ares poscil aamp, acps, ifn [, iphs]
ares poscil aamp, kcps, ifn [, iphs]
ares poscil kamp, acps, ifn [, iphs]
ares poscil kamp, kcps, ifn [, iphs]
ires poscil kamp, kcps, ifn [, iphs]
kres poscil kamp, kcps, ifn [, iphs]
ifn -- function table number
iphs (optional, default=0) -- initial phase (in samples)
ares -- output signal
kamp, aamp -- the amplitude of the output signal.
kcps, acps -- the frequency of the output signal in cycles per second.
poscil (precise oscillator) is the same as oscili, but allows much more precise frequency control, especially when using long tables and low frequency values. It uses floating-point table indexing, instead of integer math, like oscil and oscili. It is only a bit slower than oscili.
Since Csound 4.22, poscil can accept also negative frequency values and use a-rate values both for amplitude and frequency. So both AM and FM are allowed using this opcode.
Here is an example of the poscil opcode. It uses the files poscil.orc and poscil.sco.
Example 279. Example of the poscil opcode.
/* poscil.orc */ ; Initialize the global variables. sr = 44100 kr = 4410 ksmps = 10 nchnls = 1 ; Instrument #1 - a basic oscillator. instr 1 kamp = 10000 kcps = 440 ifn = 1 a1 poscil kamp, kcps, ifn out a1 endin /* poscil.orc */
/* poscil.sco */ ; Table #1, a sine wave. f 1 0 16384 10 1 ; Play Instrument #1 for 2 seconds. i 1 0 2 e /* poscil.sco */