distorted sine wave

op

=3D

Your frq_sin value is actually just a phase offset. There is no time associated with this constant to feed the sin(). The phase_temp, on the other hand, is effectively t*incr_sin where t is a cycle count. To see the frequency change, change the incr_sin value instead.

In what way is your sine distorted?

- John_H

loop

:=3D

How can I pass time parameter to the sineWave? I was able to remove the distortion by reducing the incr_sin value. Still not clear on the frequency and time parameter that you are talking about.

Change incr_sin to .1 and look at the difference in the waveform. You are stepping through the sine wave in 6 steps so you will not see what you expect. The wave will look a lot prettier with more steps.

Time is being implied in your phase assignment. But you are not coding the frequency generation correctly.

You code mathematiclly is saying the following y=A*sin(fq+x) x=x+c Where fq is frq_sin, and c is incr_sin the sin wave cycle lasts from 0 to

2PI. There is no time or frequency associated with it. Your fq is just offseting the start point not seting a period. What you want to do is the following. x=x+c y=A*sin(2*PI*fq*x) now remember that x is being incremented in time. fq is in hz. You need to inverse fq to get your period time. which yeilds. x=x+c; y=A*sin(2*PI*x/tp) where tp is the cycle length.

Your code should look like so:

for i in 1 to samples_sin loop result:= scale*(amp_sin*(sin(2.0*PI*frq_sin*phase_temp); sine_real

s loop

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er :=3D

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Phase accumulators are used to mark the prograssion of time. You want sin(f*T) which is sin(f*n*deltaT) where deltaT is your clock period. f*n*deltaT is the same as sum from 1 to n of f*deltaT, this last item being a constant.

That's what you're doing with the incr_sin, isn't it? If you have an increment of 1/100 of a sinusoidal period, the sum of 100 increments will be one sinusoidal period bringing you right back to the beginning.

You *are* doing this for simulation only, aren't you?

- John_H

les loop

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eger :=3D

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This is for simulation only. Thanks for all your comments. I will make the suggested changes and let you guys know how it went.