定相 seeks to reproduce the 效果（效应） that arises when the 速度 of one of two 磁带 录音机 simultaneously playing back the same 信号 is altered When the 延迟 时间 of about 0 5 ms is slowly modulated the changing 相位 关系 i e the 移位/偏移 of one 波形 相对 to another between the two 信号 causes a 数 of 频率 频带 alternately to be cut and boosted

The result of 定相 is a 'whooshing' filter-like 效果（效应） 不 unlike that of a 数 of wah-wah pedals linked together each affecting a different part of the 频谱 In a 图表 显示 of the 频谱 the 效果（效应） appears as a 移位/偏移 梳状 each 'prong' corresponding to a 共鸣 峰 - hence the 技术 name 'comb filtering' applied to the 使用 of this 范围（排列） of 延迟 times 源 - Richard Dobson 1992 A 词典 of 电子 and 计算机 音乐 技术 牛津 University Press