From help-request at octave dot org Sat Apr  8 05:50:20 2006
Subject: Re: square waves
From: Paul Kienzle <pkienzle at users dot sourceforge dot net>
To: Doug Stewart <dastew at sympatico dot ca>
Cc: help at octave dot org, NZG <ngustavson@emacinc.com>
Date: Sat, 8 Apr 2006 06:48:14 -0400


On Apr 7, 2006, at 10:12 PM, Doug Stewart wrote:

> NZG wrote:
>
>> Is there a function for generating square waves in octave?
>
> If you know how many 1s and zeros you need then you can do it this way:
>
> a(100)=0;
> b(250)=0;
> b=b+1;
>
> c=[a b a b a b a b]
>
> or do some for loops ;-)


You can vectorize the above:

     n = 8*350;
	x=zeros(1,n);
     x(mod([0:n-1],9)>=100) = 1;

Octave-forge has the compatibility functions pulstran and rectpuls
which can do the same thing:

	n = 8*350;
     x = pulstran([1:n],[101:350:n],'rectpuls',250);

I'm not sure that's any easier though.

See also the function square just added to octave-forge.

- Paul

--

## s = square(t,duty)
##
## Generate a square wave of period 2 pi with limits +1/-1.
##
## If the duty cycle is specified, the square wave is +1 for
## that portion of the time.
##
##                     on time
##    duty cycle = ------------------
##                 on time + off time
##

function v = square (t,duty)

   if nargin == 1,
     duty = .5;
   elseif nargin != 2,
     usage('v = square(t [, duty])');
   endif

   t /= 2*pi;
   v = ones(size(t));
   v(t-floor(t) >= duty) = -1;

endfunction



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