matlab濾波器外文翻譯外文文獻英文文獻iir數(shù)字濾波器的設計

1、IIR Digital Filter Design作者：Sanjit K.Mitra國籍：USA出處：Digital Signal Processing -A Computer-Based Approach 3eAn important step in the development of a digital filter is the determination of a realizable transfer function G

2、(z) approximating the given frequency response specifications. If an IIR filter is desired,it is also necessary to ensure that G(z) is stable. The process of deriving the transfer function G(z) is called digital filter d

3、esign. After G(z) has been obtained, the next step is to realize it in the form of a suitable filter structure. In chapter 8,we outlined a variety of basic structures for the realization of FIR and IIR transfer functions

4、. In this chapter,we consider the IIR digital filter design problem. The design of FIR digital filters is treated in chapter 10.First we review some of the issues associated with the filter design problem. A widely used

5、approach to IIR filter design based on the conversion of a prototype analog transfer function to a digital transfer function is discussed next. Typical design examples are included to illustrate this approach. We then co

6、nsider the transformation of one type of IIR filter transfer function into another type, which is achieved by replacing the complex variable z by a function of z. Four commonly used transformations are summarized. Finall

7、y we consider the computer-aided design of IIR digital filter. To this end, we restrict our discussion to the use of matlab in determining the transfer functions. 9.1 preliminary considerations There are two major iss

8、ues that need to be answered before one can develop the digital transfer function G(z). The first and foremost issue is the development of a reasonable filter frequency response specification from the requirements of the

9、 overall system in which the digital filter is to be employed. The second issue is to determine whether an FIR or IIR digital filter is to be designed. In the section ,we examine these two issues first . Next we review t

10、he basic analytical approach to the design of IIR digital filters and then magnitude approximates unity with an error of ,i.e., p ? ?. p pjp for e G ? ? ? ? ? ? ? ? ? ? , 1 ) ( 1In the stopband, defined by ,we require

11、that the magnitude approximates zero ? ? ? ? ? swith an error of .e., i s, ?for . , ) ( sj e G ? ? ? ? ? ? ? ? sThe frequencies and are , respectively, called the passband edge frequency and the p ? s ?stopband edge

12、frequency. The limits of the tolerances in the passband and stopband, p ?and , are usually called the peak ripple values. Note that the frequency response s ?of a digital filter is a periodic function of ,and the magn

13、itude response of a real- ) ( ? j e G ?coefficient digital filter is an even function of . As a result, the digital filter specifications ?are given only for the range . ? ? ? ? 0Digital filter specifications are ofte

14、n given in terms of the loss function,, in dB. Here the peak passband ripple and the minimum ) ( log 20 ) ( 10? ? ? j e G ? ? p ?stopband attenuation are given in dB,i.e., the loss specifications of a digital filter are

15、 s ?given by, dB p p ) 1 ( log 20 10 ? ? ? ? ?. dB s s ) ( log 20 10 ? ? ? ?9.1 Preliminary ConsiderationsAs in the case of an analog lowpass filter, the specifications for a digital lowpass filter may alternatively be

16、given in terms of its magnitude response, as in Figure 7.2. Here the maximum value of the magnitude in the passband is assumed to be unity, and the maximum passband deviation, denoted as 1/ ,is given by the minimum value