AF_power_uf(3)						       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
  AF_power_uf and AF_power_af 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 comput-
  ing 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