Motorola Corporation

Brian J Budnik

Michael D Kotzin

Steven Jeffrey Goldberg

Stephen Rocco Carsello

Douglas I Ayerst

George Francis Opas

Thomas A Sexton

Malik J Khan

James F Long

Arman V Dolikian

Armin V Dolikian

Donald Bryan Siperko

Douglas Irvin Ayerst

Base transmitters (116) of a wireless messaging system are pre-programmed (802) with location identifiers (216) for identifying the positions at which the base transmitters are located. In response to an inbound message from a portable subscriber unit (122), a fixed portion (102) of the wireless messaging system makes an estimate (808) of a location at which the portable subscriber unit is positioned. A controller (112) sends (812) an outbound message (614) and the estimate to the base transmitters, and the base transmitters calculate (812) distances between themselves and the portable subscriber unit, based upon the location identifiers and the estimate. In addition, the base transmitters independently make a decision (818) whether to transmit the outbound message, based upon a comparison of a predetermined rule with the distance of the base transmitter from the portable subscriber unit.

Method and apparatus in a wireless messaging system for dynamic creation

A variable-class linear amplifier (600, 800, 900) applies a supply type of envelope modulation to an RF power amplifier operating in or near compression at highest envelope amplitudes, and transitions gradually to an envelope tracking type of operation at intermediate envelope amplitudes. The amplifier further transitions gradually to a linear class of operation with a constant supply voltage (508) at lowest envelope amplitudes.

Method and apparatus for operating a radio-frequency power amplifier as

In a messaging system having a plurality of simulcasting base transmitters (104), a plurality of pseudorandom sequence generators (216) are provided (402) for the plurality of base transmitters. The plurality of pseudorandom sequence generators are arranged (403) to ensure that they generate a plurality of pseudorandom sequences having sub-sequences that are different from one another during concurrent transmissions by the plurality of base transmitters. A cancellation-affecting parameter of the plurality of base transmitters is adjusted (404, 406, 408) in accordance with the plurality of pseudorandom sequences during the simulcast transmission from the plurality of base transmitters to limit intervals of carrier cancellation.

Method and apparatus in a messaging system for limiting an interval of

An amplifier with adaptive output capacity allocation (201) including a processor (203), coupled to a signal, for examining the signal to determine a first capacity requirement and a second capacity requirement, and an amplifier (213), coupled to the processor and the signal, for processing the signal in accordance with the first capacity requirement and the second capacity requirement to provide an output signal thus maximizing power out of the amplifier given incoming signal conditions. A corresponding method of dynamically allocating spectral power in a transmitter having a peak power capability for transmitting information on a plurality of subcarriers during a plurality of predetermined sequential frame periods includes sampling the information (503) corresponding to a frame period to obtain a subcarrier envelope amplitude corresponding to each of the plurality of subcarriers; summing these subcarrier envelope amplitudes (505) to obtain a total envelope amplitude; examining the total envelope amplitude (507) to identify a maximum total envelope amplitude; and setting for the frame period a gain (509) in the transmitter such that the maximum total envelope amplitude substantially produces the peak power capability.

Amplifier with adaptive output allocation and method thereof

A method of providing compensation for distortion imparted to an input signal, principally by an amplifier (18), compares a delayed version of the input signal (34) to the amplifier's output signal. The result of the comparison is an error signal that is fed back to minimize distortion. This feedback technique is applied to a transmitter (10) in combination with predistortion that is selected to compensate for at least some of the distortion provided by the transmitter's output amplifier (18). The remainder of the compensation is provided by the error signal which can be generated by a relatively low gain analog feedback loop.

Method of compensating for distortion in an amplifier

A fixed system receiver (107), which includes a forward receiver (305), a reverse receiver (310), and a response timer (215), is for use in a radio communication system (100) having a forward radio channel and a reverse radio channel. A command is transmitted in a forward channel radio signal to a selective call transceiver. The forward receiver (305) is for receiving, demodulating, and decoding the command. The reverse receiver (310) is for receiving and demodulating the reverse channel radio signal. The response timer (215), which is coupled to the forward receiver (305) and the reverse receiver (310), is for determining a response period beginning substantially at a scheduled response time included in the command and having a duration which is substantially a designated length of the data unit included in the command, and for generating a control signal which enables the reverse receiver (310) during the response period.

Method and apparatus for improved message reception at a fixed system

The remote control system having symmetrical signaling circuits for radio communications is coupled to a single wire line/audio channel and permits two or more units, base stations and/or remote consoles, to be coupled to the single wire line. Each signaling circuit comprises a wire line coupler for coupling to the wire line, an audio input line and an audio output line. An automatic gain control circuit is coupled between the wire coupler and the audio output line and a filter and line driver are coupled between the audio input line and the wire coupler. A control unit including a microprocessor, a tone encoder, a tone decoder, a timer, a clock, and a memory is coupled by output lines to the automatic gain control circuit for controlling the modes of operation thereof which include a slow decay mode, a fast decay mode, an adapt mode and a hold gain mode. The output from the gain control circuit is also routed through a band pass filter and a limiter to the control unit. Further, the tone encoder of the control unit is coupled to a summing circuit situated between the filter and line driver through a filter and level control circuit. The protocol programmed in the microprocessor enables any unit to take control of the audio channel by initiating the sending of a message. Also mute gates are provided for disabling audio output or audio input while a message is being sent or received over the audio channel.

Remote control system having symmetrical tone, send/receive signaling

Automatic gain control for a remote control system having symmetrical

Improved control circuitry for pulse-width-modulated power supplies is described that includes a pulse generator for generating a train of trigger pulses at a predetermined repetition frequency, a signal source for generating a reference voltage and a comparator for comparing the power supply output voltage to the reference voltage and generating a first state of a switching control signal in response to each trigger pulse from the pulse generator and a second state of the switching control signal when the magnitude of the power supply output voltage is equal to the magnitude of the reference voltage. The first state of the switching control signal enables switching transistors of the switching power supply, and the second state of the switching control signal disables the switching transistors. The comparator also includes circuitry for reducing the magnitude of the reference voltage when the switching control signal has the second state. Thus, once the switching transistors are disabled by the second state of the switching control signal, the magnitude of the reference voltage is reduced by a predetermined amount so that the switching transistors cannot be re-enabled until the next trigger pulse from the pulse generator causes the switching control signal to change states.

Control circuitry for a pulse-width-modulated switching power supply

The invention is a controlled ferroresonant power supply with an improved feedback circuit resulting in improved output stability. The feedback circuit is responsive to the low voltage secondary output of the power supply to provide a variable output signal to activate the switch which controls the resonant winding circuit. The improved feedback circuit is responsive to the rectified AC low voltage secondary output for only a portion of its frequency period.

Controlled ferroresonant voltage regulator providing immunity from

A stabilization circuit is provided for use with a ferroresonant power supply to maintain a steady output voltage during power line transients, rapid load changes, or no load condition. The stabilization circuit is responsive to the voltage output of the power supply and selectively connects a load across voltage output terminals. Stabilization circuit includes a voltage sensing circuit that enables a timing circuit that activates a switch to place the load across terminals. This stabilizes the power supply, without requiring a continuously dissipative minimum load.

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Schaumburg, IL, United States of America

Brian J Budnik