# 2.1.22.2.1 FFT

## Functions

Name Brief Example
apply_window_data Apply window to the signal Examples
correlation_2d_shift_accumulate Perform 2d correlation on real matrices basing shift-matrix-accumulated algorithm. Examples
create_bandblock_data Generate bandblock Responses data. Examples
create_bandpass_data Generate bandpass Responses data. Examples
create_highpass_data Generate highpass Responses data. Examples
create_lowpass_data Generate lowpass Responses data. Examples
create_response_data Generate Responses data. Examples
FFT These two Functions will do the 1 dimension Fast Fourier Transform. Data matrix should be of type double. If user have the data matrix in integer form, user should first transform it to double using the member function of matrixbase "CastToDouble". Examples
fft_2d_complex Perform 2d complex FFT Examples
fft_2d_correlation Perform 2d correlation on real matrices basing FFT algorithm. Examples
fft_2d_real Performs nFFTRow*nFFTCol-point discrete 2D Fourier transform or 2D inverse Fourier transform. Examples
fft_amp Calculate frequcy and ampilitude. Examples
fft_apply_window Apply a window to a sequence with shift, then get a new sequence of result. Pay atention the start position is not at 0, but at ishift. Examples
fft_complex Performs nFFT-point discrete Fourier transform or inverse Fourier transform. vSig will be padded with zeros if it has less than nFFT points and truncated if it has more. Examples
fft_cosine Performs nFFT-point discrete Fourier Cosine transform. vSig will be padded with zeros if it has less than nFFT points and truncated if it has more. Examples
fft_factor Set the sign of the Exponential Phase factor for the FFT operation. Examples
fft_fft_2d_complex computes the two-dimensional discrete Fourier transform or inverse Fourier transform of a bivariate sequence of complex data values. Examples
fft_fft_2d_correlation Perform 2d correlation on 2 matrices. Examples
fft_fft_2d_real Calculates the 2 dimensional discrete Fourier transforms or inverse 2 dimensional discrete Fourier transforms. Examples
fft_fft_coherence Calculate fft coherence Examples
fft_fft_complex calculates the discrete Fourier transform or inverse Fourier transform of a sequence of iSize complex data values. Examples
fft_fft_convolution calculates the circular convolution of two real vectors of period iSize. Examples
fft_fft_correlation calculates the circular correlation of two real vectors of period iSize. Examples
fft_fft_cosine computes the discrete Cosine transform of iSize real data values. Examples
fft_fft_deconvolution calculates the circular deconvolution of two real vectors of period iSize. Examples
fft_fft_multiple_complex computes the discrete Fourier transforms of iSequences sequences of iSize complex data values. Examples
fft_fft_multiple_real computes the discrete Fourier transforms of iSequences sequences of iSize real data values. For forward FT, each output sequence is in Hermitian form; For backward FT, each input sequence is in Hermitian form. Examples
fft_fft_real calculates the discrete Fourier transform or inverse Fourier transform of a sequence of iSize real data values. For forward FT, the output is in Hermitian form; For backward FT, the input sequence is in Hermitian form. Examples
fft_fft_sine computes the discrete Sine transform of iSize real data values. Examples
fft_get_power_hermitian Caculate the power of a serial of signal sequences which is stored in the input array(vSig). Each signal sequence has the same width. Actually they are the result of FFT transform of a window of source signal as Hermitian-Form. Examples
fft_hermitian_to_complex Convert from Hermitian form to general complex Examples
fft_normalize_response This function performs normalization of the response function Examples
fft_norm_amp Performs amplitude normalization. Examples
fft_one_side_spectrum Compute One Side Spectrum of FFT Result Examples
fft_real Performs nFFT-point discrete Fourier transform or inverse Fourier transform. Examples
fft_sampling_resolution Check the sampling resolution of the frequencies and return the interval of the sequence. Examples
fft_shift This function determines how the transformed data will be presented. Examples
fft_sine Performs nFFT-point discrete Fourier Sine transform. vSig will be padded with zeros if it has less than nFFT points and truncated if it has more Examples
fft_stft Get a amplitude sequence from a signal sequence using Short-Time-Fourier-Transform method. Examples
fft_stft_complex Get a amplitude sequence from a signal sequence using Short-Time-Fourier-Transform method. Examples
fft_unwrap_phase Calculate the change in phi and add it to the previous phase. Examples
fft_wrap_response This function performs wrapping of the response function Examples
fftw_fft_unwrap_phase unwrap phase Examples
fftw_fft_2d_complex Computes the two-dimensional discrete Fourier transform or inverse Fourier transform of a bivariate sequence of complex data values Examples
fftw_fft_complex Calculates the discrete Fourier transform or inverse Fourier transform of a sequence of iSize complex data values Examples
fftw_fft_multiple_complex Computes the discrete Fourier transforms of iSequences sequences of iSize complex data values Examples
get_window_data Generate window signal. Examples
stft_complex Performs Short-Time-Fourier-Transform on a 1d signal(complex data). Examples
stft_real Performs Short-Time-Fourier-Transform on a 1d signal(real data). It computes the windowed discrete-time Fourier transform of a signal using a sliding window. It return the power spectrum from the signal sequence and time and frequence scales as well. Examples
undo_fft_shift This function undoes the results of fft_shift. Examples