmission of regenerated broadband RF jamming signals to the local receivers. The jammer uses a plurality of jamming algorithms including a regeneration algorithm and one or more alteration algorithms that alter the regenerated signals whereby the altered regenerated signals are asynchronous with respect to ones of, or all of, the jammer received signals. The alteration algorithms include a chopping algorithm and an FM modulation algorithm.

Abstract: A jammer for generating and transmitting RF broadband jamming signals for jamming one or more local RF receivers. The jammer includes a broadband antenna unit for receiving broadband RF jammer received signals from local transmitters and for transmission of regenerated broadband RF jamming signals to the local receivers. The jammer uses a plurality of jamming algorithms including a regeneration algorithm and one or more alteration algorithms that alter the regenerated signals whereby the altered regenerated signals are asynchronous with respect to ones of, or all of, the jammer received signals. The alteration algorithms include a chopping algorithm and an FM modulation algorithm.

Abstract: A signal analyzer to characterize the RF signal transmitted by a frequency hopping radio transmitter. The transmitted signal is analyzed while hopping across a broad frequency band without knowledge of the hop frequencies, timing or signal bandwidth. A wide range of signal parameters are measured on the dehopped signal to characterize the radio performance and the compliance to the radio specifications.

Abstract: A digitally controlled angle noise signal generator for generating a signal with precise and accurate noise. The signal generator is formed of a digital noise generator for generating a digital noise signal &thgr;N, and a digital signal generator for forming an internal signal S. The digital signal generator receives the digital noise signal &phgr;N and modulates the internal signal S with the digital noise signal &phgr;N to generate a digitally controlled signal yg=S{&thgr;N}, where is the modulation operator, with precise and accurate noise.

Abstract: A digitally controlled angle noise signal generator for generating a signal with precise and accurate noise. The signal generator is formed of a digital noise generator for generating a digital noise signal &thgr;N, and a digital signal generator for forming an internal signal S. The digital signal generator receives the digital noise signal &phgr;N and modulates the internal signal S with the digital noise signal &phgr;N to generate a digitally controlled signal yg=S{&thgr;N}, where is the modulation operator, with precise and accurate noise.

Abstract: Validating identification clusters formed of unique transmitter intercepts and validating clusters based on information within the cluster data with or without the aid of specific intercepts. Transmitter validation signals are allocated for validating specific ones of the transmitters. Analyzers identify specific received intercepts from specific ones of the transmitters to form an identification signal. Storage is provide for storing the specific received intercepts with corresponding identification clusters for marking the specific identification cluster as validated or invalidated. The valid and invalid states of the stored clusters are used to authorize or prevent access by the transmitters to the communication system.