Motorola Corporation

Asad U Aman

Thomas J Kundmann

Andrew Tomerlin

Gregory T Nash

Robert Stephens

Deepa Moorthy

A programmable modulator () is programmable to operate in either of a GMSK or 8PSK mode. When operating in a GMSK mode, a signal modulating circuitreceives () a bit stream (), maps the bit stream () to a phase value in complex I, Q form and applies a progressive rotation to the phase value according to GMSK specifications. The output () is filtered by a filter circuit (), preferably using a complex Finite Impulse Response (FIR) filter using the standard coefficients for an 8PSK modulation to create () an approximate GMSK output (). A GMSK correction circuit () determines a correction term that is added to the filter circuit output () so as to correct amplitude variations to allow the output to conform to GSM/EDGE standards. The same modulator () may be programmed to operate in an 8PSK mode with linear predistortion.

Apparatus and method for modulating and digitally predistorting a signal in a multiple modulation schemes

Multiple electrical signals (from, for example, multiple signal sources such as antennas) are converted by an electrical signal input () into corresponding optical signals. In one embodiment these electrical signals are comprised of temporally separated data elements. In this case, in a preferred embodiment, the optical signals mirror these temporal conditions. In addition, in a preferred approach, the optical signals are physically grouped such that temporally coincident data elements from each of the multiple electrical signals are positioned proximal to one another. The resultant optical signals are then correlated, in parallel, with a correlation reference () by an optical correlator lens (). In one embodiment, the optical signals are subjected to a Fourier transformation () and distorted () as necessary to normalize these resultant optical signals with the correlation reference (). The optical correlation then occurs in the Fourier domain.

Optical correlator system and supporting method and apparatus

A predistortion linear power amplifier utilizes several predistortion computation engines to receive a first carrier signal. The predistortion computation engines also receive input from a predistortion algorithm engine. The predistortion algorithm engine receives its data from a predistortion amplifier sensor that monitors the operating characteristics of the amplifier and also from a feedback control circuit that provides frequency correlated input and feedback data. The processed data from the predistortion algorithm engine is then input into the predistortion computation engine along with the carrier signal. An output combiner circuit takes the output of each predistortion computation engine and generates a single correction estimate, which is then input into the nonlinear amplifier for producing a substantially linear output signal.

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Schaumburg, IL, United States of America

Asad U Aman