Rational Resample VI

Resamples the input signal X by interpolating X, passing the interpolated signal through an FIR filter, and decimating the filtered signal. Wire data to the X input to determine the polymorphic instance to use or manually select the instance.


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The following steps describe the rational resampling process. Each step corresponds to a numbered section of the following image.

  1. Input signal X for resampling. The time interval between two adjacent samples is 1.
  2. Insert zeros between every two adjacent samples to upsample X by the interpolation factor. Let X1 represent the interpolated signal.
  3. Using a FIR filter, filter X1at the start index to obtain the first output sample. The elements outside the range of the interpolated signal equal zero.
  4. Move the filter to the position start index + decimation and filter again to obtain the second output sample.
  5. Repeat step 4, adding each new decimation value until there are not enough samples in X1 for filtering. Store the final samples to internal states and wait for the next signal block. The time interval between two adjacent samples in an output signal is equal to decimation / interpolation. t0 specifies the time of the first output sample.

Examples

Refer to the following example files included with LabVIEW.

  • labview\examples\Signal Processing\Signal Operation\Rational Resampling.vi