外文翻譯_外文文獻(xiàn)_英文文獻(xiàn)_iir數(shù)字濾波器的設(shè)計(jì)(已改無錯(cuò)字)
2022-09-03 19:55:03 本頁面
【正文】 ital Filter Design In the case of IIR filter design, the most mon practice is to convert the digital filter specifications into analog lowpass prototype filter specifications, and then to transform it into the desired digital filter transfer function G(z). This approach has been widely used for many reasons:(a) Analog approximation techniques are highly advanced.(b) They usually yield closedform solutions.(c) Extensive tables are available for analog filter design.(d) Many applications require the digital simulation of analog filters.In the sequel, we denote an analog transfer function as ,Where the subscript a specifically indicates the analog domain. The digital transfer function derived form Ha(s) is denoted by The basic idea behind the conversion of an analog prototype transfer function Ha(s) into a digital IIR transfer function G(z) is to apply a mapping from the sdomain to the zdomain so that the essential properties of the analog frequency response are preserved. The implies that the mapping function should be such that (a) The imaginary(j) axis in the splane be mapped onto the circle of the zplane.(b) A stable analog transfer function be transformed into a stable digital transfer function.To this end,the most widely used transformation is the bilinear transformation described in Section . Unlike IIR digital filter design,the FIR filter design does not have any connection with the design of analog filters. The design of FIR filter design does not have any connection with the design of analog filters. The design of FIR filters is therefore based on a direct approximation of the specified magnitude response,with the often added requirement that the phase response be linear. As pointed out in Eq.(), a causal FIR transfer function H(z) of length N+1 is a polynomial in z1 of degree N. The corresponding frequency response is given by .It has been shown in Section that any finite duration sequence x[n] of length N+1 is pletely characterized by N+1 samples of its discretetime Fourier transfer X(). As a result, the design of an FIR filter of length N+1 may be acplished by finding either the impulse response sequence {h[n]} or N+1 samples of its frequency response . Also, to ensure a linearphase design, the condition of Eq.() must be satisfied. Two direct approaches to the design of FIR filters are the windowed Fourier series approach and the frequency sampling approach. We describe the former approach in Section . The second approach is treated in Problem . In Section we outline puterbased digital filter design methods. 作者：Sanjit 國籍：USA出處：Digital Signal Processing A ComputerBased Approach 3eIIR數(shù)字濾波器的設(shè)計(jì)在一個(gè)數(shù)字濾波器發(fā)展的重要步驟是可實(shí)現(xiàn)的傳遞函數(shù)G（z）的接近給定的頻率響應(yīng)規(guī)格。如果一個(gè)IIR濾波器是理想，它也有必要確保了G（z）是穩(wěn)定的。該推算傳遞函數(shù)G（z）的過程稱為數(shù)
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