Transmitter structure for communications systems

Abstract

Transmitter architectures for a communications system having improved performance over conventional transmitter architectures. The improvements include a combination of the following: faster responsetime for the control signals, improved linearity, reduced interference, reduced power consumption, lower circuit complexity, and lower costs. For a cellular application, these improvements can lead toincreased system capacity, smaller telephone size, increased talk and standby times, and greater acceptance of the product. Circuitry is provided to speed up the response time of a control signal. The control loop for various elements in the transmit signal path are integrated. A gain control mechanism allows for accurate adjustment of the output transmit power level. Control mechanisms are provided to power down the power amplifier, or th e entire transmit signal path, when not needed. The gains of the various elements in the transmit signal path are controlled to reduce transients in the output transmit power, and to also ensure that transients are downward.

Description

[0001] This application is a divisional application of the patent application with application number 01808125.8, date of application is March 2, 2001, and title of invention is "Transmitter Structure of Communication System". technical field [0002] This invention relates to electronic circuits in communication systems, and more particularly to transmitter structures providing improved performance. Background technique [0003] Various design considerations make the design of high performance transmitters challenging. For many applications, high performance is required to meet system specifications. High performance can be characterized by the linearity of the transmit signal path, wide dynamic range for controlling transmit power, and other characteristics. Also, for some applications, such as cellular communication systems, power consumption is an important consideration due to the portable nature of cellular telephones. Cost is also a major consideration for many tran...

AI Technical Summary

Problems solved by technology

[0005] In CDMA communication systems, non-linearity generation in the transmitter manifests itself as intermodulation distortion and degrades system performance

To reduce non-linearity, components in the transmit signal path are designed to operate within their linear range, resulting in large power consumption

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