实验十-2FSK调制解调仿真实验课件

单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,2021/4/23,#,1,2FSK,调制解调仿真实验,一、实验目的,知识目标,理解,2FSK,调制与解调的,基本原理。,能力目标,能搭建,2FSK,系统仿真模型（包络检波法，相干解调法,）。,2,二进制频移键控（,2FSK,）是在一个码元持续时间,Ts,内用载波的两种不同的频率来表示传送数字“,1”,和“,0”,的。,2FSK,信号可看作是两个交错的,2ASK,信号之和，一个载频为,f,1,，另一个载频为,f,2,。,3,二,、实验原理,2FSK,调制原理框图,2FSK,信号有两种基本的解调方法：非相干解调（包络检波法）和相干解调（同步检测法）。,4,2FSK,包络检波法原理框图,5,2FSK,相干解调法,原理框图,1,、搭建仿真模型,（,1,）,2FSK,包络检波,仿真模型,图,6,三、实验内容,（,2,）,2FSK,相干解调,仿真模型,图,7,2FSK,包络检波,仿真模型,中各图符参数设置,如,下,：,8,图符编号,库,/,名称,参数,0,Source/PN Seq,Amp=1V,Offset=0,Rate=10Hz,Phase=0deg,No levels=2,1,，,2,，,9,，,10,Function/Half Rectify,Zero Point=0V,3,Operator/Logic/Not,Threshold=0,True Output=1,False Output=-1,14,Source/Sinusoid,Amp=1V,Freq=50Hz,Phase=0deg,15,Source/Sinusoid,Amp=1V,Freq=100Hz,Phase=0deg,7,Operator/Liner Sys Filters/Analog/Bandpass,Low,Cutoff=,30,Hz,Hi,Cutoff=,70,Hz,8,Operator/Liner Sys Filters/Analog/Bandpass,Low,Cutoff=,8,0Hz,Hi,Cutoff=1,2,0Hz,11,12,Operator/Liner Sys Filters/Analog/Lowpass,Low Cutoff=12Hz,13,Operator/Logic/Compare,Select Comparison=a=b,True Output=1,False Output=-1,2FSK,相干解调,仿真模型,中各图符参数设置,如,下,：,9,图符编号,库,/,名称,参数,0,Source/PN Seq,Amp=1V,Offset=0,Rate=10Hz,Phase=0deg,No levels=2,1,，,3,Function/Half Rectify,Zero Point=0V,2,Operator/Logic/Not,Threshold=0,True Output=1,False Output=-1,14,，,15,Source/Sinusoid,Amp=1V,Freq=50Hz,Phase=0deg,12,，,13,Source/Sinusoid,Amp=1V,Freq=100Hz,Phase=0deg,21,Operator/Liner Sys Filters/Analog/Bandpass,Low,Cutoff=,3,0Hz,Hi,Cutoff=,7,0Hz,22,Operator/Liner Sys Filters/Analog/Bandpass,Low,Cutoff=,8,0Hz,Hi,Cutoff=1,2,0Hz,9,10,Operator/Liner Sys Filters/Analog/Lowpass,Low Cutoff=12Hz,11,Operator/Logic/Compare,Select Comparison=a=b,True Output=1,False Output=-1,2,、仿真演示,系统时钟设置：,No of,Samples=512,Sample,Rate=500,Hz,运行系统，观察并分析,2FSK,两种解调方法仿真模型,图中各示波器的波形。可以,看出解调,出来的波形与输入的原基带信号基本保持一致，虽有一点延迟，但在允许范围内，仿真正确。,10,11,2FSK,包络检波各,点波形图,2FSK,相干解调各,点波形图,1,、,指出电路,模型中,，哪个图符的输出为,2FSK,已调信号？,2,、,2FSK,解调部分的比较器是否需要人为设置判决门限值？为什么？,12,四,、实验思考,