中国海洋大学声学基础实验报告

75khz,N=10,D=55cm,接受信号与发射信号的相关604020magnitude0-20-4000.0050.010.0150.02t/s0.0250.030.035

两接收声纳的灵敏度0.050.0450.040.0350.030.0250.020.0150.01 3ch2ch3 ue/v3.544.555.510khz66.577.58

function sens=sensitiveness(f,fs,N,d,data,timedelay,channel) %f 脉冲信号频率 %fs 采样率 %N 脉冲个数

úta 发射和接收数据 %timedelay 时间延时点数 %channel 通道 c=1500;%声速

Tr=d/100*1.2/c*fs;%到达时间大约点数 Ts=floor(N/f*fs);%脉冲点数 T=floor(Tr+Ts);

y=data(timedelay:timedelay+T,channel);%收到的直达波信号 x=data(timedelay:timedelay+Ts,2);%发射信号 x1=x/max(x);%归一化 y1=y/max(y);

yy=xcorr(y1,x1);

num=find(yy==max(yy))-length(y1');%找到精确的接收时间点

sens=sqrt(trapz((data(timedelay+num:timedelay+num+Ts-1,channel)).^2)/Ts);%计算直达波信号的有效值 T1=0.357ms;d=53.55cm

T2=0.761ms;d=114.2cm 池面反射距离107cm，壁面反射距离96cm。

clc;close all;clear all; load alldata;

data=zeros(32,110*2000); for num=1:32

x=alldata(:,num,:);

temp=reshape(x,110,2000);

data(num,:)=reshape(temp',1,110*2000); end

c=1500; fs=6000;

td=0.5*fs;%需要的点数

loc=[0.0,0.0;0.99,-0.11;1.98,-0.21;2.97,-0.32;3.96,-0.43;4.59,-0.53;5.59,-0.64;6.39,-0.75;7.94,-0.84;8.95,-0.90;9.94,-0.95;10.94,-1.01;11.94,-1.07;12.93,-1.13;13.93,-1.19;14.93,1.25;15.93,-1.29;16.94,-1.29;17.93,-1.29;18.93,-1.29;19.93,-1.29;20.92,-1.29;21.92,-1.29;22.92,-1.29;23.92,-1.29;24.92,-1.29;25.92,-1.29;26.92,-1.29;27.92,-1.29;28.92,-1.29;29.92,-1.29;30.90,-1.29];

signd=zeros(361,td);%时延加和信号 theta=-pi:pi/180:pi; for count=1:361

timdelay=round(loc*[cos(theta(count));sin(theta(count))]/c*fs); for cell=1:32

signd(count,:)=signd(count,:)+data(cell,110001+timdelay(cell):110000+td+timdelay(cell)); end end

target=sum((signd.^2)');

plot(theta*180/pi,target/max(target),'b');

%宽带频域波数形成0-180度上布放声纳

%----------------------parameters of array------------------------ clc;

clear all; close all;

c=1500;%海水声速

loc=[0.0,0.0;0.99,-0.11;1.98,-0.21;2.97,-0.32;3.96,-0.43;4.59,-0.53;5.59,-0.64;6.39,-0.75;7.94,-0.84;8.95,-0.90;9.94,-0.95;10.94,-1.01;11.94,-1.07;12.93,-1.13;13.93,-1.19;14.93,1.25;15.93,-1.29;16.94,-1.29;17.93,-1.29;18.93,-1.29;19.93,-1.29;20.92,-1.29;21.92,-1.29;22.92,-1.29;23.92,-1.29;24.92,-1.29;25.92,-1.29;26.92,-1.29

;27.92,-1.29;28.92,-1.29;29.92,-1.29;30.90,-1.29]; N=32;

%------------------------Datas received-------------------------- load alldata;

data=zeros(32,110*2000); for num=1:32

x=alldata(:,num,:);

temp=reshape(x,110,2000);

data(num,:)=reshape(temp',1,110*2000); end

fs=6000;

%-----------------------------DFT-Beamforming--------------------------------- for cell=1:N

yf(cell,:)=fft(data(cell,:)); end

f1=500;f2=600;

fn1=round(f1*length(yf(1,:))/fs);fn2=round(f2*length(yf(1,:))/fs);%频率对应的序号

fband=linspace(f1,f2,fn2-fn1+1); beta=0:pi/180:pi;

for betan=1:length(beta)

timdelay=round(loc*[cos(beta(betan));sin(beta(betan))]/c*fs); for fn=1:fn2-fn1+1%频率计数 for cell=1:N%阵元计数

y(cell,fn)=yf(cell,fn1+fn-1)*exp(-1j*2*pi*fband(fn)*timdelay(cell)); end end

summ=abs(sum(y));

di(betan)=sum(summ.^2); end

plot(beta,di/max(di));

xlabel('angle');title('CFB,500-600hz');

clc;close all;clear all; load alldata;

data=zeros(32,110*2000); for num=1:32

x=alldata(:,num,:);

temp=reshape(x,110,2000);

data(num,:)=reshape(temp',1,110*2000); end