24 lines
983 B
Mathematica
24 lines
983 B
Mathematica
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function [y,freq,c]=exzfft_ma(x,fe,fs,nfft,D)
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nt=length(x); % ¼ÆËã¶ÁÈëÊý¾Ý³¤¶È
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fi=fe-fs/D/2; % ¼ÆËãϸ»¯½ØֹƵÂÊÏÂÏÞ
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fa=fi+fs/D; % ¼ÆËãϸ»¯½ØֹƵÂÊÉÏÏÞ
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na=round(0.5 * nt/D+1); % È·¶¨µÍͨÂ˲¨Æ÷½ØֹƵÂʶÔÓ¦µÄÆ×ÏßÌõÊý
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% ƵÒÆ
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n=0: nt-1; % ÐòÁÐË÷ÒýºÅ
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b=n*pi* (fi+fa)/fs; % ÉèÖõ¥Î»ÐýתÒò×Ó
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y=x.*exp(-1i*b); % ½øÐÐƵÒÆ
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b= fft(y, nt); % FFT
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% µÍͨÂ˲¨ºÍϲÉÑù
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a(1: na) =b(1: na); % È¡ÕýƵÂʲ¿·ÖµÄµÍƵ³É·Ö
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a(nt-na+2 : nt) =b(nt-na+2 : nt); % È¡¸ºÆµÂʲ¿·ÖµÄµÍƵ³É·Ö
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b=ifft(a, nt); % IFFT
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c=b(1 : D: nt); % ϲÉÑù
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% Çóϸ»¯ÆµÆ×
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y=fft(c, nfft) * 2/nfft;% ÔÙÒ»´ÎFFT
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y=fftshift(y); % ÖØÐÂÅÅÁÐ
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freq=fi+(0:nfft-1)*fs/D/nfft; % ƵÂÊÉèÖÃ
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figure
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plot(freq,20*log10(y))
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grid on
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