Editing Chiptune (section)

== Technology ==
A [[waveform generator]] is a fundamental module in a sound synthesis system. A waveform generator usually produces a basic geometrical waveform with a fixed or variable [[timbre]] and variable pitch. Common waveform generator configurations usually included two or three simple waveforms and often a single [[pseudo-random-noise]] generator (PRNG). Available [[waveform]]s often included [[pulse wave]] (whose [[timbre]] can be varied by modifying the [[duty cycle]]), [[Square wave (waveform)|square wave]] (a symmetrical pulse wave producing only odd overtones), [[triangle wave]] (which has a fixed timbre containing only odd [[harmonic]]s but is softer than a square wave), and [[sawtooth wave]] (which has a bright raspy timbre and contains odd and even harmonics). Two notable examples of systems employing this technology were the [[Game Boy]] portable game console and the [[Commodore 64]] personal computer. The Game Boy uses two pulse channels (switchable between 12.5%, 25%, 50% and 75% wave duty cycle), a channel for a 4-bit waveform generator, and a pseudo-random-noise generator. The Commodore 64 however used the [[MOS Technology SID]] chip which offered 3 channels, each switchable between pulse, saw-tooth, triangle, and noise. Unlike the Game Boy, the pulse channels on the Commodore 64 allowed full control over wave duty cycles. The SID was a very technically advanced chip, offering many other features including ring modulation and adjustable resonance filters.<ref>
{{cite book|last=Waugh|first=I.|title=Commodore 64 Music: Making Music with Your Micro|date=1985|publisher=Sunshine Books}}
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Due to the limited number of voices in early sound chips, one of the main challenges is to produce rich [[polyphonic]] music with them. The usual method to emulate it is via quick [[arpeggio]]s, which is one of the most relevant features of chiptune music (along with its electronic timbres).<ref>{{cite thesis|last=Vegard|first=Kummen|date=2018|title=The Discourse and Culture of Chip Music: Studying the Methods and Values of the Chipscene|type=Master thesis|publisher=University of Agder|url=https://uia.brage.unit.no/uia-xmlui/handle/11250/2565144|access-date=July 2, 2021|archive-date=July 9, 2021|archive-url=https://web.archive.org/web/20210709182256/https://uia.brage.unit.no/uia-xmlui/handle/11250/2565144|url-status=live}}</ref>

Some older systems featured a simple [[Beep (sound)|beeper]] as their only sound output, as the original [[ZX Spectrum]] and [[IBM PC]]; despite this, many skilled programmers were able to produce unexpectedly rich music with this bare hardware, where the sound is fully generated by the system's [[CPU]] by direct control of the beeper.