Abstract: A two-stage high-power RF limiter circuit for an RF signal receiver incorporates a heavy limiting stage to limit high energy pulses of a received RF signal to a desired power threshold over a sustained time period, while a light limiting stage reacts quickly to high energy pulses to reduce spike leakage associated with the slower reaction time of the heavy limiting stage. Both heavy and light limiting stages incorporate PIN diodes biased to a voltage just below the desired power threshold (the light limiter biased to a slightly higher voltage than the heavy limiter) so the PIN diodes do not activate until power levels are high enough to warrant limiting. The holdoff voltage across the PIN diodes is maintained by Zener diodes biased to a voltage corresponding to the power threshold, allowing the PIN diodes to self-bias once the power threshold is reached.

Abstract: A mobile radio has more than one channel, each channel corresponding to a programmable transceiver circuit. The mobile radio also includes at least one high gain antenna coupled to at least one of the programmable transceiver circuits. A location determining circuit is configured to determine the location of the mobile radio. A processor is coupled to the transceivers and to the location determining circuit. The processor runs a program logic that is configured to identify whether the mobile radio is in a location that enables the mobile radio to extend the reach of the network both due to its location and due to the use of the at least one high gain antenna. The processor also runs a program logic to carry out spectrum sensing to identify available spectral resources based on communication traffic on various frequency bands.

Abstract: A spread spectrum communication system includes a transceiver configured to transmit a spread spectrum waveform. The spread spectrum waveform comprises transmitted signals at varying frequencies within a radio frequency spectrum of operation. The frequency variation is controlled according to a hopping sequence. A spectral sensor of the communication system is configured to dynamically scan the radio frequency spectrum of operation and to generate channel occupancy data based upon the scans. A real time hopping sequence generator is configured to dynamically generate the hopping sequence in real time as a function of the channel occupancy data.

Abstract: The present invention is directed to a highly-integrated MEMS-based miniaturized transceiver. The transceiver utilizes a low band front-end to direct sample low band signals and a high band front-end to translate high band signals that cannot be directly sampled to low band before low band front-end processing. The low band front-end comprises an array of High-Q MEMS (microelectromechanical systems)-based filters/resonators separated by isolation amplifiers in selectable cascade with narrower bandwidth filters. Dynamic tuning ability is provided through the isolation amplifiers and the sample frequency of the analog-to-digital converter. This architecture is amenable to monolithic fabrication. The input frequency range is scalable with analog-to-digital conversion sampling rate improvements. Re-utilization of filters is spatially efficient and cost effective. Tuning time is limited only by the analog-to-digital conversion and digital signal processing, not synthesizer settling times.