&SIGNAL: CONVOLUTE-SIGNALS


TRANSFER-FUNCTION

  The transfer function, which can be specified in either of
  two ways:

  - As a function that depends on the time T, in microsec.
  - As a set of two matrices separated by the word 'VS',
    the first is the values of the transfer function for
    the times listed in the second matrix.

  There is no default transfer function, but the transfer
  function is remembered from one call to the next.

ADD-ON-FUNCTION

  Some transfer functions contain, in the time domain, a delta
  distribution term. This is for instance the case of pole/zero
  filters which have as transfer functions (modulo overall
  constant factors):

         s + 1/t1
  F(s) = -------- ,   F(t) = (1/t1 - 1/t2) * exp(-t/t2) + delta(t)
         s + 1/t2

  To simulate such a filter, one would convolute with exp(-t/t2)
  and add the original signal on top.

  The function to be added is allowed to be a function of the time,
  written as T, and of the signal, written as SIGNAL. In the case
  of the example, one would therefore type

  CONVOLUTE TRANSFER-FUNCTION 0.2*EXP(-T/0.012) ADD SIGNAL

  [By default, no function is added.]

RANGE

  The range over which the transfer function is valid, beyond this
  range the transfer function is set to 0.

  By default, the range is set to [0, 1E10] microsec.

Keyword index. Formatted on 10/11/98.