# What's the best snipet for get the first batch of fft abs greater than half the maximum?

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Georges Theodosiou 2022 年 10 月 21 日

Dear sirs, pls let me ask your forgive for my previous wrong question. I expect catch first harmonic (FFT's pitch) by catcing the first batch of fft abs greater than half the maximum. I suppose, in human's voice and in violin's sound first harmonic's fft abs is greater than half the maximum, 2.3610e+08 in code. Then by max fucnion catch first harmonic's. What's the best snipet for catch first batch greater than half the "FFTabs"?
SampFreq = 16000;
Segm = 1:2048;
Pitch = 45;
FirstHarmAngles = Pitch*2*pi/SampFreq*Segm+1.9*pi;
SinFirstHarmAngles = sin(FirstHarmAngles);
SecondHarmAngles = Pitch*2*2*pi/SampFreq*Segm+2.9*pi;
SinSecondHarmAngles = sin(SecondHarmAngles);
ThirdHarmAngles = Pitch*3*2*pi/SampFreq*Segm+0.3*pi;
SinThirdHarmAngles = sin(ThirdHarmAngles);
Xn = 170000*SinFirstHarmAngles+220000*SinSecondHarmAngles+150000*...
SinThirdHarmAngles;
FFTXn = fft(Xn,16384);
FFTabs = abs(FFTXn);
plot(FFTabs(1:200));

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### 回答 (1 件)

Georges Theodosiou 2022 年 10 月 26 日

Dear sirs let me answer my qustion.
maxabs = max(FFTabs);
firstBatch = zeros(1,2048);
for a = 1:2048
firstBatch(a) = FFTabs(a);
if FFTabs(a)>maxabs/2 && FFTabs(a+1)<maxabs/2
break
end
end
[maxInFirstBatch, FFTpitch] = max(firstBatch)

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