//?fft?--?a?program?to?model?a?Fast?Fourier?Transform?（FFT）.
//
//?Copyright?（C）?2001?John?Dalton
//
//?This?program?is?free?software;?you?can?redistribute?it?and/or?modify
//?it?under?the?terms?of?the?GNU?General?Public?License?as?published?by
//?the?Free?Software?Foundation;?either?version?2?of?the?License?or
//?（at?your?option）?any?later?version.
//
//?This?program?is?distributed?in?the?hope?that?it?will?be?useful
//?but?WITHOUT?ANY?WARRANTY;?without?even?the?implied?warranty?of
//?MERCHANTABILITY?or?FITNESS?FOR?A?PARTICULAR?PURPOSE.??See?the
//?GNU?General?Public?License?for?more?details.
//
//?You?should?have?received?a?copy?of?the?GNU?General?Public?License
//?along?with?this?program;?if?not?write?to?the?Free?Software
//?Foundation?Inc.?59?Temple?Place?-?Suite?330?Boston?MA?02111-1307?USA.



//?Include?required?libraries

#include?
#include?
#include?
#include?
#include?


//
//?factor
//
//?Return?a?factor?of?a?number.
//
//?Inputs:??x?=?the?number?to?be?factored.
//?Returns:?A?factor?of?‘x‘.??If?‘x‘?is?a
//??????????prime?eith?‘x‘?or?the?number
//??????????one?will?be?returned.
//
long?factor（long?x）
{
??long?i;

??for（i=2;?i????if（x%i==0）?{
??????return（i）;
????}
??}
??return（1）;
}


//Paramatise?the?type?of?each?element
//to?allow?it?to?be?changed?easily

#define?element_type?double_complex


//This?routine?does?one?stage?of?an?FFT.

//
//?fft_stage
//
//?Do?a?set?of?FFTs.??The?length?of?the?FFT?may?be
//?smaller?than?the?length?of?the?input?sequence.
//?In?this?case?multiple?FFTs?will?be?performed.
//?If?the?length?of?the?FFT?is?a?composite?number
//?it?is?recusively?decomposed?into?smaller?FFTs
//?whose?lengths?are?prime?numbers.??The?elements
//?of?each?FFT?do?not?need?to?be?consecutive.
//
//?Inputs:??in?=?A?sequence?of?numbers?to?be?transformed.
//??????????fft_length?=?The?number?of?points?in?each?FFT
//??????????grouping?=?The?separation?between?each?element
//?????????????????????within?an?FFT.
//?Returns:?The?transformed?sequence.
//
vector?fft_stage（vector?in?int?fft_length?int?grouping）
{
??int?x?y;
??vector?out（in.size（））;
??int?f;

??//??cout<<“***FFT“<
??//?A?DFT?of?length?does?nothing?so?just
??//?return?the?input
??if（fft_length?<=1）?{
????out?=?in;
????return（out）;
??}

??//?Factorise?the?number?of?points?in?the?DFT?（if?possible）
??//?so?we?can?break?it?into?two?smaller?DFTs
??f?=?factor（fft_length）;

??//?If?the?number?of?points?in?the?DFT?is?a?composite
??//?number?（ie.?can?be?factorised）?divide?it?into
??//?two?smaller?DFTs.??Recurse?until?the?DFT?has?been
??//?decomposed?into?DTFs?of?prime?length.
??if（f!=fft_length?&&f!=1）?{
????int?P?=?f;
????int?Q?=?fft_length?/?f;
????vector?intermediate（in.size（））;

????//Do?a?DFT?along?one?dimension
????intermediate?=?fft_stage（in?P?grouping*Q）;
????//Multiply?by?twiddle?fact

?屬性????????????大小?????日期????時(shí)間???名稱(chēng)
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?????文件???????9747??2007-08-13?12:59??用FPGA實(shí)現(xiàn)FFT算法\用fpga實(shí)現(xiàn)fft算法\fft.cpp

?????文件??????12322??2007-08-13?13:00??用FPGA實(shí)現(xiàn)FFT算法\用fpga實(shí)現(xiàn)fft算法\fft.v

?????文件?????221919??2007-08-13?13:15??用FPGA實(shí)現(xiàn)FFT算法\用fpga實(shí)現(xiàn)fft算法\一種基于FPGA的數(shù)字化頻譜分析技術(shù).pdf

?????文件?????160908??2007-08-13?12:07??用FPGA實(shí)現(xiàn)FFT算法\用fpga實(shí)現(xiàn)fft算法\基于Cyclone系列FPGA的1024點(diǎn)FFT算法的實(shí)現(xiàn).pdf

?????文件?????156177??2007-08-13?12:06??用FPGA實(shí)現(xiàn)FFT算法\用fpga實(shí)現(xiàn)fft算法\基于DSP技術(shù)的虛擬式FFT頻譜分析儀.pdf

?????文件??????18449??2007-08-13?12:38??用FPGA實(shí)現(xiàn)FFT算法\用fpga實(shí)現(xiàn)fft算法\基于FPGA的快速傅立葉變換.htm

?????目錄??????????0??2008-04-02?18:07??用FPGA實(shí)現(xiàn)FFT算法\用fpga實(shí)現(xiàn)fft算法

?????目錄??????????0??2008-05-10?11:17??用FPGA實(shí)現(xiàn)FFT算法

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