Discussion in 'General Electronics Chat' started by u-a-l, Jul 24, 2010.

1. ### u-a-l Thread Starter New Member

Jun 12, 2010
27
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i need some links or pdf about how i can calculate Prompt non-sinusoidal

2. ### tom66 Senior Member

May 9, 2009
2,613
214
What is a "Prompt non-sinusoidal"????

Do you perhaps mean a square wave?

3. ### u-a-l Thread Starter New Member

Jun 12, 2010
27
0
i mean by Prompt non-sinusoidal =
Nonsinusoidal Waveforms

4. ### tom66 Senior Member

May 9, 2009
2,613
214
Well, pretty much anything is non-sinusoidal. Square waves, triangle waves, sawtooth, PWM, PPM. But, due to the Fourier theorem, pretty much any of these waves can be specified with an infinite sum of sine waves at fundamental frequencies.

I could be here for ages. You need to specify what waves you are interested in; it is no good to say "not sine waves".

5. ### u-a-l Thread Starter New Member

Jun 12, 2010
27
0
tem66 i need to calculate harmonic of non-sinusiodal using pic so i have to calculate an , bn , a0 of fourier transformer and that's need funtion of wave and this my proplem

6. ### tom66 Senior Member

May 9, 2009
2,613
214
Calculating a fourier transform on anything other than a dsPIC will not work, there is simply not enough power on one...

A dsPIC or appropriate DSP will work well. These have all the requirements: multiply-accumulate instructions, two 40-bit accumulators, 16-bit shifting and so on.

7. ### u-a-l Thread Starter New Member

Jun 12, 2010
27
0
sorry what the Relationship between ds pic and what i want to do

8. ### maxpower097 Well-Known Member

Feb 20, 2009
795
388
He's saying your pics not powerful enough to do what you want to do. You will need a DSpic to make it work. DSpics are made to process signals and have special functions and hardware to do this. A normal pic does not.

9. ### tom66 Senior Member

May 9, 2009
2,613
214
A dsPIC would be able to do audio fast fourier transforms (FFTs). Just about. I mentioned them because I am personally familiar, though there are plenty of other devices which have an MCU + DSP integrated onto one chip which are capable of what you require. The dsPIC has a whole slew of instructions like accumulate, multiply-accumulate (not to mention hardware multiply and divide assist), barrel shift, indirect addressing and others which make calculating FFTs faster. A standard 8-bit PIC may include an 8x8 hardware multiplier at best; that's simply not enough. A 16-bit PIC includes a 16x16 multiplier and divide assist, but the lack of accumulators makes it less useful. Also, it's important to note you will need a fast clock rate, running a dsPIC33F at 40 MIPS (the maximum speed) should be fast enough.