R语言 signal包 buttord()函数中文帮助文档(中英文对照)

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buttord(signal)
buttord()所属R语言包：signal

                                         Butterworth filter order and cutoff
                                         巴特沃斯滤波器阶数和截止

                                         译者：生物统计家园网 机器人LoveR

描述----------Description----------

Compute butterworth filter order and cutoff for the desired response
计算巴特沃斯滤波器阶数和截止所需的响应


用法----------Usage----------


buttord(Wp, Ws, Rp, Rs)



参数----------Arguments----------

参数：Wp, Ws
pass-band and stop-band edges. For a low-pass or high-pass filter, Wp and Ws are scalars. For a band-pass or band-rejection filter, both are vectors of length 2. For a low-pass filter, Wp < Ws. For a high-pass filter, Ws > Wp. For a band-pass (Ws[1] < Wp[1] < Wp[2] <     Ws[2]) or band-reject (Wp[1] < Ws[1] < Ws[2] < Wp[2]) filter design, Wp gives the edges of the pass band, and Ws gives the edges of the stop band. Frequencies are normalized to [0,1], corresponding to the range [0, Fs/2].  
通带和阻带的边缘。低通或高通滤波器，Wp和Ws是标量。对于一个带通或带阻滤波器中，两个向量的长度为2。对于一个低通滤波器，Wp < Ws。对于一个高通滤波器，Ws > Wp。对于带通（Ws[1] < Wp[1] < Wp[2] <     Ws[2]）或带阻（Wp[1] < Ws[1] < Ws[2] < Wp[2]）滤波器的设计，Wp给出的通带的边缘，和Ws给出的边缘阻带。频率被归一化到[0,1]，对应的取值范围为[0，Fs / 2的]。


参数：Rp
allowable decibels of ripple in the pass band.  
允许分贝的通带中的纹波。


参数：Rs
minimum attenuation in the stop band in dB.  
以dB为单位的阻带中的最小衰减。


Details

详细信息----------Details----------

Deriving the order and cutoff is based on:
派生的顺序和截止的基础上：

With some algebra, you can solve simultaneously for Wc and n given Ws, Rs and Wp, Rp. For high-pass filters, subtracting the band edges from Fs/2, performing the test, and swapping the resulting Wc back works beautifully. For bandpass- and bandstop-filters, this process significantly overdesigns. Artificially dividing n by 2 in this case helps a lot, but it still overdesigns.
对于某些代数，你可以同时解决Wc和n给定的Ws，Rs和Wp，Rp。对于高通滤波器，减去从fs / 2的频带边缘，进行测试，并交换Wc回精美的作品。对于带通和带阻滤波器，此过程中显着overdesigns。人为地划分：n在这种情况下，有很大帮助，但它仍然overdesigns的。


值----------Value----------

An object of class FilterOfOrder with the following list elements:
对象的类FilterOfOrder下面的列表元素：


参数：n
filter order  
滤波器的阶数


参数：Wc
cutoff frequency  
截止频率


参数：type
filter type, one of &ldquo;low&rdquo;, &ldquo;high&rdquo;, &ldquo;stop&rdquo;, or &ldquo;pass&rdquo;  
过滤器类型，一个“低”，“高”，“停止”，或“通行证”

This object can be passed directly to butter to compute filter coefficients.
这个对象可以被直接传递给butter计算滤波器系数。


（作者）----------Author(s)----------


Original Octave version by Paul Kienzle,
<a href="mailto:pkienzle@user.sf.net">pkienzle@user.sf.net</a>. Conversion to R by Tom Short.



参考文献----------References----------



参见----------See Also----------

butter, FilterOfOrder, cheb1ord
butter，FilterOfOrder，cheb1ord


实例----------Examples----------


Fs <- 10000
btord <- buttord(1000/(Fs/2), 1200/(Fs/2), 0.5, 29)
plot(c(0, 1000, 1000, 0, 0), c(0, 0, -0.5, -0.5, 0),
     type = "l", xlab = "Frequency (Hz)", ylab = "Attenuation (dB)")
bt <- butter(btord)
plot(c(0, 1000, 1000, 0, 0), c(0, 0, -0.5, -0.5, 0),
     type = "l", xlab = "Frequency (Hz)", ylab = "Attenuation (dB)",
     col = "red", ylim = c(-10,0), xlim = c(0,2000))
hf <- freqz(bt, Fs = Fs)
lines(hf$f, 20*log10(abs(hf$h)))


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注：
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