Frequency self-tuning circuit used for Gm-C filter

Abstract

The invention belongs to the technical field of integrated circuit designs, and particularly discloses a frequency self-tuning circuit of a trans-conductance capacitor (Gm-C). For the frequency self-tuning circuit, trans-conductance and capacitor arrays in a filter are separately taken out to form an integrator on the basis of an automatic amplitude-locking principle; by comparing the output of the integrator with the amplitude of a reference signal, a digital control bit is generated; the counting of a counter is controlled, and the capacitor arrays of the integrator and the filter are adjusted according to an output code word of the counter to ensure that the unit gain bandwidth of the integrator is the same as a reference frequency; and simultaneously, the cut-off frequency of the filter is tuned to be the same as the reference frequency. The method is simple and stable, has a wider tuning range compared with the prior method, has very low tuning power consumption by using a digital module, cannot influence the performance of the filter, and has very strong practical values.

Description

technical field [0001] The present invention relates to a kind of filter frequency self-tuning method, and this method can be used in transconductance capacitance (G m -C) In the filter of the structure, the cutoff frequency of the filter is corrected. Background technique [0002] The analog filter is a very important module of the analog baseband processing part of the radio frequency wireless communication chip. The filtering characteristics of the filter and the accuracy of the cut-off frequency determine the receiver's suppression of out-of-band interference and the bit error of the entire communication system. Bit rate plays a decisive role. The cutoff frequency of the filter is extremely sensitive to the process angle, and there will be a deviation of about 30% at each process angle. Therefore, the frequency tuning module is an important part of the filter. Contents of the invention [0003] The object of the present invention is to provide a kind of for transcond...

AI Technical Summary

Problems solved by technology

[0003] The object of the present invention is to provide a kind of for transconductance capacitance (G m -C) The frequency self-tuning circuit of the filter, to improve the tuning method of the traditional transconductance capacitor filter, solve the problem of the limited tuning range of the traditional tuning method, and reduce the power consumption of the tuning module

Images