function?[pkslocspk_wpk_p]?=?hua_fft（Xfsstylevarargin）
%?fs?Sampling?fequency?of?signal
%?hua_fft（Xfsstylevarargin）
%style=1plot?amplitude?value?spectrum；
%style=2plot?power?spectrum;
%style=3plot?loglog
%style=4pwelch?with?segements?number?equals?fsplot?loglog
%style=other?plot?both
%?===========varargin======================
%@@‘FrequencyBan‘[f1f2]
%When?style=1?varargin?input?parameters?can?be?used?to?control?the?frequency?bands
%f1?is?start?frequency
%f2?is?end?frequency
%@@‘Findpeaks‘?is?used?to?control?the?peaks?finding
%@@‘MinPeakHeight‘value
%?please?refer?help?‘findpeaks‘?with?the?same?parameter
%@@‘MinPeakProminence‘value
%?please?refer?help?‘findpeaks‘?with?the?same?parameter
%@@‘MinPeakDistance‘value
%?please?refer?help?‘findpeaks‘?with?the?same?parameter
%@@‘Threshold‘value
%?please?refer?help?‘findpeaks‘?with?the?same?parameter
%?value?=?1e-4?can?exclude?the?flat?peak
%@@‘WindowNum‘value
%windows?number?equal?fs?as?default?if?no?input
%@@‘Overlap‘value
%input?overlap?from?33%~50%?here?take?50%?overlap?as?default
%@@‘Nfft‘?value
%input?number?of?DFT?points?no?less?than?256
%@@‘ustar‘?value
%input?ustar?and?normalize?the?PSD?to?PSD*fs/ustar^2

%http://blog.sina.com.cn/s/blog_574d08530100qu18.html

nfft=?2^nextpow2（length（X））;%set?step?length?automatically
%nfft=1024;%set?step?length?manually
%y=X-mean（X）;
dtr_X=detrend（X）;
y_ft_0=fft（dtr_Xnfft）;%DFTget?amplitude?vaule?distribution
y_ft?=?y_ft_0（1:nfft/2）;?%?throwing?away?half?of?X?:?Nyquist?criteria

Amp?=?2*abs（y_ft）./nfft;???????%Amplitude
mx?=?（abs（y_ft））.^2;????%one-sided?PSD
y_E=（y_ft.*conj（y_ft））./nfft;%compute?the?energy?spectrum
y_p=y_ft.*conj（y_ft）./nfft;??????%Power
fn=fs*（0:nfft/2-1）./nfft;??%frequency?serie

ArgStr?=?varargin;

switch?style
????case?1
????????if?nargin==3
????????????Xvar?=?fn;
????????????Yvar?=?Amp;
????????????plot（XvarYvar）;%use?matlab?help?method?plot?FFT
????????????ylabel（‘Amplitude‘）;xlabel（‘Frequency‘）;%title（‘Spectrum?of?amplitude?value‘）;
????????????%plot（y_fabs（y_ft（1:nfft/2）））;%another?method?to?plot?FFT
????????else
????????????index=?find（strcmp（‘FrequencyBan‘ArgStr））;
????????????if?~isempty（index）
????????????????v_f1=ArgStr{index+1};
????????????????v_fn=ArgStr{index+2};
????????????????ni=round（v_f1?*?nfft/fs+1）;
????????????????na=round（v_fn?*?nfft/fs+1）;
????????????????Xvar?=?fn（ni:na）;
????????????????Yvar?=?abs（y_ft_0（ni:na）*2/nfft）;
????????????????loglog（XvarYvar）;
????????????end
????????end
????????if?nargin?>?3
????????????[arg_strcom4]=?SetArgStr（ArgStr）;
????????????eval_str=?[‘[pkslocspk_wpk_p]=findpeaks（YvarXvar‘arg_strcom4‘‘‘Annotate‘‘‘‘extents‘‘‘‘WidthReference‘‘‘‘halfheight‘‘）;‘];
????????????eval（eval_str