Programmer Guide/SPU Reference/ADDSYN

ADDSYN - additive synthesis

Usage:

ADDSYN sr l f a p nc df da

Inputs:

sr	sampling rate in Hz
l	length of output buffer (number of samples / evaluation cycle)
f	frequency in Hz
amp	amplitude(s) (linear)
p	phase (initial phase settings)
nc	number of components
df	frequency/ies increment in Hz
da	magnitude factor

Outputs:

y	number (l=1) or vector (l>1), synthesized signal

Function:

This atom using additive synthesis of sine waves to generate a signal. The signal of sampling rate sr is stored in the output y. The inputs (except p and nc) are updated at the beginning of each evaluation cycle to allow modulations. For the additive synthesis the following formula is used:

with:

Number of components ():
	f and amp are numbers	is set to value of input nc (>0)
	f is a number, amp is a vector	is set length of amp
	f is a vector, amp is a number	is set length of f
Component frequencies ():
	f is a number	= f + i.df
	f is a vector	= f[i]
Component amplitudes (ai):
	amp is a number	ai = amp.dai
	amp is a vector	ai = amp[i]
Initial phases of components (ji):
	p is a number		ji = p
	p is a vector		ji = p[i]
	p is a string:	p=SIN	ji = 0
		p=COS	ji = p / 2
		p=SINCOS	ji = 0 if i is even and p/2 otherwise
		p=COSSIN	ji = p/2 if i is even and 0 otherwise