Glenayre Electronics, Inc.

Paul Andrew Goud

Richard Johnathan Hinkle

Charles Brian Cox

David W Kroeger

Claudio Gustavo Rey

Todd A Stewart

Robert F Marchetto

Robert Richard Leyendecker

David Kent Bonds

Thomas L Frederick

David E Jones

Mark A Walker

Derek Stephen Hilborn

Patricia Fern Kavanagh

Timothy Jay Linderer

Michael J McCabe

Jay Jui-Chieh Chen

Vladimir Pavlovic

Theron Lee Jones

Terry Lee Hinkle

Wayne Douglas Duello

Joel Richard Dierks

Flaviu C Costescu

Robert J Shade

Ray Mr Sewlochan

Emre Tapucu

Tony Lung Chan

Roderick David Filer

Kyle Jackson Drewry

Lee I Williams

A method and apparatus for on-the-fly mode change in a paging system (201) is provided. A transmitter controller (301) in a base station (207) receives paging information. From the paging information, the transmitter controller (301) is capable of identifying a plurality of paging protocols associated with the paging information. Each identified paging protocol is associated with a corresponding mode. Mode information (D.sub.3, D.sub.4) corresponding to each mode is provided to an exciter (303). Based upon the mode information, the exciter (303) modulates a frequency using predetermined values of frequency deviation and frequency offset associated with the mode. The exciter (303) produces a modulated signal that transitions from one mode to another without delay.

Method and apparatus for on-the-fly mode change in a paging transmitter

A transmitter includes a modulator, a power amplifier and a controller to reduce the effects of phase cancellation in a simulcast paging system. The modulator is digitally configurable to modulate according to at least two protocols. The controller configures the modulator for a first protocol and provides to the modulator a signal to be broadcast. The modulator then modulates this signal according to the first protocol and causes the modulator to introduce a random frequency offset within a frequency range predetermined to optimally reduce phase cancellation for the first protocol. When the controller provides a signal to be broadcast according to a second protocol, the controller reconfigures the modulator for the second protocol. In addition the controller causes the modulator to introduce a random frequency offset within a predetermined range to optimally reduce phase cancellation for the second protocol. Because the controller can change the frequency offset on a protocol basis, phase cancellation errors can be optimally reduced for both protocols. In addition, the transmitter can easily be reconfigured to support new protocols as they are developed without changing the existing transmitter hardware. Still further, the randomly changing offsets dispense with the need to maintain records of the offsets for each transmitter in the simulcast paging system.

Method and apparatus for reducing phase cancellation in a simulcast

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 digital exciter (30) for selectively modulating digital or analog input data. The digital exciter includes a digital signal modulator (32) and a digital quadrature modulator (DQM)(36) comprising two digital signal processors (DSPs). The signal modulator is controlled by a control (40). An operator can selectively determine whether the digital exciter is used for modulating either two level or four level NRZ digital data and whether the device is to provide linear modulation or frequency modulation (FM) of the input signal. An interpolator (38) interpolates a 662/3 kHz timer interrupt rate used in the signal modulator to a 400 kHz rate, thereby reducing the processing load on the DSP comprising the DQM by simplifying the sine and cosine values used in the quadrature modulation. An operator can select from among a plurality of operating parameters on a menu for controlling the signal modulator, either from a local or a remote video display terminal (VDT).

Digital signal processor exciter

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Coquitlam, Canada

Paul Andrew Goud