How to choose the correct passband frequency and stopband frequency of a low pass Equiriple Fir filter?

Question

afef 2017-3-29

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/332513-how-to-choose-the-correct-passband-frequency-and-stopband-frequency-of-a-low-pass-equiriple-fir-fil

评论： Star Strider 2017-3-29

I design a low pass Equiriple Fir filter with 3 dB of ripple in the pass-band from 0 to 64 Hz and at least 60 dB of attenuation in the stop-band. I want to know the correct passband frequency and stopband frequency I choose here the passband frequency 0.45π and stopband frequency 0.5π

and with this the passband frequency 0.45π and stopband frequency 0.49π

and here the passband frequency 0.49π and stopband frequency 0.5π

Can anyone help me to choose the right one?

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Star Strider 2017-3-29

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/332513-how-to-choose-the-correct-passband-frequency-and-stopband-frequency-of-a-low-pass-equiriple-fir-fil#answer_260857

The ‘right’ filter is the design that does what you want it to do considering your data.

With FIR filters, the filter length increases significantly with shorter transition regions (steeper rolloffs). For example, if you have a short data vector, the third design (passband frequency 0.49π and stopband frequency 0.5π) may be too long to work with your data.

Shorter filters are more efficient, so if the filters you posted all give the same essential performance (as I expect they would), I would use the first design, with the passband frequency 0.45π and stopband frequency 0.5π.