Itt Manufacturing Enterprises, Inc.

William Ellis Rodgers

Bradley J Hamilton

Terrance Wayne Charbonneau

Richard Alan Kwolek

Bruce Alden Wight

A receiver includes a first oscillator supplying a reference frequency signal; a reference signal generator producing a first frequency conversion signal and a local calibration signal from the reference frequency signal; a first frequency converter responsive to the first frequency conversion signal to down-convert the received signal during normal receive operation and to down-convert the local calibration signal during calibration processing; a second frequency converter responsive to a second frequency conversion signal from a second oscillator to further down-convert the received signal and the local calibration signal; a demodulator that demodulates the received signal at a demodulation frequency; and a frequency error processor that determines a frequency error from the local calibration signal at the demodulation frequency, wherein the reference signal generator adjusts a frequency of the first frequency conversion signal used during normal receive operation in response to the frequency error to compensate for the frequency error.

Methods and apparatus for calibrating oscillators in a receiver

The invention includes a method of communicating in a network of multiple nodes transmitting and receiving messages to and from each other. The method includes (a) scanning in synchronism a receive directional beam of an antenna of a first node and a receive directional beam of an antenna of a second node; (b) steering, in azimuth, a transmit directional beam of an antenna of the first node to a relative bearing of the second node; and (c) transmitting a message from the first node to the second node, when the transmit directional beam of the first node and the receive directional of the second node are substantially aligned in relative bearing to each other.

Method of steering smart antennas

A technique for down converting signals from an Intermediate Frequency (IF) input signal to Inphase (I) and Quadrature (Q) signal samples at baseband replaces power-consuming A/D converters and AGC circuits with a low-cost zero-crossing comparator. The comparator converts the IF signal to a hard-limited signal having one value when the IF signal is positive and another value when the IF signal is negative. I and Q samples are generated by performing the equivalent of multiplication of the hard-limited signal by cos(2&#x3c0;fo*t) and sin(2&#x3c0;fo*t). By sampling the hard-limited signal at a rate that is an integer multiple of the intermediate frequency and an even number greater than or equal to four, multiplication by cos(2&#x3c0;f*t) and sin(2&#x3c0;f*t) required to generate I and Q baseband signal components is greatly reduced. The I and Q samples are summed (or integrated) by binary up/down counters over one bit duration and then dumped. The dumped counter outputs are estimates of the lowpass filtered I and Q signal components.

Methods and apparatus for downconverting signals from intermediate frequency to baseband

An Adaptive Position Transmission Algorithm (APTA) for mobile radio device where position information is required, using any transmission medium such as high frequency (HF), very high frequency (VHF), ultra high frequency (UHF), Satellite Communications (SATCOM), etc. A mobile radio device employing the APTA provides accurate and automatic position reporting and thus, in a tactical environment improves situation awareness and reduces the probability of fratricide. A mobile radio device employing the APTA also reduces the number of options available to the user thereby simplifying the operation thereof while improving overall performance in most applications. The APTA accomplishes this by monitoring position, time and radio network parameters to determine when stand alone messages will be transmitted. The APTA factors radio network loading with movement and periodic thresholds. As radio network loading increases, the movement and periodic thresholds are increased to reduce the impact of position reporting on the radio network. The APTA also incorporates a time limit which prevents the radio from transmitting too often. This time limit is based on radio network loading.

Mobile radio device having adaptive position transmitting capabilities

In a frequency hopping (FH) communication system comprising a plurality of radios operable in a first FH mode for transceiving information over a plurality of frequency channels corresponding to frequencies defining a frequency hop set, a method for adaptively selecting a single frequency channel within said hop set and transceiving said information over only said single frequency channel, said method comprising the steps of determining the quality of frequency hopping transmissions received at a receiving radio terminal in the first FH mode and providing a control signal when said quality is unacceptable; and operating the radio in a single frequency mode in response to the control signal when the FH transmission quality is unacceptable by transmitting the information over only a single frequency channel within the frequency hopping set which has an interfering energy level below a threshold value indicative of acceptable transmission quality.

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Fort Wayne, IN, United States of America

William Ellis Rodgers