Analog band pass filter

Abstract

The embodiment of the invention discloses an analog band pass filter which is used for improving the out-of-band rejection capacity under the condition of keeping the volume of the filter constant. The analog band pass filter provided by the embodiment of the invention comprises a first inductor, a second inductor, a first capacitor, a second capacitor, a third inductor and a third capacitor, wherein the second inductor and the second capacitor form a series circuit; the third inductor and the third capacitor form a parallel circuit; the series circuit is connected with the parallel circuit; the component value of the series circuit and the parallel circuit is the same as that of a Butterworth filter circuit; the first inductor and the first capacitor are respectively connected on the series circuit in parallel; the first inductor and the first capacitor are connected with the parallel circuit; the first inductor and the first capacitor form a coupling channel between the connected two ends; and crossed coupling is provided between the two ends connecting the first inductor and the first capacitor.

Description

technical field [0001] The invention relates to the technical field of filter circuits, in particular to an analog bandpass filter. Background technique [0002] Filters are an essential component in modern communication systems. With the rapid development of modern communication technology, the available spectrum resources are becoming more and more tense. Therefore, the requirements for the frequency selection characteristics of filters are also getting higher and higher. For example, in order to improve communication quality and avoid interference between adjacent channels, the filter must have good out-of-band suppression; in order to improve system sensitivity, it is required to have a lower insertion loss in the passband; and in order to reduce the signal distortion, and requires flat amplitude-frequency characteristics and group delay characteristics in the passband; and in order to meet the current trend of miniaturization of communication equipment, the filter is r...

AI Technical Summary

Problems solved by technology

[0004] Among them, the Butterworth filter has a monotonic attenuation curve, the flattest in the passband, but the worst out-of-band rejection. If you want to achieve a steep transitional attenuation change between the passband and the stopband, you must reach a sufficiently high order If the number is high, a large number of capacitors and inductors are required. The more devices are needed, the more complex the circuit structure will be, and the corresponding filter size will also increase, which is contrary to the miniaturization requirements of the filter.

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