AF_power_uf(3)

NAME
AF_power_uf, AF_power_af - ULAW and ALAW power tables

SYNTAX
#include <AF/AFUtils.h>

extern float AF_power_uf[];

extern float AF_power_af[];

DESCRIPTION
and are precomputed tables you can link with your application. They are indexed by a ULAW or ALAW sample respectively. The tables contain, effectively, the square of the linearized sample value, scaled to the range from 0.0 to 1.0. These tables are useful for computing the power in a block of ULAW or ALAW compressed samples. This is important for figuring out if the signal is silent or not, for example.

EXAMPLES
Typical usage is:

unsigned char ulaw; float power; power = AF_power_uf[ ulaw ];

DIAGNOSTICS

If you index the table with an out-of-range linear value you
    may cause a protection fault and crash your application.

SEE ALSO
AF(1)

BUGS
If you encounter a reproducible bug, please submit a problem report to (af-bugs@crl.dec.com).

COPYRIGHT
Copyright 1990-1994, Digital Equipment Corporation.
See AF(1) for a full statement of rights and permissions.

AUTHORS
Tom Levergood and Larry Stewart, Digital Cambridge Research Lab