实验二连续时间系统的频率响应37022613 张士龙一、实验目的1、加深对连续时间系统频率响应理解；2 、掌握借助计算机计算任意连续时间系统频率响应的方法。
二、实验原理连续时间系统的频率相应可以直接通过所得的表达式计算，也可以通过零极点图通过几何的方法来计算，而且通过零极点图可以迅速的判断系统的滤波特性。
1、在S平面上标出系统的另几点位置：2、选择S平面的坐标原点为起点，沿虚轴向上移动，计算此时各极点和零点与该点的模和夹角：3、与所有零点的模相乘，再除以各极点模，得到对应频率出的幅频特性值;4、将所有零点的幅角相加，减去各极点的幅角，得到对应频率处的相角。
三、实验内容1、流程图2、源程序#include <stdio.h>#include <math.h>main(){double rz[100], iz[100], rp[100], ip[100], m[50], n[50], h[50], mol1[100], mol2[100];double a[50],b[50],c[50],w[50],angle1[100],angle2[100];double g=1.0;int i,j,k;int z=0,p=0;float temp=0;printf("please input the zero point's number:");scanf("%d",&z);printf("please input the zero point's real part:");for(i=0;i<z;i++){scanf("%f",&temp);rz[i]=temp;}printf("please input the zero point's i part:");for(i=0;i<z;i++){scanf("%f",&temp);iz[i]=temp;}printf("please input the polar point's number:");scanf("%d",&p);printf("please input the polar point's real part:");for(i=0;i<p;i++){scanf("%f",&temp);rp[i]=temp;}printf("please input the polar point's i part:");for(i=0;i<p;i++){scanf("%f",&temp);ip[i]=temp;}w=0.0;for(i=1;i<=49;i++){w[i]=w[i-1]+0.1;}printf("the mol is:");for(i=0;i<50;i++){if(i%5==0)printf("\n");printf("z=%d,",z);g=1.0;for(k=0;k<z;k++){g*=sqrt(rz[k]*rz[k]+(w[i]-iz[k])*(w[i]-iz[k]));}m[i]=g;g=1;mol2[i]=1.0;for(k=0;k<p;k++){g=g*sqrt(rp[k]*rp[k]+(w[i]-ip[k])*(w[i]-ip[k]));}n[i]=g;if(p>=1){h[i]=(100*m[i])/(100*n[i]);printf("h[%d]=%f \n ,",i[i]);}}printf("the angle is:");for(i=0;i<50;i++){if(i%5==0)printf("\n");g=0;for(k=0;k<z;k++){angle1[k]=atan((iz[k]-w[i])/(rz[k]-0.000000001));if(rz[k]>0){if(w[i]>iz[k])angle1[k]=angle1[k]+3.1415936;elseangle1[k]=angle1[k]-3.1415936;}if(k>1)g=g+angle1[k];elseg=angle1[k];}a[i]=g;g=0;for(k=0;k<p;k++){angle2[k]=atan((ip[k]-w[i])/(rp[k]+0.));if(rp[k]>0){if(w[i]>ip[k])angle2[k]=angle2[k]+3.1415936;elseangle2[k]=angle2[k]-3.1415936;}if(k>1)g=g+angle2[k];elseg=angle2[k];b[i]=g;}b[i]=g;c[i]=(a[i]-b[i])*57.3;printf("%f\n",c[i]);}}3、实验结果系统一：幅频特性结果：0.0000.050 0.100 0.150 0.199 0.2480.2950.3400.3810.4170.4470.4710.4870.4960.5000.4980.4930.4840.4730.4600.4470.4340.4200.4070.3940.3810.3690.3570.3460.3350.3250.3160.3070.2980.2900.2820.2750.2670.2610.2540.2480.2420.2370.2310.2260.2210.2160.2120.2080.20345.00 41.99 38.66 34.99 30.97 26.5721.8016.7011.315.710.00-5.71-11.31-16.70-21.80-26.57-30.97-34.99-38.66-41.99-45.00-47.73-50.20-52.44-54.47-56.31-58.00-59.54-60.95-62.25-63.44-64.54-65.56-66.51-67.39-68.20-68.97-69.68-70.35-70.98-71.57-72.13-72.65-73.15-73.62-74.06-74.48-74.88-75.26-75.62分析计算可得：此系统为带通滤波器，相应的3dB带宽的起始频率和终止频率分别为0.7339和2.7177。
2、系统二：0.8240.8280.8380.8540.8690.8760.8670.8310.7700.6910.6080.5290.4590.4000.3500.3090.2750.2460.2220.2020.1840.1690.1560.1450.1350.1260.1180.1110.1040.0980.0930.0880.0840.0790.0750.0720.0690.0650.0620.0600.0570.0550.0520.0500.0480.0460.0440.0430.0410.040 197.61188.75179.05168.29156.23142.78128.05112.5597.1182.5269.3157.6047.2838.1429.9522.5415.759.463.58-1.96-7.21-12.21-16.98-21.56-25.95-30.17-34.23-38.14-41.90-45.52-49.01-52.37-55.61-58.72-61.72-64.60-67.37-70.04-72.60-75.07-77.45-79.73分析算可得：此系统为低通滤波器，相应的3dB带宽的终止频率为1。