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Goertzel algorithm's amplitude shown in DSP

Started by Nimotsai June 11, 2013
Hello, Elwiz

I am a master student of EE in NSYSU, Taiwan.

I have a problem which the same as the past massage "Goertzel algorithm -
elwiz - 2005-10-25 12:49:00" in your website. 

I use the Goertzel filter to catch 2nd harmonic current written in
DSP28335. And all the results of the 2nd value are proportionally matching
the gain of N/2, i.e., for example, the input current is 0.5A(peak) and
then the value of catching by the algorithm is 83(N=334,
0.5*(N/2)=83.5)shown in the DSP's watch window. 

So my question is that why the value shown in DSP shoult multiply the
gain?
Why the value shown in DSP is not the exactly real current peak value?

Thank you

Best wishes.


sorry, the form is a little bit strange.

83.5 ( N is 334 , 0.5 * ( N / 2 ) is 83.5 )