滤波器设计和分析
您可以使用 DSP System Toolbox™ 函数与 App 设计和分析各种数字 FIR 及 IIR 滤波器。其中一些滤波器包括高级滤波器，如奈奎斯特滤波器、半带滤波器、高级等波纹滤波器和拟线性相位 IIR 滤波器。
设计方法根据设定计算滤波器系数。分析方法有助于验证所设计滤波器的设定。分析方法包括绘制滤波器的频率响应，找出滤波器的群延迟，或确定滤波器是否稳定。
滤波器设计和分析是互补和迭代的过程。在设计滤波器后，您可以借助分析工具确定滤波器是否符合要求的设定。该工具箱提供设计和分析 App，如 filterBuilder 和 filterAnalyzer。要了解如何使用 filterBuilder，请参阅Filter Builder Design Process。
您还可以使用 firlp2hp、iirlp2bs、iirlp2bpc 等函数将滤波器从一种形式变换为另一种形式。要了解有关频率变换的更多信息，请参阅Digital Frequency Transformations。
精选示例
Design Lowpass FIR Filters
Design lowpass FIR filters. You can extend many of the concepts presented here to other responses such as highpass, bandpass, and others.
FIR Halfband Filter Design
Design FIR halfband filters. Halfband filters are widely used in multirate signal processing applications when you interpolate or decimate by a factor of two. In many cases, you can implement halfband filters efficiently in a polyphase form because nearly half of the halfband filter coefficients are equal to zero.
Efficient Narrow Transition-Band FIR Filter Design
Design efficient FIR filters with very narrow transition-bands using multistage techniques. The techniques can be extended to the design of multirate filters. See Multistage Rate Conversion for an example of that.
Complex Bandpass Filter Design
Design complex bandpass filters. Complex bandpass filters are used in many applications from IF subsampling digital down converters to vestigial sideband modulation schemes for analog and digital television broadcast. One easy way to design a complex bandpass filter is to start with a lowpass prototype and apply a complex shift frequency transformation. This example reviews lowpass prototypes from single-stage single-rate FIR filters to multistage multirate FIR filters to IIR filters.
Design Fractional Delay FIR Filters
Design an implementation of fractional delay FIR filters.
Time Delay and Scaling in Multirate DSP Filters
Effect of time delay and scaling in multirate filters. Use
outputDelay function to calculate the time delay and
scaling.
