Adaptive low pass filter

Abstract

The invention provides an adaptive low pass filter, which mainly comprises a shaping circuit, a frequency voltage conversion circuit and a low pass filter circuit; signals to be detected are divided into two paths, one path of signals are input to the shaping circuit, the input signals are converted into pulse signals, the pulse signals are input to the frequency voltage conversion circuit, the input pulse signals are converted into voltage signals, the voltage signals are input to one end of an analog multiplier of the low pass filter circuit, and the cutoff frequency of the filter is indirectly adjusted through the voltage signals; and the other path of signals are directly input to the other end of the analog multiplier of the low pass filter circuit, so that automatic adaption from the cutoff frequency to the input frequency is realized. The adaptive low pass filter is realized by using the principle of frequency voltage conversion and simultaneously combining the analog multiplier, is simple in circuit structure, good in instantaneity, low in cost and convenient to adjust, and meets the requirement of large-range change of the frequency of the signals processed in different application fields.

Description

technical field [0001] The invention belongs to the technical field of filters, in particular to an adaptive low-pass filter. Background technique [0002] Filters are currently at the center of many design issues in radio technology and have a wide range of applications in areas such as data acquisition, signal processing, and communication systems. Among them, the low-pass filter is a necessary link in many signal processing processes. In the case of a narrow signal frequency range, a low-pass filter with a fixed cut-off frequency can be used for filtering. However, in many application fields, the frequency of the processed signal varies in a large range. At this time, it is difficult to meet the requirements with a low-pass filter with a fixed cut-off frequency, so it is necessary to design a low-pass filter with a variable cut-off frequency. [0003] At this stage, the existing technologies for realizing variable cut-off frequency are as follows: one is a low-pass filt...

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Problems solved by technology

[0004] The purpose of the present invention is to provide an adaptive low-pass filter with simple circuit structure, good real-time performance, low cost and convenient adjustment, so as to solve the problem that the low-pass filter with fixed cut-off frequency in the prior art is difficult to meet many applications. The frequency of the signal processed in the field changes in a large range and requires this technical problem

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