generate audio signals -凯发k8网页登录

load audio signal

load an audio file containing a sample of handel's "hallelujah chorus."

load handel;

plot audio signal

plot the data to identify five distinct segments. each segment represents a "hallelujah" in the chorus. the segments are annotated as 1 to 5.

ly = length(y);
lspan = 1:ly;
t = lspan/fs;
hf = figure;
plot(t,y./max(y))
axis tight;
title("signal (handel''s hallelujah chorus) vs time");
xlabel("time (s)");
ylabel("amplitude");
markers = struct('xpos',[0.2,0.4,0.55,0.65,0.8],'string',num2str([1:5]'));
for i = 1:5,
    annotation(hf,'textbox',[markers.xpos(i) 0.48 0.048 0.080],'string', markers.string(i),'backgroundcolor','w','fontsize',16);
end

create a dataacquisition and add audio output channels

this example uses a 5.1 channel sound system with device id 'audio2'.

1. create a dataacquisition with directsound as the vendor and add an audio output channel to it.

dd = daq("directsound");
nch = 6;
addoutput(dd, "audio2", 1:nch, "audio");

2. update the generation scan rate to match the audio sampling rate.

dd.rate = fs;

3. generate audio signals (handel's "hallelujah chorus"). "hallelujah" should be voiced five times, one for each segment depicted in the figure on all channels of the speaker system.

write(dd, repmat(y,1,nch));

4. close the figure.

close(hf);