Glenayre Electronics, Inc.

Robert Richard Leyendecker

Claudio Gustavo Rey

Barry D Buternowsky

Edward J Anthony

Robert Addison Langridge, Jr

Glaudio Gustavo Rey

Desmond Wai Yan

Mihaela C Beluri

Jay Jui-Chieh Chen

Vladimir Pavlovic

Xavier Carbo Figueras

David Kent Bonds

Paul Andrew Goud

Derek Stephen Hilborn

David E Jones

Thomas L Frederick

Mark A Walker

Patricia Fern Kavanagh

Theron Lee Jones

Richard Johnathan Hinkle

Charles Brian Cox

David W Kroeger

Armando Cova Garrido

Desmond Wai Ming Yan

Terry Lee Hinkle

Wayne Douglas Duello

Joel Richard Dierks

Flaviu C Costescu

Ray Mr Sewlochan

Emre Tapucu

Yan Guo

A circuit for use in a two-way pager of a paging system to transmit voice messages. The circuit includes: a microphone to receive an analog audio signal provided by a user; an analog-to-digital (A-D) converter coupled to the microphone; a memory; a processor coupled to the memory and to the A-D converter; and a transmitter coupled to the processor. The analog audio signals are typically voice messages spoken by the user, which the A-D converter samples and digitizes. The processor stores the digitized voice message in the memory. The user can then transmit the stored digitized voice message through the transmitter, which is processed through the paging system and provided to the intended recipient. In a further refinement, the circuit includes a playback circuit that allows the user to listen to the stored digitized voice message before transmitting the voice message to the rest of the paging system.

Two-way communication device with transmission of stored signal directly initiated by user

A system for distributing voice information service messages (VISMs) to subscribers through their voice pagers is provided with a voice information service workstation where VISMs are recorded, and a voice information service terminal which converts the VISMs into voice pages and transfers them into a voice paging network for distribution to subscribers' voice pagers. The system may be accessed by subscribers via telephone, computer, or voice pager for changing personal settings.

Voice information service networking system

A two-way paging system includes one or more transmitters, a plurality of receivers, and at least one two-way personal paging unit or pager. The two-way pager receives pages from the transmitter, and sends response signals which are detected by the receivers. The response signals are in the form of digital packets, including forward error correction encoding and digital symbols that each consists of a predetermined number of bits. The receivers detecting the response signals decode the response packets to verify their accuracy and to identify the digital symbols. At the receivers, 'accuracy indicators' can be associated with the detected symbols, providing an indication of the probability of accuracy. In one embodiment ('microdiversity receiver') two receiver components are provided at a single receiver site, with a separate antenna for each receiver component. Signals as received at the different components can be compared and have the accuracy indication information combined to increase the reliability of the system in detecting and decoding the pager response symbols. A central controller receives information from several receivers and similarly processes and analyzes it to determine the most likely response signal sent by a pager.

Digital diversity receiver system

A system for linearly transmitting an amplified output signal using predistortion whereby a straight inverse modeling scheme is used to more easily and accurately determine the inverse of the distortion caused by a power amplifier of a RF transmitter. The 'inverse' of the power amplifier is directly modeled by considering the power amplifier as a signal processing block with the input and output ports reversed. As a result, the computationally intensive inversion required by conventional schemes is avoided. The predistorter system stores complex coefficients in a predistorter LUT, which are then used as the tap weights of a digital filter implementing the predistorter. The predistortion is done by a non-linear filter which incorporates both instantaneous and average envelope power or magnitude effects. The predistortion LUT is addressed as a function of the instantaneous envelope power or magnitude and past power or magnitude envelopes. This scheme takes into account the instantaneous envelope power or magnitude of the current sample and a profile of the envelope power or magnitude of previous samples to accurately compensate for modulation envelope memory effects of the power amplifier. The past powers or magnitudes provide an indication of the trajectory of the power or magnitude leading to the current power or magnitude, which enables the predistorter to more accurately compensate for the power amplifier distortion. The predistorter LUT is updated with values that are indexed as a function of the powers or magnitudes of past samples and the power or magnitude of the current sample.

Method and apparatus for linear transmission by direct inverse modeling

A system for linearly transmitting an amplified output signal using predistortion is disclosed. The system uses a straight inverse modeling scheme to more easily and accurately determine the inverse of the distortion caused by a power amplifier of a RF transmitter. The direct inverse modeling scheme of the present invention indexes the LUT using the modulated input signals instead of the potentially noisier output signals, which helps to increase the accuracy of the predistortion. The predistorter system stores complex coefficients in the LUT, which are then used as the tap weights of a digital filter implementing the predistorter. Finally, the trainer uses a modified version of the power amplifier output signal. The modified power amplifier output signal has the in-band distortion removed from the power amplifier output signal.

Frequency selective predistortion in a linear transmitter

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

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Blaine, WA, United States of America

Robert Richard Leyendecker