常用的数字滤波器有FIR数字滤波器和IIR数字滤波器｡ FIR数字滤波器具有精确的线性相位特性,在信号处理方面应用极为广泛,而且可以采用事先设计调试好的FIR数字滤波器IPCore来完成设计,例如Altera公司提供的针对Altera系列可编程器件的MegaCore,但是需要向Altera公司购买或申请试用版｡ 另外,对于相同的设计指标,FIR滤波器所要求的阶数比IIR滤波器高5~10倍,成本较高,而且信号的延迟也较大｡ IIR滤波器所要求的阶数不仅比FIR滤波器低,而且可以利用模拟滤波器的设计成果,设计工作量相对较小,采用FPGA实现的IIR滤波器同样具有多种优越性｡ -Commonly used digital filters have FIR digital filters and digital filter .FIR IIR digital filter has a precise linear phase characteristics, the signal processing is extensively used, and can be debugged using pre-designed FIR digital filter IPCore accomplished design, such as provided by Altera MegaCore Altera series for programmable devices, but need to purchase or apply for Altera trial version. in addition, for the same design specifications required by the order of the FIR filter IIR filters than high 5 ~ 10 times, high cost, and the order of the delayed signal is also larger .IIR filter required not only lower than the FIR filter, and can use the results of the analog filter design, design work is relatively small, using FPGA IIR filters also have a variety of advantages.