A device that converts a property of an input signal,such as frequency or phase,into an amplitude variation,depending on how the signal differs from a standard or reference signal.

• 鉴别器，鉴频器一种将输入信号的某一特征，如频率或相位转变为幅度变化装置，其变化大小因信号与标准或参考信号的不同程度而异