Compute delta features
Audio Toolbox / Features
The Audio Delta block computes the delta of the input audio features. The delta is an approximation of the first derivative of the audio features with respect to time.
Port_1 — Audio features
scalar | vector | matrix | 3-D array
Audio features, specified as a scalar, vector, matrix, or 3-D array. The delta computation operates along the first dimension. All other dimensions are treated as independent channels.
Port_1 — Delta of audio features
scalar | vector | matrix | array
Delta of audio features, returned as an array that is the same size and data type as the input.
Delta window length — Window length over which to calculate delta
9 (default) | odd integer greater than 2
Window length over which to calculate delta, specified as an odd integer greater than 2.
Simulate using — Specify type of simulation to run
Interpreted execution (default) |
Interpreted execution–– Simulate model using the MATLAB® interpreter. This option shortens startup time but has a slower simulation speed than
Code generation. In this mode, you can debug the source code of the block.
Code generation–– Simulate model using generated C code. The first time you run a simulation, Simulink generates C code for the block. The C code is reused for subsequent simulations, as long as the model does not change. This option requires additional startup time, but the speed of the subsequent simulations is comparable to
The delta of an audio feature x is a least-squares approximation of the local slope of a region centered on sample x(k), which includes M samples before the current sample and M samples after the current sample.
The delta window length defines the length of the region from –M to M.
For more information, see .
 Rabiner, Lawrence R., and Ronald W. Schafer. Theory and Applications of Digital Speech Processing. Upper Saddle River, NJ: Pearson, 2010.
C/C++ Code Generation
Generate C and C++ code using Simulink® Coder™.
Introduced in R2022b