WA Get Coefficients of 1D Discrete Wavelet Transform (Waveform) VI
- Updated2025-12-08
- 3 minute(s) read
Retrieves approximation or detail discrete wavelet transform (DWT) coefficients at a specific level. Use the WA Discrete Wavelet Transform VI to compute the DWT of a signal. Wire data to the DWT coef input to determine the polymorphic instance to use or manually select the instance.

Inputs/Outputs
coef type
—
coef type specifies whether this VI returns approximation coefficients or detail coefficients. The default is Approximation coefficients.
DWT coef
—
DWT coef specifies the approximation coefficients and the detail coefficients from the multi-level discrete wavelet transform (DWT). You must organize the coefficients into a waveform starting with the approximation coefficients at the largest level followed by the detail coefficients at all levels in descending order.
length
—
length specifies, in a 1D array, the number of approximation and detail coefficients at each level. At a decomposition level of N, length is equal to N+2. The first element of length always is equal to the number of approximation coefficients. The last element of length indicates the total number of raw data samples. You must arrange the length of the detail coefficients in descending order.
coef level
—
coef level specifies the coefficient level this VI returns. The coef level must be between 1 and the largest level of the detail coefficients. The levels in the WA Discrete Wavelet Transform VI specifies the largest level of the coefficients. The default is 1, which means this VI returns the coefficients at level 1.
error in (no error)
—
error in describes error conditions that occur before this node runs. This input provides standard error in functionality.
DWT coef out
—
DWT coef out returns DWT coef unchanged.
length out
—
length out returns length unchanged.
error out
—
error out contains error information. This output provides standard error out functionality.
selected DWT coef
—
selected DWT coef returns the discrete wavelet transform (DWT) coefficients at the coefficient level coef level of the coefficient type coef type. |
Examples
Refer to the following VIs for examples of using the WA Get Coefficients of Discrete Wavelet Transform VI:
- Get and Set Approximation Coefficients VI: labview\examples\Wavelet Analysis\WAGettingStarted
- Get and Set Single Level Detail Coefficients VI: labview\examples\Wavelet Analysis\WAGettingStarted
coef type
—
DWT coef
—
length
—
coef level
—
error in (no error)
—
DWT coef out
—
length out
—
error out
—