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 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: Apparatus for identifying wireless subscriber units and for determining if access to a communications network should be granted. A plurality of wireless subscriber units each generates a wireless subscriber signal including internal data traits and external signal traits. The internal data traits include an identification code. A RF downconverter is located remote from the wireless subscriber units and receives the wireless subscriber signal. A characterizing device is connected to the RF downconverter and extracts parameters that characterize the external signal traits of the wireless subscriber units. A decision device computes the likelihood that the observed parameters belong to the validated wireless subscriber unit to determine if access to the wireless subscriber service should be granted. The apparatus may be used to prevent cellular telephone cloning fraud.

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.