Communication System IQ Mismatch Calibration
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In-phase and quadrature-phase mismatch in wireless communication systems lead to increased data transmission demodulation errors due to inaccurate phase differences and circuit component mismatches, particularly between mixer and filtering circuits in I and Q channels.
Innovation Solution
A communication system with a baseband circuit, transmitting end circuit, and receiving end circuit, utilizing digital analog conversion, filtering, and amplification circuits, along with switches to bypass mixer and filtering components, allowing for the estimation and compensation of errors through calibration using compensation parameters to correct IQ mismatch.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If mixer and filtering circuits are used in I and Q channels for signal processing, then signal processing capability is improved, but circuit component mismatch occurs causing in-phase/quadrature-phase errors
Solution Approach 1:
The patent extracts the error estimation function from the main signal processing path by introducing dedicated test signals and separate estimation circuits. The baseband circuit sends test signals through the transmitting end filtering circuit and receiving end filtering circuit independently to measure and calculate mismatch parameters, separating the measurement function from the normal communication function.
Solution Approach 2:
The patent implements feedback by calculating compensation parameters based on the measured mismatch and feeding them back to correct the I/Q channel imbalance. The baseband circuit uses the test signal measurements to compute compensation values that are applied to subsequent signal processing, creating a closed-loop correction system.
2Manufacturing precision
If calibration is performed using test signals to estimate compensation parameters, then IQ mismatch is corrected, but additional calibration complexity is introduced
Solution Approach 1:
The baseband circuit performs multiple functions: it processes normal communication signals and also sends test signals for calibration purposes. The same transmitting end filtering circuit and receiving end filtering circuit are used for both normal operation and error estimation, eliminating the need for separate dedicated calibration hardware.
Solution Approach 2:
The system performs self-calibration by using its own internal test signals to measure its own mismatch characteristics. The baseband circuit generates test signals, sends them through the signal path, measures the resulting mismatch, calculates compensation parameters, and applies corrections without requiring external calibration equipment.
Data Source
AI summary
A communication system includes a baseband circuit, a transmitting end circuit, and a receiving end circuit is disclosed. The transmitting end circuit includes a digital analog conversion circuit and a transmitting end filtering circuit. The receiving end circuit includes a receiving end amplifying circuit, a receiving end filtering circuit, and an analog digital conversion circuit. A first data signal is transmitted to the analog digital conversion circuit through the digital analog conversion circuit and the transmitting end filtering circuit, so that the baseband circuit obtains a first compensation parameter. A second data signal is transmitted to the receiving end filtering circuit, the receiving end amplifying circuit and the analog digital conversion circuit through the digital analog conversion circuit and the transmitting end filtering circuit, so that the baseband circuit obtains a second compensation parameter. The baseband circuit performs calibration according to the first and the second compensation parameter.