Direct current imbalance suppression circuit for wireless receiver

Abstract

The present invention discloses a direct current imbalance suppression circuit for a wireless receiver. The direct current imbalance suppression circuit for the wireless receiver comprises a variable gain module, a peak detection circuit, a digital control module and an offset voltage generation module. The peak detection circuit is configured to detect the output of the variable gain module in the wireless receiver, the output of the variable gain module is taken as the input signals of a comparator, and the output comparator is taken as the input signals of the digital control module; and the digital control module is configured to control the offset voltage generation module to generate an offset voltage and is connected with the input end of the variable gain module; and the offset voltage generation module consists of current source array, switch pair array with mutually inverted control signals and a resister RC and generates the adaptive offset voltage adaptive through controlling the value of current flowing the RC. The direct current imbalance suppression circuit for a wireless receiver is able to rapidly perform direct current imbalance calibration, effectively inhibit the direct current imbalance of the wireless receiver, overcome the problem that the calibration of direct current imbalance is only performed at the condition of the direct current signal work in the prior art, and realize the direct current imbalance inhibition in the condition of the alternate current signal work.

Description

technical field [0001] The invention relates to a wireless receiver in a communication system, to a zero intermediate frequency receiver, and to a direct current offset suppression circuit used in a zero intermediate frequency receiver. Background technique [0002] In the communication system, the structures of wireless receivers mainly include superheterodyne, low-IF and zero-IF receivers. The superheterodyne structure has been used for many years. In addition to high cost and difficulty in integration, the superheterodyne has a trade-off problem between channel selection and image rejection. The low intermediate frequency structure adopts low intermediate frequency (about a few MHz), which avoids the DC offset problem of the zero intermediate frequency structure, but still has the problem of image rejection. The zero-IF structure directly down-converts the useful signal from the radio frequency to the baseband, avoiding the problem of image rejection, filtering and most ...

AI Technical Summary

Problems solved by technology

This method does not require large-area resistors and capacitors, and there is no problem with low-frequency cut-off frequencies, but this method can only calibrate the DC offset in static state

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