Abstract: Butterworth filter is the largest flat filter, with simple design and no obvious shortcomings in performance, so it has a wide range of applications. The advantage of Butterworth filter is that the frequency response curve in the passband is as flat as possible without fluctuation; The disadvantage is that when there is a long transition zone, it is easy to cause distortion in the transition zone. What is the specific Butterworth filter? What are the advantages and disadvantages of Butterworth filter? Let's take a look at this article! 1. What is a Butterworth filter?

Butterworth filter is a kind of electronic filters, which was first proposed by British engineer StephenButterworth in a paper published in the British magazine Radio Engineering in 1930. It is also called the maximum flat filter.

Butterworth filter is one of the most famous filters designed by modern design methods. Because of its simple design, no obvious shortcomings in performance, and because of its low Q value to the components that make up the filter, it is easy to make and achieve the design performance, so it has been widely used.

What are the advantages and disadvantages of Butterworth filter?

You already know what Butterworth filter is, so what are its advantages and disadvantages?

1, Butterworth filter Advantages:

The advantage of Butterworth filter is that the frequency response curve in the passband is as flat as possible without fluctuation, and gradually decreases to zero in the stopband. On the wave diagram of logarithmic amplitude diagonal frequency, starting from a certain boundary angular frequency, the amplitude gradually decreases with the increase of angular frequency and tends to negative infinity.

The attenuation rate of the first-order Butterworth filter is 6 dB per octave and 20 dB per decade. The attenuation rate of the second-order Butterworth filter is 12 dB per octave, and that of the third-order Butterworth filter is 18 dB per octave, and so on. The amplitude diagonal frequency of Butterworth filter decreases monotonously, and it is also the only filter that keeps the same shape regardless of the order and amplitude diagonal frequency curve. However, the higher the order of the filter, the faster the amplitude attenuation in the stopband. Other filters have different shapes of high-order amplitude diagonal frequency and low-order amplitude diagonal frequency.

2. Shortcomings of Butterworth filter

Butterworth filter is a kind of filter design classification, similar to Chebyshev filter. It has a variety of filters, such as Qualcomm, low-pass, bandpass and bandstop.

It has stable amplitude-frequency characteristics inside and outside the passband, but the transition band is long, which is easy to cause distortion. When calling Butterworth filter in MATLAB to simulate, the signal will always be slightly distorted in the first cycle.