Questions on the attached example

Hello,

I read this example: http://www.mathworks.com/help/toolbox/daq/brty0qx-1.html

and have a question about it:

Before I put data to 'ao' they use:

data = zeros(4000,1);

why put zeroes to the entire vector? How is it possible that I able to hear any sound after zeroing 'data'?

Thanks,

Answer 1

[Walter Roberson]

The data being used there is example data. Initialize "data" to whatever contents you want (but make sure that it is within range for the device.)

Answer 2

[Michael Adelman]

Hello Walter,

I don't understand, zeroing 'data' is used for initialize only?

Thanks,

[Walter Roberson]

The code example is

data = zeros(4000,1);
putdata(ao,data)
start([ai ao])

Here, "data" is being initialized to something, just for illustration purposes. You could have initialized to 1's or to pi or to 42 if you wanted:

data = 42 * ones(4000,1);
putdata(a0, data);   %queue's the 42's
start(a0);

If you already have a vector, then use it:

putdata(a0, YourColumnVector);
start(a0);

[Michael Adelman]

Thank you