MATLAB实现数据的频域和时域积分代码

function dataout = iomega(datain, dt, datain_type, dataout_type) %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % % IOMEGA is a MATLAB script for converting displacement, velocity, or % acceleration time-series to either displacement, velocity, or % acceleration times-series. The script takes an array of waveform data % (datain), transforms into the frequency-domain in order to more easily % convert into desired output form, and then converts back into the time % domain resulting in output (dataout) that is converted into the desired % form. % % Variables: % ---------- % % datain = input waveform data of type datain_type % % dataout = output waveform data of type dataout_type % % dt = time increment (units of seconds per sample) % % 1 - Displacement % datain_type = 2 - Velocity % 3 - Acceleration % % 1 - Displacement % dataout_type = 2 - Velocity % 3 - Acceleration % % %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % Make sure that datain_type and dataout_type are either 1, 2 or 3 if (datain_type < 1 || datain_type > 3) error('Value for datain_type must be a 1, 2 or 3'); elseif (dataout_type < 1 || dataout_type > 3) error('Value for dataout_type must be a 1, 2 or 3'); end % Determine Number of points (next power of 2), frequency increment % and Nyquist frequency N = 2^nextpow2(max(size(datain))); df = 1/(N*dt); Nyq = 1/(2*dt); % Save frequency array iomega_array = 1i*2*pi*(-Nyq : df : Nyq-df); iomega_exp = dataout_type - datain_type; % Pad datain array with zeros (if needed) size1 = size(datain,1); size2 = size(datain,2); if (N-size1 ~= 0 && N-size2 ~= 0) if size1 > size2 datain = vertcat(datain,zeros(N-size1,1)); else datain = horzcat(datain,zeros(1,N-size2)); end end % Transform datain into frequency domain via FFT and shift output (A) % so that zero-frequency amplitude is in the middle of the array % (instead of the beginning) A = fft(datain); A = fftshift(A); % Convert datain of type datain_type to type dataout_type for j = 1 : N if iomega_array(j) ~= 0 A(j) = A(j) * (iomega_array(j) ^ iomega_exp); else A(j) = complex(0.0,0.0); end end % Shift new frequency-amplitude array back to MATLAB format and % transform back into the time domain via the inverse FFT. A = ifftshift(A); datain = ifft(A); % Remove zeros that were added to datain in order to pad to next % biggerst power of 2 and return dataout. if size1 > size2 dataout = real(datain(1:size1,size2)); else dataout = real(datain(size1,1:size2)); end return