.nf
	kr	\fBoscil\fR	kamp, kcps, ifn[, iphs]
	kr	\fBoscili\fR	kamp, kcps, ifn[, iphs]
	ar	\fBoscil\fR	xamp, xcps, ifn[, iphs]
	ar	\fBoscili\fR	xamp, xcps, ifn[, iphs]
	ar	\fBfoscil\fR	xamp, kcps, kcar, kmod, kndx, ifn[, iphs]
	ar	\fBfoscili\fR	xamp, kcps, kcar, kmod, kndx, ifn[, iphs]
.fi

Table \fIifn\fR is incrementally sampled modulo the table length and the
value obtained is multiplied by \fIamp\fR.


INITIALIZATION

\fIifn\fR - function table number.  Requires a wrap-around guard point.

\fIiphs\fR (optional) - initial phase of sampling, expressed as a fraction of
a cycle (0 to 1).
A negative value will cause phase initialization to be skipped.
The default value is 0.


PERFORMANCE

The 
.B oscil
units output periodic control (or audio) signals consisting of the  value of 
.I kamp (xamp)
times the value returned from control rate
(audio rate) sampling of a stored function table.  The internal  phase
is  simultaneously  advanced in accordance with the
.I cps
input value.
While the amplitude and frequency inputs to the K-rate \fBoscil\fRs are
scalar only, the corresponding inputs to the audio-rate \fBoscil\fRs may
each be either scalar or vector, thus permitting amplitude and frequency
modulation at either sub-audio or audio frequencies.

.B foscil
is a composite unit that effectively banks two \fBoscil\fRs in the
familiar Chowning FM setup, wherein the audio-rate output of one generator
is used to modulate the frequency input of another (the "carrier").
Effective carrier frequency =
.I kcps*kcar,
and modulating frequency =
.I kcps*kmod.
For integral values of
.I kcar
and
.I kmod,
the perceived fundamental will be the
minimum positive value of
.I
kcps * (kcar - n*kmod), n = 0,1,2,...
.R
The input
.I kndx
is the index of modulation (usually time-varying and ranging
0 to 4 or so) which determines the spread of acoustic energy over the partial
positions given by n = 0,1,2,..,etc.
.I ifn
should point to a stored sine wave.

.B oscili
and
.B foscili
differ from
.B oscil
and
.B foscil
respectively in that the standard procedure of using a truncated phase
as a sampling index is here replaced by a process that  interpolates between
two successive lookups.  Interpolating generators will produce a noticeably
cleaner output signal, but they may take as much as twice as long to run.
Adequate accuracy can also be gained without the time cost of interpolation
by using large stored function tables of 2K, 4K or 8K points if the space is
available.

.nf
Example:

	k1	oscil	10, 5, 1			;5 cps vibrato
	a1	oscil	5000, 440+k1, 1		;around A440 +-10 cps
.fi
.bp