Method for eliminating mirror image interference in low-intermediate frequency receiver and relevant apparatus

Abstract

This invention provides a method for eliminating an amplitude mismatch and a phase mismatch in a pair of quadrature signals to eliminate image interference, in which, the said pair of quadrature signals includes an in-phase signal and a quadrature-phase signal. The said method includes compensating part of the in-phase signals into the quadrature-phase signals to make the compensated phase differ from the phase of in-phase signal by 90 deg. to eliminate phase difference of the pair and regulate the amplitude of the in-phase signal and the quadrature phase signal to a same value to eliminate its amplitude difference.

Description

technical field [0001] The present invention provides a novel image interference analysis and correction method, especially a method for eliminating the amplitude difference (Amplitude Mismatch) and phase difference (Phase Mismatch) in a pair of quadrature signals (Quadrature Signal), so as to eliminate Image interference in low-IF receivers. Background technique [0002] In the radio frequency transmission structure of the current wireless communication system, there are currently two types of receiver structures that can achieve high integration and multi-mode, one is a low intermediate frequency (Low IF) receiver, and the other is a direct conversion (Direct Conversion) receiver. ), or called zero intermediate frequency (Zero IF) receiver, both have advantages and disadvantages, and both have been widely valued and applied in the industry. The former can avoid the problems of DC offset and low-frequency noise, but it will be interfered by the image signal (Image Signal)....

AI Technical Summary

Problems solved by technology

[0005] In the common patent that mainly uses digital methods to correct the mismatch of a pair of quadrature signals to eliminate mirror images, Glas et al., in US Patent 6,330,290, "Digital I / Q imbalance compensation", proposed the use of test signals (Test Signal) and The compensation (Compensation) mechanism corrects the phase (Phase) and amplitude (Amplitude) of a pair of quadrature signals in a digitally controlled manner, and the correction method is to multiply a pair of quadrature signals by a complex preset value The purpose of image elimination is achieved by fine-tuning the phase and amplitude of the signal to be the same. However, under the structure of the above-mentioned common technologies, on the one hand, most of the mechanisms for image elimination are still based on complex analysis and algorithms. The correction of signal mismatch cannot be easily completed with a small number of components that can be easily combined with the receiver system. In order to deal with the problem of image cancellation, the mechanism of complex calculations and too many additional components will easily cause other problems such as energy consumption. The problem

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