Motorola Corporation

Sierra Wireless, Inc.

Sonic Systems, Inc.

Other

Unity Wireless Systems Corporation

Peter Robert McConnell

Robert Allan Scragg

Patricia Fern Kavanagh

Michael Rodney Walker

A coded siren sound generator and a corresponding detector module are provided which allow uniquely coded tone patterns generated by the coded siren to be detected and processed such that only specific sirens will activate the detector module. In one embodiment, only a few codewords are sent by the transmitter. The receiver looks for the occurrence of one or more of these selected codewords and takes a predetermined action based on programming of the detector. The system may operate at audible or ultrasonic frequencies. In accordance with a further embodiment, audio (either audible or ultrasonic) 'packets' are sent by the transmitter These packets contain sufficient information to uniquely identify the vehicle sending the packet and allow the vehicle to send commands and data to the detector. The commands and data may be for purposes such as requesting emergency pre-emption for a left turn at an intersection, requesting straight ahead pre-emption, etc.

Control signal coding and detection in the audible and inaudible ranges

The present invention, generally speaking, provides an acoustic railway crossing detector. The present invention provides a means of not only detecting the presence of a train, but it can determine speed and direction of travel. This allows a more adaptive control of the railway crossing gates and may reduce the nuisance factor of having the gate close too far in advance of the train reaching the crossing. It is also much less susceptible to false activation by natural causes or acts of vandalism. In accordance with one embodiment of the invention, an acoustic railway crossing detector includes at least one acoustic emitter; at least one acoustic detector; multiple reflectors arranged to reflect acoustic energy produced by an acoustic emitter toward an acoustic detector, and control circuitry coupled to an acoustic detector for producing an indication of whether or not a train is present.

Audio railway crossing detector

A improved siren detector for detecting siren sounds which precess at known warble rates, such as yelp, wail, and high-low, within a selected frequency band. A transducer detects the siren sounds and produces a corresponding electrical output signal. This electrical output signal is filtered to reject signals outside of the selected siren frequency band. The signal is processed to determine the amplitude of the electrical signal, and hence the sound level of the siren sound at the transducer input. This signal is also processed by an amplitude limiter and frequency discriminator to determine the instantaneous frequency of the siren sound. This discriminator is followed by a non-linear filter to remove the FM clicks characteristic of siren sounds having a low signal to noise ratio. Selection filters are used to analyze the precession rates, maximum frequency, minimum frequency, and shape of the precession characteristic to classify the siren as to its type, such as yelp, wail, and high-low. A sound which meets the selection criteria and has a sound level above a predetermined threshold causes the siren detector to trigger signal which drives a preempt output. This preempt output signal is input to a traffic light control system. This alerts the traffic light control system to control the Pedestrian Walk/Don't Walk and traffic lights to cause pedestrians to clear the intersection and to provide a preemptive traffic control signal to a vehicle equipped with the appropriate siren.

Siren detector

Modem throughput across a cellular mobile telephone network is increased by controlling the response of the modem to blank and burst orders. In the case of a power control order, the modem may be made aware of the fact that the channel has not changed. Significant performance gain in terms of channel throughput can then be achieved by avoiding a lengthy retraining procedure. The modem operation may be suspended during the blank and burst order and enabled after the blank and burst order, avoiding an unnecessary retrain procedure during the blanking period. In the case of a handoff, the modem may be directed to immediately perform a retrain procedure rather than wait for the long blanking period to be detected by the modem or the link access procedure.

Method and apparatus for decreasing modem retraining due to blank and

A dual port frequency modulator and method for eliminating the undesired affects caused by high port/low port phase differences in a standard dual port frequency modulator. The frequency modulator includes an inverse filter stage coupled to the input of a modulator stage including a first high port processing path for processing high frequency components of a modulation signal and a second low port processing path for processing low frequency components of a modulation signal. The outputs of the high and low paths are coupled to separate ports of a voltage controlled oscillator. The impulse response of the inverse filter is designed to be the inverse of the impulse response of the modulator stage. The filter functions to counter-act the adverse effects caused by the delay difference in the high and low processing paths of the modulator stage such that the overall response of the dual port frequency modulator is significantly improved.

Fixed compromise equalization for a dual port FM modulator

An apparatus and method for significantly increasing the coding gain of a system used for data communications while still maintaining a high code rate (net data rate/gross data rate) and throughput by using a concatenated coding arrangement wherein error correction capabilities are optimized, having an encoder for encoding data to be transmitted with a first code type to form an outer code which is capable of correcting burst errors and further detecting if the remaining data is error free, and for encoding the data and the outer code with a second code type to form an inner code which is capable of correcting random errors and detecting multiple bit errors.

Concatenated coding method and apparatus with errors and erasures

An arrangement for high speed data detection and clock recovery in a multi-level data signal is disclosed wherein the received signal wavform is sampled at periodic preselected locations and the samples so obtained are compared to set values representing the expected levels at those locations. In within a permitted tolerance range over a given window of time, an indication of the presence of data is determined. Futher, if such correlation is determined to occur at a periodic rate, symbol-timing (clock) recovery is also indicated. A further embodiment with a dual recovery capability is also disclosed and described.

High Speed data detection and clock recovery in a received multi-level

A communication system utilizing a plurality of receiving antenna which receive digital signals and process all of the received signals in the same trellis type decoder. Hamming weights are applied to each of the signals in accordance with the Viterbi algorithm with only the minimum Hamming weight for any one state transition path between any two levels in the trellis being retained. At the intersection of any two paths in the trellis, the path with the minimum Hamming weight is retained and the other path is discarded.

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Burnaby, Canada

Peter Robert McConnell