Delay calculation by cross-correlation method

bqgup

Delay calculation by cross-correlation method [Copy link]

 

# Calculate time delay using the cross-correlation method#### Assume that the known signal is a Chirp signal with a starting frequency of 250Hz and an ending frequency of 2000Hz, and the received signal is a Chirp signal with a certain attenuation in amplitude that is collected by the microphone using the ADC. # Cross-correlation method for time delay``` %%% Cross-correlation method for time delay%%% N=2048; % Length Fs=10000; % Sampling frequency n=0:N-1; t=n/Fs; % Time series%% Chirp signal x = chirp(t,250,0.2047,2000); x = [x,zeros(1,2*N)]; % To ensure that the delay is within twice the signal length, otherwise adjust 2*N by 2 %% Received Chirp signal ADC1 = 0.78 * chirp(t,250,0.2047,2000); % Assume that the received information has amplitude attenuation tao = 0.15; % Delay Ndelay = fix(tao*Fs); % Convert to delay points ADC1 = [zeros(1,Ndelay),ADC1,zeros(1,length(x)-Ndelay-length(ADC1))];%,zeros(1,2048)]; %% Cross-correlation function [c,lags]=xcorr(x,ADC1); % Cross-correlation subplot(211); xaxis = 1:1:length(x); plot(xaxis,x,'r'); hold on; plot(xaxis,ADC1,':'); legend('x signal', 'ADC1 signal'); xlabel('Time/s');ylabel('x(t) ADC1(t)'); title('Original signal');grid on; hold off subplot(212); plot(lags/Fs,c,'r'); title('Correlation function'); xlabel('Time(s)');ylabel('Rxadc1'); grid on [Am,Lm]=max(c); d = Lm - (length(c)+1)/2; phy=(2*10*d*180/Fs); phy = rem(phy,360)% remainder 360 phy = -180 Delay=d/Fs Delay = -0.1500 ``` #### The running result is correct, the graph is as follows: <ignore_js_op> <img style="cursor:pointer;" id="aimg_466660" aid="466660" src="static/image/common/none.gif" onclick="zoom(this, this.getAttribute('zoomfile'), 0, 0, '0')" zoomfile="data/attachment/forum/202003/26/112256sgmn80g09hi9e6ze.png" file="data/attachment/forum/202003/26/112256sgmn80g09hi9e6ze.png" inpost="1" onmouseover="showMenu({'ctrlid':this.id,'pos':'12'})" /> <div class="tip tip_4 aimg_tip" id="aimg_466660_menu" style="position: absolute; display: none" disautofocus="true"> <div class="xs0"> <p><strong>1.png</strong> <em class="xg1">(12.15 KB, downloads: 0)</em></p> <p> <a href="javascript:;" class="loginf" >download attach</a> <a href="javascript:;" onclick="showWindow(this.id, this.getAttribute('url'), 'get', 0);" id="savephoto_466660" url="home.php?mod=spacecp&ac=album&op=saveforumphoto&aid=466660&handlekey=savephoto_466660">save to album</a> </p> <p class="xg1 y">2020-3-26 11:22 上传</p> </div> <div class="tip_horn"></div> </div> </ignore_js_op>

littleshrimp

Thanks for sharing. Are you playing with sound source localization?

bqgup

littleshrimp posted on 2020-3-26 11:52 Thanks for sharing. Are you playing with sound source localization?

Yes, I think this is very interesting. I hope the experts can give me some advice.

littleshrimp

bqgup posted on 2020-3-26 18:17 Yes, I think this is quite interesting. I hope the masters can give me some advice

I have already studied this step and should learn from you.

Smile丶

Sir, what does the final calculation result of phy mean?

bqgup

Smile丶Posted on 2020-5-18 14:10 Boss, what does the final phy calculation result mean?

Phase Difference