脉冲计数式鉴频器鉴频特性及其仿真研究

Frequency Discrimination Characteristics and Simulation of the Pulse Counting Type Frequency Discriminator

脉冲计数式鉴频器是适用于相对频偏较大的调频波的解调电路。它由带通滤波器、电压比较器和低通滤波器3部分组成。带通滤波器滤除调频信号中混杂的噪声信号,电压比较器电路将调频信号转换为调频脉冲序列,低通滤波器对调频脉冲序列进行滤波,得到调制信号。分析了脉冲计数式鉴频器的电路原理与组成;利用Multisim仿真软件,对脉冲计数式鉴频电路进行了构建和仿真。仿真结果表明,脉冲计数式鉴频器具有良好的线性特征,频带较宽,电路结构简单,适用于不同载波频率、频偏相对较大的调频信号的解调。

Pulse counting discriminator is a demodulation circuit suitable for frequency modulation wave with relative large frequency offset.It consists of three parts:bandpass filter,voltage comparator and low-pass filter.The bandpass filter filters out the mixed noise signal in the FM signal.The voltage comparator circuit converts the FM signal into the FM pulse train,and the low pass filter filters the frequency modulation pulse train to obtain the modulated signal.In this paper,the principle and composition of the circuit are analyzed,and the pulse counting frequency discrimination circuit is constructed and simulated by the Multisim simulation software.The simulation results show that the pulse counting discriminator has good linear characteristics,wide frequency band and simple circuit structure.It is suitable for demodulation of FM signals with different carrier frequencies and relativelarge frequency offset.