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Delta

The ** Delta** block performs temporal differentiation of the input signal.

The differentiated signal, *d*, is computed from the input signal, *c*, using the following regression formula:

where *d(t)* is a delta value at time *t* computed in terms of the corresponding input values *c(t-N)* to *c(t+N)*. The value of *N* is set using the parameter `DELTA_WIN`, and defaults to 2.

Since computation of the delta values relies on a window of data around the current input frame, some modification is needed at the very beginning and end of the signal. In this implementation for *t<N* *d(t)=d(N)* and the signal will be truncated by N frames at the end.

Inputs |
Meaning | Sample | 1-D frame | 2-D frame |
---|---|---|---|---|

in1 |
input data | Yes | Yes | Yes |

Outputs |
Meaning |
---|---|

out1 |
data after differentiation |

Parameters |
Type | Default | Meaning |
---|---|---|---|

DELTA_WIN |
Integer | 2 | Half size of the regression window |

Documentation for CTKv1.1.4 - Last modified: Wed Jun 27 16:45:58 BST 2001