Abstract: Various embodiments disclosed herein enable steerable, time division duplex (“TDD”) communications channels at millimeter-wave frequency bands. Among other things, embodiments disclosed herein provide improved steering accuracy and power distribution, lower power consumption, and potentially longer service life than previous transceiver systems.

Abstract: A combined proximity monitoring and locating system including a wearable unit, a proximity detector, and a control subsystem. The proximity detector includes a receiver for receiving the wearable unit transmitter signal, a processing subsystem configured to signal an alert if the wearable unit transmitter signal strength is below a pre-established minimum, and a tracking subsystem configured to assist in locating the wearable unit based on the signal strength of the wearable unit transmitter signal. A control subsystem is responsive to an indication that the alert has been signaled. The control subsystem includes an RF transmitter configured to transmit a transponder activation signal, and an RF antenna network for relaying the transponder activation signal to a receiver of the portable unit to activate the transponder thereof. A tracking unit includes a receiver configured to receive the transponder signal of the wearable unit to locate the wearable unit.

Abstract: An asset location, tracking, and recovery system and method includes a network of VHF towers and a control center receiving signals from and transmitting signals to the VHF towers. Primary locating units each include a transmitter, a receiver, and a transponder activated when a signal is transmitted by the control center via the VHF towers to the receiver. Auxiliary locating units include at least a transmitter emitting a signal received by at least one primary locating unit receiver which relays that signal to the control center via the VHF towers from the primary locating unit transmitter.

Abstract: A system for wireless communications includes a tower structure supporting at least one transmit antenna at an elevated position on the tower structure and base electronics positioned proximate a base of the tower structure. The base electronics are coupled with the transmit antenna and include an initial stage amplifier for amplifying an input signal to provide a low power transmission signal that is provided to the transmit antenna at the elevated position. A final stage amplifier is positioned proximate the transmit antenna. The final stage amplifier is a high efficiency amplifier for efficiently amplifying the low power transmission signal from the base electronics to provide a high power transmission signal to be transmitted from the transmit antenna.

Abstract: A combined proximity monitoring and locating system including a wearable unit, a proximity detector, and a control subsystem. The proximity detector includes a receiver for receiving the wearable unit transmitter signal, a processing subsystem configured to signal an alert if the wearable unit transmitter signal strength is below a pre-established minimum, and a tracking subsystem configured to assist in locating the wearable unit based on the signal strength of the wearable unit transmitter signal. A control subsystem is responsive to an indication that the alert has been signaled. The control subsystem includes an RF transmitter configured to transmit a transponder activation signal, and an RF antenna network for relaying the transponder activation signal to a receiver of the portable unit to activate the transponder thereof. A tracking unit includes a receiver configured to receive the transponder signal of the wearable unit to locate the wearable unit.

Abstract: An asset location, tracking, and recovery system and method includes a network of VHF towers and a control center receiving signals from and transmitting signals to the VHF towers. Primary locating units each include a transmitter, a receiver, and a transponder activated when a signal is transmitted by the control center via the VHF towers to the receiver. Auxiliary locating units include at least a transmitter emitting a signal received by at least one primary locating unit receiver which relays that signal to the control center via the VHF towers from the primary locating unit transmitter.

Abstract: A system for wireless communications includes a tower structure supporting at least one transmit antenna at an elevated position on the tower structure and base electronics positioned proximate a base of the tower structure. The base electronics are coupled with the transmit antenna and include an initial stage amplifier for amplifying an input signal to provide a low power transmission signal that is provided to the transmit antenna at the elevated position. A final stage amplifier is positioned proximate the transmit antenna. The final stage amplifier is a high efficiency amplifier for efficiently amplifying the low power transmission signal from the base electronics to provide a high power transmission signal to be transmitted from the transmit antenna.

Abstract: A low cost, high performance near direct conversion FM receiver having a single local oscillator is configured to equalize in-phase and quadrature-phase IF signals. The receiver includes a downconverter and a processor. The downconverter receives an RF signal and downconverts the RF signal to an in-phase IF signal (IF.sub.I) and a quadrature-phase IF signal (IF.sub.Q). The processor digitizes IF.sub.I and IF.sub.Q, corrects these signals so that they are substantially equal in magnitude and substantially 90.degree. out of phase, and then downconverts the IF signals to baseband signals (I, Q).

Abstract: The present invention relates to circuitry for a receiver having a low cost filter using automatic alignment of the center frequency of signals input to the filter to suppress noise and out-of-band signals from the filter output over a narrow bandwidth. An RF input signal to the receiver is downconverted to an IF frequency using a VCO, and the IF signal is provided to the low cost filter. The output of the filter is input to a frequency correction circuit and a distortion detection circuit. The distortion detection circuit provides an error signal including positive frequency shift errors determined from digital ones identified from the filter output signal, and negative frequency shift error signals determined from digital zeros in the filter output signal.

Abstract: Methods and apparatus for digital cordless telephone systems are preferably implemented in an integrated circuit chip set having one or more chips, adapted to receive a voice signal, for converting the voice signal into a digital signal of a desired form, for converting the digital signal into an analog signal and for modifying the frequency of the analog signal, for up converting during transmission the frequency of the analog signal from an intermediate frequency to a desired radio frequency and for down converting during reception from a selected radio frequency to the intermediate frequency and for amplifying the radio frequency signal during transmission and for switching the antenna between the transmit and receive paths. It is preferred for the chip set to include a base chip, an intermediate frequency chip, a radio frequency chip and an amplifier chip.

Abstract: An integrated circuit chip set is provided for use in a radio communication system in which a modulated digital input signal is processed for transmission and a modulated signal received from an antenna is processed to provide an output signal, wherein the modulation of the signals is either QPSK or FSK and the signal transmission and reception is by either TDD or FDD.

Abstract: Methods and apparatus for frequency synthesization are shown for generating an output signal of desired frequency. The frequency synthesizer includes an oscillator for generating an output signal at the desired frequency in response to a control signal. A first detector compares the output signal to a reference signal and generates a first difference signal representative of the differences, preferably in phase and frequency, between the output and the reference signals. A second detector compares the output signal to the reference signal and generates a second difference signal. A controller generates the control signal in response to either the first or second difference signal. A selector member selects between the first and second detectors to provide either the first or second control signal to the controller in response to a selection signal.