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Altera_Forum's avatar
Altera_Forum
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11 years ago

PWM signal via sine-triangle comparison

Hello, right now i am stuck in aproblem in my project. I hope its not explained to complicated and someone can help me (-: I try to generate a pwm signal out of a sine with 50 Hz - 20ms. I ha...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
11 years ago

Here you are generating a half sine wave. The range of a full wave would be 0 to 2*pi. I also think that the division factor should be 500.0 instead of 499.0. 

for i in 0 to 499 loop	
  x:= SIN(real(i)*MATH_PI/real(499));

You want something like this 

for i in 0 to 499 loop	
  x:= SIN(real(i)*2.0*MATH_PI/500.0);

Secondly, your counters are counting one step too much, e.g. incSineTable counts 498, 499, 500, 0, 1 ...