man3/AFSingleTone.3

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    AFSingleTone(3)						      AFSingleTone(3)

    NAME
      AFSingleTone - generate a tone

    SYNTAX
      #include <AF/AFUtils.h>

      extern double	AFSingleTone(double freq, double peak,
    					  double phase,
    					  float	*buffer, int length);

    DESCRIPTION
      AFSingleTone is a flexible subroutine	for generating and combining sinewave
      signals.  The	generated signal is ADDED into the output buffer, so the
      client of this procedure has the responsibility for initially	zeroing	the
      buffer.  Multiple tones can be generated by repeated calls.

    ARGUMENTS

      freq is the desired digital frequency, expressed as a	fraction of the	sam-
           pling rate.  The	value should be	in the range 0.0 to 0.5.

      peak is the peak value of the	sine wave desired.

      phase
           is the initial phase desired.  This should be in	the range
           [0.0..1024.0).  It is used as an	initial	index into the sine wave
           table AF_sine_float(3).	The return value from AFSingleTone is the
           final phase.  If	the return value is passed to a	second invocation of
           AFSingleTone, the resulting wave	will be	continuous at the boundary.

      buffer
           is a pointer to the signal buffer that will be filled in	by
           AFTonePair.

      length
           is the length of	the block desired.

    SEE ALSO
      AF_sine_float(3), AFTonePair(3), AFDialPhone(3)
      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
      Larry	Stewart, Digital Cambridge Research Lab