expon

Trace an exponential curve between specified points.

Syntax

ares expon ia, idur, ib
kres expon ia, idur, ib

Initialization

ia -- starting value. Zero is illegal for exponentials.

ib -- value after idur seconds. For exponentials, must be non-zero and must agree in sign with ia.

idur -- duration in seconds of the segment. A zero or negative value will cause all initialization to be skipped.

Performance

These units generate control or audio signals whose values can pass through 2 specified points. The idur value may or may not equal the instrument's performance time: a shorter performance will truncate the specified pattern, while a longer one will cause the defined segment to continue on in the same direction.

Examples

Here is an example of the expon opcode. It uses the file expon.csd.

<CsoundSynthesizer>
<CsOptions>
; Select audio/midi flags here according to platform
-odac     ;;;realtime audio out
;-iadc    ;;;uncomment -iadc if realtime audio input is needed too
; For Non-realtime ouput leave only the line below:
; -o expon.wav -W ;;; for file output any platform
</CsOptions>
<CsInstruments>

sr = 44100
ksmps = 32
nchnls = 2
0dbfs  = 1

instr 1 

kpitch = p6
;choose between expon or line
if (kpitch == 0) then   
  kpitch expon p4, p3, p5 
elseif (kpitch == 1) then
  kpitch line p4, p3, p5 
endif

asig   vco2 .6, kpitch 
       outs asig, asig

endin 
</CsInstruments> 
<CsScore> 

i 1 0 2 300 600    0    ;if p6=0 then expon is used
i 1 3 2 300 600    1    ;if p6=1 then line is used
i 1 6 2 600 1200   0
i 1 9 2 600 1200   1
i 1 12 2 1200 2400 0
i 1 15 2 1200 2400 1
i 1 18 2 2400 30   0
i 1 21 2 2400 30   1
e
</CsScore> 
</CsoundSynthesizer> 

See also

Linear and Exponential Generators