A programmable sound generator (PSG) is a
sound chip
A sound chip is an integrated circuit (chip) designed to produce audio signals through digital, analog or mixed-mode electronics. Sound chips are typically fabricated on metal–oxide–semiconductor (MOS) mixed-signal chips that process a ...
that generates (or
synthesizes
Chemical synthesis (chemical combination) is the artificial execution of chemical reactions to obtain one or several product (chemistry), products. This occurs by physics, physical and chemical manipulations usually involving one or more reaction ...
) audio wave signals built from one or more basic waveforms, and often some kind of
noise
Noise is sound, chiefly unwanted, unintentional, or harmful sound considered unpleasant, loud, or disruptive to mental or hearing faculties. From a physics standpoint, there is no distinction between noise and desired sound, as both are vibrat ...
. PSGs use a relatively simple method of creating sound compared to other methods such as
frequency modulation synthesis
Frequency modulation synthesis (or FM synthesis) is a form of Synthesizer#Sound synthesis, sound synthesis whereby the frequency of a waveform is changed by Frequency modulation, modulating its frequency with a modulator. The instantaneous frequen ...
or
pulse-code modulation
Pulse-code modulation (PCM) is a method used to digitally represent analog signals. It is the standard form of digital audio in computers, compact discs, digital telephony and other digital audio applications. In a PCM stream, the amplitud ...
.
Technical details
PSGs are controlled by writing data to dedicated
registers on the chip via an external
CPU; hence the name programmable sound generator. One or more basic waveforms are generated (typically a
square
In geometry, a square is a regular polygon, regular quadrilateral. It has four straight sides of equal length and four equal angles. Squares are special cases of rectangles, which have four equal angles, and of rhombuses, which have four equal si ...
, triangle or saw-tooth wave) and often a noise signal. The waveforms' frequency and volume (and noise's tone and volume) are typically shaped using an
envelope
An envelope is a common packaging item, usually made of thin, flat material. It is designed to contain a flat object, such as a letter (message), letter or Greeting card, card.
Traditional envelopes are made from sheets of paper cut to one o ...
and/or mixed before being sent to the audio output stage.
[
Many PSGs feature three tone channels and one noise channel including the AY-3-8910, SN76489 and MOS Technology 6581.
]
History
In the late 1970s, more electronic consumer devices began to be designed with audio features. PSGs were partly developed as a way of incorporating relatively complex sounds at a low cost.[ PSGs were in many ]arcade game
An arcade game or coin-op game is a coin-operated entertainment machine typically installed in public businesses such as restaurants, bars and amusement arcades. Most arcade games are presented as primarily game of skill, games of skill and in ...
s, game console
A video game console is an electronic device that outputs a video signal or image to display a video game that can typically be played with a game controller. These may be home consoles, which are generally placed in a permanent location conne ...
s, and home computer
Home computers were a class of microcomputers that entered the market in 1977 and became common during the 1980s. They were marketed to consumers as affordable and accessible computers that, for the first time, were intended for the use of a s ...
s of the 1980s and 90s.
In 1978, General Instrument released the AY-3-8910, the design of which was later licensed by Yamaha Corporation
is a Japanese multinational musical instrument and audio equipment manufacturer.
It is one of the constituents of Nikkei 225 and is the world's largest musical instrument manufacturing company.
The former motorcycle division was establishe ...
for their YM2149. These chips were used as the standard for the MSX
MSX is a standardized home computer architecture, announced by ASCII Corporation on June 16, 1983. It was initially conceived by Microsoft as a product for the Eastern sector, and jointly marketed by Kazuhiko Nishi, the director at ASCII Corpo ...
computer standards 1 and 2, respectively. The features of this chip were also incorporated into other Yamaha sound chips including the YM2203 and YM2608 chips, these were also capable of FM synthesis
Frequency modulation synthesis (or FM synthesis) is a form of sound synthesis whereby the frequency of a waveform is changed by modulating its frequency with a modulator. The (instantaneous) frequency of an oscillator is altered in accordance wi ...
. In the same year Atari designed the POKEY chip for its home computers and game systems. It incorporated a PSG.Tandy 1000
The Tandy 1000 was the first in a series of IBM PC compatible home computers produced by the Tandy Corporation, sold through its Radio Shack and Radio Shack Computer Center stores. Introduced in 1984, the Tandy 1000 line was designed to offer af ...
.
In 1982, MOS Technology 6581 (SID) was produced for the Commodore 64
The Commodore 64, also known as the C64, is an 8-bit computing, 8-bit home computer introduced in January 1982 by Commodore International (first shown at the Consumer Electronics Show, January 7–10, 1982, in Las Vegas). It has been listed in ...
.Nintendo Entertainment System
The Nintendo Entertainment System (NES) is an 8-bit home video game console developed and marketed by Nintendo. It was first released in Japan on 15 July 1983 as the and was later released as the redesigned NES in several test markets in the ...
, the Ricoh 2A03
The Ricoh 2A03 or RP2A03 ( NTSC version) / Ricoh 2A07 or RP2A07 ( PAL version) is an 8-bit microprocessor manufactured by Ricoh for the Nintendo Entertainment System video game console. It was also used as a sound chip and secondary CPU by Nin ...
, included a PSG.[
]
List of PSGs
See also
* List of sound card standards
* List of Yamaha sound chips
References
{{reflist
Sound chips