Gain enhancement type N-channel active band-pass filter adopting differential clock

Abstract

The invention discloses a gain enhancement type N-channel active band-pass filter adopting a differential clock. The gain enhancement type N-channel active band-pass filter comprises an N frequency-division ring counter, a differential clock circuit and an operational transconductance amplifier, wherein the N frequency-division ring counter is formed by annularly connecting N D triggers; a sampling pulse sequence is output from the Q end of each D trigger; the differential clock circuit comprises N switch branches and N / 2 capacitors, and every two switch branches and one capacitor constitute an H-shaped circuit structure; switches in the upper left position and the lower right position of each H-shaped circuit structure are simultaneously connected with the Q end of one D trigger of the N frequency-division ring counter, and switches in the lower left position and the upper right position of each H-shaped circuit structure are simultaneously connected with the Q end of another D trigger of the N frequency-division ring counter; two ends of the operational transconductance amplifier are connected to two ends of the differential clock circuit respectively. The gain enhancement type N-channel active band-pass filter has the characteristics of large adjustable range of center frequency and large gain.

Description

technical field [0001] The invention relates to an analog filter, in particular to an N-channel active band-pass filter with improved differential clock gain. Background technique [0002] In the wireless communication system, the bandpass filter applied in the wireless receiver needs to have good selectivity, wide dynamic range and freely adjustable center frequency. The growing number of multimode and multifrequency wireless devices has driven the development of bandpass filters with good selectivity and wide tunable center frequencies. Active RC filters, whose characteristic parameters are related to the RC time constant, but the precision of integrated resistors and integrated capacitors is very poor, and accurate time constants are difficult to obtain. The transconductance capacitor filter has the advantages of simple circuit, programmable control and easy integration, but it needs to make a trade-off between power consumption, quality factor and center frequency. In ...

AI Technical Summary

Problems solved by technology

[0004] The technical problem to be solved by the present invention is that the present N-channel active bandpass filter has small gain, narrow free adjustable range of center frequency, large chip size and complex circuit, etc., and provides a differential clock gain-enhancing type N-channel active bandpass filter

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