Switch capacitor band-pass filter and continuous time band-pass filter

Abstract

The present invention relates to a switch capacitance second order band-pass filter which is provided with four programmable capacitors, if two integrating capacitor values of the filter are C1 and C2 respectively, capacitance values of four programmable capacitor are Alpha1C1, Alpha2C2, Alpha3C1, Alpha4C2, wherein, Alpha1-Alpha4 satisfies: Alpha1=Alpha2=Omega0T, Alpha3=1 / Q, Alpha4=KT. Wherein, Omega0 is filter center frequency, Q as filter figure of merit, and K as filter gain coefficient. Thereby the three parameters can be adjusted independently. The present invention also puts forward continuous time RC structure with above band-pass filter and difference structure.

Description

technical field [0001] The invention relates to a filter circuit, in particular to a switched capacitor band-pass filter and a continuous time band-pass filter. Background technique [0002] Bandpass filter is a very widely used analog circuit. Cascading basic second-order bandpass filters is a common way to construct higher-order bandpass filters. In this cascade mode, finding a suitable second-order band-pass filter structure becomes the key to technology. [0003] In the application of filters, for various needs, it is often necessary to programmatically control the filtering characteristics of the filter. Sometimes it is to correct the deviation of frequency, Q value and gain characteristics due to process deviation or design mismatch (Mismatch), and sometimes it is because the filter itself needs to have controllable frequency characteristics (mainly refers to the passband frequency, in-band ripple, and gain). [0004] At this time, the value of some resistors or ca...

AI Technical Summary

Problems solved by technology

But due to α 3 = K ω 0 , Adjust alpha 2 、α 5 to adjust ω 0 At the same time, K is also adjusted, that is, ω 0 There is a joint relationship with K, and ω cannot be realized 0 independent adjustment of

Images