The YM2413, aka OPLL, is a cost-reduced 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 ....

 sound chip

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...

 manufactured by Yamaha Corporation and based on their YM3812

Yamaha YM3812

The Yamaha YM3812 also known as the OPL2 is a sound chip created by Yamaha Corporation in 1985 and famous for its wide use in IBM PC-based sound cards such as the AdLib and Sound Blaster.It is backwards compatible with the OPL aka YM3526, to which it is very similar – in fact, it only adds 3 new...

 (OPL2). To make the chip cheaper to manufacture, many of the internal registers were removed. The result of this is that the YM2413 can only play one user-defined instrument at a time; the other 15 instrument settings are hard-coded and cannot be altered by the user. There were other cost-cutting modifications: the number of waveform

Waveform

Waveform means the shape and form of a signal such as a wave moving in a physical medium or an abstract representation.In many cases the medium in which the wave is being propagated does not permit a direct visual image of the form. In these cases, the term 'waveform' refers to the shape of a graph...

s was reduced to two, and an adder

Adder (electronics)

In electronics, an adder or summer is a digital circuit that performs addition of numbers.In many computers and other kinds of processors, adders are used not only in the arithmetic logic unit, but also in other parts of the processor, where they are used to calculate addresses, table indices, and...

 is not used to mix the channels; instead, the chip's 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...

 plays each channel one after the other, and the output of this is usually passed through an analog filter

Audio filter

An audio filter is a frequency dependent amplifier circuit, working in the audio frequency range, 0 Hz to beyond 20 kHz. Many types of filters exist for applications including graphic equalizers, synthesizers, sound effects, CD players and virtual reality systems.Being a frequency dependent...

.

List of YM2413 Applications

• The YM2413 was used on the MSX-Music sound expansion on the MSX
  MSX
  MSX was the name of a standardized home computer architecture in the 1980s conceived by Kazuhiko Nishi, then Vice-president at Microsoft Japan and Director at ASCII Corporation...
  
   and on the Sega SG-1000 Mark III / Master System
  Sega Master System
  The is a third-generation video game console that was manufactured and released by Sega in 1985 in Japan , 1986 in North America and 1987 in Europe....
  
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• The YM2413 was used in the Yamaha PSR-6 keyboard (ca. 1989).
• Konami's VRC7 soundchip is a YM2413 derivative, used exclusively on the NES
  Nes
  -Localities:In Norway:* Nes, Akershus, a municipality in the county of Akershus in Norway* Nes, Buskerud, a municipality in the county of Buskerud in Norway* Nes, Hedmark, a former municipality in the county of Hedmark in Norway...
  
   game Lagrange Point
  Lagrange Point (video game)
  is an RPG game by Konami, released only in Japan in 1991.-Summary:The name of the video game references Lagrangian points, the five positions in space where a body of negligible mass could be placed which would then maintain its position relative to two existing massive bodies.Lagrange Point has...
  
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