/*���f���^*/
typedef struct {
    double real;
    double image;
} dcomplex_t;

typedef struct {
    int frequency;
    double power;
} powerspec_t;

#ifndef M_PI
#define M_PI 3.14159265358979
#endif

void real2cmp(double r[],dcomplex_t c[],int size);
void hanning(dcomplex_t data[],int size);
void expand(dcomplex_t x[],int size);
void rectwindow(dcomplex_t data[],int size,int lowerlimit,int upperlimit);
void makepower(dcomplex_t s[],double pow[],int size,int mode);
void fft(int cdir,dcomplex_t x[],int size);
void initfft(int fftsize);
void postfft(void);

void calcPowerspectrum(double timedomain[],int size,long int samplingfrequency,powerspec_t powerspec[]);