final2ASK键控相干解调betaf.doc

用systemveiw仿真实现2ASK键控相干解调 01091008陈东01091009高万顺1.实验目的（1）. 了解数字频带传输系统的组成、工作原理及其抗噪声性能；（2）. 掌握通信系统的设计方法与参数选择原则；（3）. 掌握使用SystemView软件仿真通信系统的方法；2.实验内容（1）. 码元传输速率：20kBd；（2）. 设计一数字频带传输系统，并使用SystemView软件进行仿真；（3）. 获取各点时域波形，波形、坐标、标题等要清楚；滤波器的单位冲击相应和幅频特性曲线；（4）. 获取主要信号的功率谱密度；（5）. 获取不同信噪比下的眼图（至少5个）及星座图（星座图为选作内容）；（6）. 测试不加噪声条件下的误码率，获取误码率曲线为选作内容；（7）.数据分析及心得体会要求手写；（8）. 相干载波的提取为选作内容。3.实验原理2ASK信号的时间波形随二进制基带信号s(t)通断变化在，所以又称通断键控信号(OOK信号)。二进制振幅键控信号的产生方法有模拟相乘和数字键控。原理如图：2ASK信号与模拟调制中的AM信号类似。所以，对2ASK信号也能够采用非相干解调(包络检波法)和相干解调(同步检测法)，本实验应用相干解调，其原理方框图如下所示：4.系统组成、图符块参数设置及仿真结果系统组成图：编号库/名称参 数35Source: Sinusoid Amp = 0 v Freq = 0 Hz Phase = 0 deg Output 0 = Sine Output 1 = Cosine t38 34Source: SinusoidAmp = 1 vFreq = 40e+3 HzPhase = 0 degOutput 0 = SineOutput 1 = Cosine t3838Logic: SPDTSwitch Delay = 0 secThreshold = 0 vInput 0 = t35 Output 1Input 1 = t34 Output 1Control = t25 Output 025Source: PN SeqAmp = 500.e-3 vOffset = 500.e-3 vRate = 20e+3 HzLevels = 2Phase = 0 deg39Source: SinusoidAmp = 1 vFreq = 40e+3 HzPhase = 0 degOutput 0 = Sine Output 1 = Cosine t932Operator: GainGain =-1 dBGain Units = dB Power13Source: GaussNoiseStd Dev = 707e-3vMean = 0 v14Operator: Linear SysButterworth Bandpass IIR3 PolesLow Fc = 20e+3 HzHi Fc = 60e+3 HzQuant Bits = NoneInit Cndtn = TransientDSP Mode DisabledFPGA Aware = TrueRTDA Aware = Full31Operator: Linear SysBessel Lowpass IIR3 PolesFc = 20e+3 HzQuant Bits = NoneInit Cndtn = TransientDSP Mode DisabledFPGA Aware = TrueRTDA Aware = Full37Comm: CostasVCO Freq = 40e+3 HzVCO Phase = 0 degMod Gain = 1 Hz/vLoop Fltr = 1 + 1/s + 1/s2Output 0 = Baseband InPhaseOutput 1 = Baseband QuadratureOutput 2 = VCO InPhaseOutput 3 = VCO Quadrature t38Max Rate (Port 3) = 200e+3 Hz3Operator: SamplerInterpolating Rate = 20e+3 HzAperture = 0 secAperture Jitter = 0 sec4Operator: HoldLast ValueGain = 1Out Rate = 600e+3 Hz18Logic: BufferGate Delay = 0 secThreshold = 300.e-3 vTrue Output = 1 vFalse Output = 0 vRise Time = 0 secFall Time = 0 sec19Operator: DelayNon-Interpolating Delay = 50e-6 sec = 10.0 smp Output 0 = Delay t21 Output 1 = Delay - dT Max Rate (Port 0) = 600e+3 Hz 21Operator: ReSampleRate = 600e+3 Hz Max Rate = 600e+3 Hz22Comm: BER RateNo. Trials = 10e+3 bits Threshold = 500e-3 v Offset = 50e-6 sec Output 0 = BER Output 1 = Cumulative Avg t23 t24 Output 2 = Total Errors Max Rate (Port 1) = 2 Hz23Sink: Cndtnl StopAction = Go To Next Loop Memory = Retain all samples Threshold = 500e-3 Input from t22 Output Port 1 Max Input Rate = 2 Hz24Sink: Final ValueInput from t22 Output Port 1 Max Input Rate = 2 Hz调制信号为PN序列，正弦载波的频率为40k Hz。调制图：解调图：一、时域波形输入PN序列：输出序列：输入输出覆盖图：输入波形和输出波形瀑布图：输入和2ASK信号瀑布图：2ASK信号图:带通滤波器输出：提取的相干载波：通过低通滤波器：通过采样器：二、系统眼图无噪声眼图：此时眼图张开度较大，扫迹清晰信噪比50db：信噪比30db：信噪比20db：信噪比10db：信噪比0d