RESPITE: The CASA Toolkit Page: Documentation: Block Library Index:Delta


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:

<em>d(t)=  sum i = 1 to N {i.(c(t+i)-c(t-i))}/ sum i=1 to N {2.(I^2)}</em>

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 $\ge$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