Yamaha YM2608
Encyclopedia
YM2608, aka OPNA, is a sixteen-channel sound chip
developed by Yamaha. It's a member of Yamaha's OPN family of FM synthesis
chips, and the successor to the YM2203
. It was notably used in NEC's
PC-8801
/PC-9801 series computers.
The YM2608 comprises four internal modules:
The FM Sound Source module includes six concurrent FM channels (voices, twice as many as the Yamaha YM2203
), four operators per channel, with dual interrupt timers
and an LFO
. It also includes eight possible operator interconnections, or algorithms, for producing different types of instrument sounds.
The SSG, or Software-controlled Sound Generator, is Yamaha's YM2149
programmable sound generator. The YM2608 includes the SSG's 3 sound channels and dual 8-bit GPIO ports.
The YM2608 is used with a YM3016
stereo DAC
.
The YMF288, aka OPN3, is a development of the YM2608, used in later NEC PC-9801 computer soundcards. It removes the YM2608's GPIO ports and various deprecated FM functions, and replaces the ADPCM Sound Source with a controllable noise channel. It also reduces the wait times on registry access, and adds a low-power standby mode. The YMF288 also came in a much smaller physical package.
Sound chip
A sound chip is an integrated circuit designed to produce sound . It might be doing this through digital, analog or mixed-mode electronics...
developed by Yamaha. It's a member of Yamaha's OPN family of FM synthesis
Frequency modulation synthesis
A 220 Hz carrier tone modulated by a 440 Hz modulating tone with various choices of modulation index, β. The time domain signals are illustrated above, and the corresponding spectra are shown below ....
chips, and the successor to the YM2203
Yamaha YM2203
The YM2203, aka OPN , is a six-channel sound chip developed by Yamaha. It's the progenitor of Yamaha's OPN family of FM synthesis chips used in many videogame and computer systems throughout the 1980s and early 1990s...
. It was notably used in NEC's
NEC
, a Japanese multinational IT company, has its headquarters in Minato, Tokyo, Japan. NEC, part of the Sumitomo Group, provides information technology and network solutions to business enterprises, communications services providers and government....
PC-8801
NEC PC-8801
The NEC PC-8801 was an early Zilog Z80-based computer exclusively released in Japan, where it became very popular, by NEC Corporation in 1981. It was informally called the "PC-88"....
/PC-9801 series computers.
The YM2608 comprises four internal modules:
- FM Sound Source, an FM synthesisFrequency modulation synthesisA 220 Hz carrier tone modulated by a 440 Hz modulating tone with various choices of modulation index, β. The time domain signals are illustrated above, and the corresponding spectra are shown below ....
sound system, based around the YM2203 - SSG Sound Source, a complete internal SSG implementation
- ADPCM Sound Source, a single 8-bit ADPCMAdaptive DPCMAdaptive differential pulse-code modulation is a variant of differential pulse-code modulation that varies the size of the quantization step, to allow further reduction of the required bandwidth for a given signal-to-noise ratio....
channel, 2-16kHz sampling rateSampling rateThe sampling rate, sample rate, or sampling frequency defines the number of samples per unit of time taken from a continuous signal to make a discrete signal. For time-domain signals, the unit for sampling rate is hertz , sometimes noted as Sa/s... - Rhythm Sound Source, a six-channel ADPCM system, with six percussion "rhythm tones" on a built-in ROM
The FM Sound Source module includes six concurrent FM channels (voices, twice as many as the Yamaha YM2203
Yamaha YM2203
The YM2203, aka OPN , is a six-channel sound chip developed by Yamaha. It's the progenitor of Yamaha's OPN family of FM synthesis chips used in many videogame and computer systems throughout the 1980s and early 1990s...
), four operators per channel, with dual interrupt timers
Programmable Interval Timer
In computing and in embedded systems, a programmable interval timer is a counter which triggers an interrupt when it reaches the programmed count.- Common features :...
and an LFO
Low frequency oscillation
Low-frequency oscillation is an electronic signal, which is usually below 20 Hz and creates a rhythmic pulse or sweep. This pulse or sweep is often used to modulate synthesizers, delay lines and other audio equipment in order to create effects used in the production of electronic music. Audio...
. It also includes eight possible operator interconnections, or algorithms, for producing different types of instrument sounds.
The SSG, or Software-controlled Sound Generator, is Yamaha's YM2149
General Instrument AY-3-8910
The AY-3-8910 is a 3-voice Programmable Sound Generator designed by General Instrument, initially for use with their 16-bit CP1610 or one of the PIC1650 series of 8-bit microcomputers...
programmable sound generator. The YM2608 includes the SSG's 3 sound channels and dual 8-bit GPIO ports.
The YM2608 is used with a YM3016
Yamaha YM3016
thumb|YM3016The YM3016, aka DAC-GS, is a floating point digital-to-analog converter chip developed by Yamaha. It generates stereo analog output from either a two-channel serial or a 16-bit binary/two's complement input, the sound data containing a 10-bit mantissa and 7-bit exponent...
stereo DAC
Digital-to-analog converter
In electronics, a digital-to-analog converter is a device that converts a digital code to an analog signal . An analog-to-digital converter performs the reverse operation...
.
The YMF288, aka OPN3, is a development of the YM2608, used in later NEC PC-9801 computer soundcards. It removes the YM2608's GPIO ports and various deprecated FM functions, and replaces the ADPCM Sound Source with a controllable noise channel. It also reduces the wait times on registry access, and adds a low-power standby mode. The YMF288 also came in a much smaller physical package.