pulse_wave.csd

Pulse Wave and PWM
Jacob Joaquin
October 5, 2010
jacobjoaquin@gmail.com
csoundblog.com

<CsoundSynthesizer>
<CsInstruments>
sr = 44100
kr = 4410
ksmps = 10
nchnls = 1
0dbfs = 1.0

instr 1
    iamp = p4          ; Amplitude
    ipch = cpspch(p5)  ; Pitch
    ipw = p6           ; Pulse width

    ; Pulse wave oscillator
    a1 vco2 iamp, ipch, 2, ipw

    out a1
endin

instr 2
    iamp = p4          ; Amplitude
    ipch = cpspch(p5)  ; Pitch

    ; LFO, for modulating the pulse width of vco2
    klfo lfo 0.475, 0.25, 1
    klfo = klfo + 0.5

    ; Pulse wave oscillator
    a1 vco2 iamp, ipch, 2, klfo

    out a1
endin

</CsInstruments>
<CsScore>

; Pulse waves of varying widths
i 1 0    1 0.5 8.00 0.5   ; Pulse width = 50%, Square wave
i 1 1.5  1 0.5 8.00 0.45  ; 45%
i 1 3    1 0.5 8.00 0.4   ; 40%
i 1 4.5  1 0.5 8.00 0.35  ; etc...
i 1 6    1 0.5 8.00 0.3
i 1 7.5  1 0.5 8.00 0.25
i 1 9    1 0.5 8.00 0.2
i 1 10.5 1 0.5 8.00 0.15
i 1 12   1 0.5 8.00 0.1
i 1 13.5 1 0.5 8.00 0.05

; Pulse width modulation
i 2 16 8 0.5 8.00

</CsScore>
</CsoundSynthesizer>