成形滤波可以在调制后对调制波以带通滤波方式完成，也可以在调制前对基带以低通滤波方式完成，两者的效果是相同的。在现代全数字调制解调器中，成形滤波器大都采用数字滤波器来实现。由于对基带信号进行数字滤波更为方便，因此成形滤波普遍采用基带数字滤波方案。-Shaping filter can be modulated by the modulation wave band-pass filtering is accomplished, it can before the modulation baseband low-pass filter manner, both results are the same. In the modern all-digital modem, the shaping filter most of the digital filters. Because of the digital baseband signal filtering more convenient, so forming a baseband filter commonly used digital filtering scheme.