Digital IIR filters find wide applications in fields such as speech processing, image processing and noise/echo cancellation. In recent years, the design of linear phase IIR filter becomes a very hot issue of research interest. As we know, FIR filters designed to approximate a magnitude response that has a narrow transition band between the passband and the stopband usually require a large number of multipliers and they have a large delay also. Hence we prefer to IIR digital filters that have less number of multipliers than their corresponding FIR counterparts but one of disadvantages is that an IIR filter cannot reach an exactly linear phase. The importance of the phase response linearity of a digital filter was recognized in early yearsu27 research and Finite Impulse Response (FIR) filters provided a perfect solution to this requirement. However, due to fundamental incompetence of FIR filters stated before, approximately linear phase IIR filters became the focus of research as a compromise between the implementation cost and the linearity of the phase response. About twenty years ago, most of researches on digital filters and signal processing, when and if they discussed the design of digital filter, they treated mainly the approximation of the magnitude response, or else, dealt with magnitude and phase responses separately. For example, as we know, the one of the most well known methods for solving the problem of IIR filter phase linearity was based on the application of cascading the prototype IIR filter with an allpass phase equalizer. In recent years, new methods have been proposed for the simultaneous approximation of both the magnitude and group delay of IIR digital filter. They have less number of multipliers than their corresponding FIR counterparts and yet provide the required phase response. This topic is covered all through this thesis.Dept. of Electrical and Computer Engineering. Paper copy at Leddy Library: Theses u26 Major Papers - Basement, West Bldg. / Call Number: Thesis2003 .D35. Source: Masters Abstracts International, Volume: 42-02, page: 0643. Adviser: H. K. Kwan. Thesis (M.A.Sc.)--University of Windsor (Canada), 2003.
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机译：数字IIR滤波器在语音处理，图像处理和噪声/回声消除等领域得到了广泛的应用。近年来，线性相位IIR滤波器的设计成为研究兴趣中非常热门的问题。众所周知，FIR滤波器被设计为近似幅度响应，该幅度响应在通带和阻带之间具有狭窄的过渡带，通常需要大量的乘法器，并且它们的延迟也很大。因此，我们希望IIR数字滤波器的乘法器数量少于其对应的FIR滤波器，但缺点之一是IIR滤波器无法达到精确的线性相位。早期的研究已经认识到数字滤波器的相位响应线性度的重要性，而有限冲激响应（FIR）滤波器为这一要求提供了理想的解决方案。但是，由于前面所述的FIR滤波器的基本功能不足，近似线性相位IIR滤波器成为实现成本和相位响应线性之间的折衷，成为了研究的重点。大约二十年前，关于数字滤波器和信号处理的大多数研究在讨论数字滤波器的设计时，如果主要讨论幅度响应的近似值，或者分别处理幅度响应和相位响应。例如，众所周知，解决IIR滤波器相位线性问题的最著名方法之一是基于将原型IIR滤波器与全通相位均衡器级联的应用。近年来，已经提出了用于同时近似IIR数字滤波器的幅度和群时延的新方法。它们的倍频器数量少于其对应的FIR倍数，但仍提供所需的相位响应。本论文涵盖了该主题。电气和计算机工程系。莱迪图书馆的纸质副本：论文主要论文-西楼地下室。 /电话号码：Thesis2003 .D35。资料来源：Masters Abstracts International，第42卷，第0643页。顾问：关国光（H. K. Kwan）。论文（硕士）-温莎大学（加拿大），2003。
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