Ordinary Type Cascade Filter

Ordinary Type Cascade Filter is a cascade circuit that consists of multiple single-stage filters connected together. Each single-stage filter is a specific filter type, such as low-pass, high-pass, band-pass, band-stop, etc. In the cascade structure, the output of the previous single-stage filter will be used as the input of the next single-stage filter. In this way, when the input signal passes through the cascade structure, it is first filtered by the first filter, then filtered by the next filter, and so on. The final output signal contains only the desired frequency components after being filtered by multiple filters.

Specifically, assume that the cascade filter contains two single-stage filters, the first single-stage filter is a low-pass filter, and the second single-stage filter is a band-pass filter. When the input signal is sent to the cascade filter, it first passes through the low-pass filter to remove all frequency components above the cutoff frequency. Then, the output signal passes through the band-pass filter to remove the frequency components that are not within the band-pass range, and finally outputs the signal processed by the two filters. In this way, the cascade filter can achieve a more refined frequency screening effect, and realize tasks such as audio signal processing and filter design in wireless communications.