Transmitter Power Control Using Fast Envelope Gain Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing power control methods in communication terminals face inaccuracies due to variations in temperature, frequency, and supply voltage, leading to failures in meeting communication standards, especially at high power levels and in transmitters with switched power modes.
Innovation Solution
The method involves determining the envelopes of a communication signal at two measurement points in the transmission chain, computing the cross-correlation to find the actual gain, and adjusting the output power accordingly, eliminating the need for prior calibration and accounting for real-time operating conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional power control methods are used with fixed gain settings, then device complexity is reduced, but manufacturing precision deteriorates due to inaccuracies in meeting power control requirements under varying operating conditions
Solution Approach 1:
The system measures the actual gain of the transmission chain by comparing the envelope of the input signal with the envelope of the output signal, then uses this measured gain information to adjust the power amplifier gain setting, creating a closed-loop feedback control system that adapts to varying operating conditions
Solution Approach 2:
The transmission chain performs self-characterization by automatically measuring its own gain through envelope detection and cross-correlation of input and output signals, eliminating the need for external calibration equipment or pre-characterization procedures
2Manufacturing precision
If calibration procedures are performed to achieve accurate power control, then manufacturing precision is improved, but loss of time increases due to calibration requirements
Solution Approach 1:
The system performs self-characterization by automatically measuring its own gain through envelope detection and cross-correlation of input and output signals, eliminating the need for external calibration equipment or pre-characterization procedures
Solution Approach 2:
The system performs gain measurement and characterization during normal operation rather than requiring separate pre-calibration steps, so that power control accuracy is achieved without additional time-consuming calibration procedures
3Power
If high power levels are transmitted, then power output is improved, but reliability deteriorates due to non-linear distortion and failure to meet communication standards
Solution Approach 1:
The system continuously measures the actual gain of the transmission chain and uses this information to adjust the power amplifier settings, ensuring that the transmitted signal remains within linear operating regions and meets communication standard requirements even at high power levels
4Adaptability or versatility
If temperature and supply voltage variations occur, then adaptability is improved for different operating conditions, but manufacturing precision deteriorates due to gain variations
Solution Approach 1:
The system measures the actual gain of the transmission chain under current operating conditions by comparing input and output signal envelopes, then adjusts the power amplifier gain setting based on this measured information, compensating for temperature and supply voltage variations
Solution Approach 2:
The system dynamically adjusts the power amplifier gain setting based on real-time measurements of the transmission chain characteristics, allowing the system to adapt to changing operating conditions such as temperature and supply voltage variations
Data Source
AI summary
A method for controlling output signal power in a communication terminal includes determining envelopes of a communication signal to be transmitted by the communication terminal at respective first and second measurement points along a transmission chain in a transmitter of the terminal. A cross-correlation is computed between the envelopes determined at the first and second measurement points. An actual gain between the first and second measurement points is computed using the cross-correlation. An output power of the communication signal is adjusted by setting a gain of the transmitter responsively to the actual gain.