SAC Command Reference Manual

ENVELOPE

SUMMARY

Computes the envelope function using a Hilbert transform.

SYNTAX

ENVELOPE

DESCRIPTION

This command computes the envelope function of the data in memory. The envelope is defined by the square root of x(n)^2 + y(n)^2, where x(n) is the original signal and y(n) its Hilbert transform (see HILBERT). As with HILBERT, very long period datashould be decimated (see DECIMATE) prior to processing.

HEADER CHANGES

DEPMIN, DEPMAX, DEPMEN

SEE COMMANDS

HILBERT, DECIMATE

ACKNOWLEDGEMENT

The subroutines used to perform the Hilbert transform were designed and developed by Dave Harris (DBH).

LATEST REVISION

April 21, 1989 (Version 10.4c)