Chebyshev filter is a band-pass filter, which has some advantages of high-pass filter and low-pass filter. It has the characteristics of high stopband edge and low ripple, and its bandwidth is fixed. Its advantages are high passband gain and low stopband gain, so it meets the requirements of Qualcomm and low-pass filters and has good suppression ability.

The design method of Chebyshev filter is usually based on linear least squares. The basic idea of this method is to select a set of coefficients to minimize the system error under given constraints.

Chebyshev filter is widely used and plays an important role in signal processing, communication, control and other fields. For example, Chebyshev filter can be used for Gaussian noise filtering, phase and amplitude filtering and other applications.

In the linear least mean square design method, the design process of Chebyshev filter can be divided into two parts:

1. Through special linear transformation, the given constraint is transformed into a relatively simple form;

2. Under the constraint of linear transformation, the system coefficients are calculated by least square method or least square method.

The ripple of Chebyshev filter mainly comes from its passband edge frequency, while the stopband gain mainly comes from its stopband cut-off frequency. According to different application requirements, we can adopt different design methods to meet these limitations.