Glenayre Electronics, Inc.

Sonic Systems, Inc.

Patricia Fern Kavanagh

Claudio Gustavo Rey

Peter Robert McConnell

Robert Richard Leyendecker

David Kent Bonds

Mohammad Aamir Husain

Paul Andrew Goud

Thomas L Frederick

David E Jones

Bhaskar Bhattacharya

Mark A Walker

Derek Stephen Hilborn

Jay Jui-Chieh Chen

Charles Brian Cox

Vladimir Pavlovic

David W Kroeger

Theron Lee Jones

Richard Johnathan Hinkle

Joel Richard Dierks

Flaviu C Costescu

Ray Mr Sewlochan

Emre Tapucu

Terry Lee Hinkle

Wayne Douglas Duello

A method and apparatus for reducing peak-to-average power ratio in a paging transmitter broadcasting an independent sideband amplitude modulation protocol is disclosed. A digital signal, for example a digital voice signal, is provided to a control gain generator which generates a digital gain sequence. The digital gain sequence is such that during peak values in the digital signal the gain is low and during low values in the digital signal the gain is high. The digital gain sequence is multiplied with the digital signal to compress the dynamic range of the digital signal.

Method and apparatus for peak-to-average ratio control in an amplitude

A linear transmitter (101) using predistortion includes a modulator (103), a predistorter (107), a digital quadrature modulator (111), an upconverter (113), a power amplifier (115), and an antenna (117). In addition, the transmitter (101) has a feedback loop including a coupler (119), a downconverter (123), a digital quadrature demodulator (125), and a trainer (131). The digital data to be transmitted is provided into the modulator (103), which converts the digital data into in-phase and quadrature component signals. The in-phase and quadrature component signals are then provided to the predistorter (107), which 'predistorts' the component signals prior to amplification. The digital quadrature modulator (111) converts the component signals into a single analog signal. The upconverter (113) upconverts this signal from the predistorter (107) into the desired frequency of transmission, which is provided to the power amplifier (115) and the antenna (117) for amplification and broadcast. The coupler (119) provides a portion of the amplified signal to the analog downconverter (123), which lowers the frequency of this signal to a range that is easily processed. The signal is then provided to the digital quadrature demodulator (125), which outputs the in-phase and quadrature component signals of the signal. These in-phase and quadrature component signals are provided to the trainer (131) which analyzes them with the output signals from the modulator. The trainer (131) compares these signals and updates the predistorter (107) so that the digital quadrature demodulator (125) output signals are substantially equivalent to the modulator (103) output signals.

Linear transmitter using predistortion

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

Growing community of inventors

Burnaby, Canada

Patricia Fern Kavanagh