filter
A circuit that only allows signal components within a certain frequency range to pass normally and prevents other frequency components from passing is called a classical filter or filtering circuit. In fact, any electronic system has its own frequency band width (the limit of the highest frequency of a signal), and the frequency characteristic reflects this basic feature of an electronic system. Filter is an engineering application circuit designed according to the influence of circuit parameters on circuit bandwidth.
Modern filtration
The basic principle of using analog electronic circuit to filter analog signals is to use the frequency of the circuit.
wave filtering
This characteristic realizes the selection of frequency components in the signal. When filtering by frequency, the signal is regarded as an analog signal composed of sine waves with different frequencies, and the signal filtering is realized by selecting different frequency components.
wave filtering
1. When the high-frequency components in the signal are allowed to pass through the filter, this filter is called a high-pass filter.
2. When the low-frequency components in the signal are allowed to pass through the filter, this filter is called a low-pass filter.
3. Let the cutoff frequency of the low band be fp 1 and the cutoff frequency of the high band be fp2:
1) A filter whose frequency is between fp 1 and fp2 and can be attenuated by signals of other frequencies is called a bandpass filter.
2) On the contrary, the frequency attenuates in the range of fp 1 to fp2, and the filter that can pass through the outside is called a band-stop filter.