Misplaced Pages

#683316

32-624: The OPL series of chips enabled the creation of affordable sound cards in IBM PC compatibles like the AdLib and Sound Blaster , becoming a de-facto standard until they were supplanted by " wavetable synthesis " cards in the early-to-mid 1990s. The internal operation of the chips is completely digital. Each FM-tone is generated by a digital oscillator using a form of direct digital synthesis . A low-frequency oscillator and an envelope generator drive an FM operator to produce floating-point output for

64-406: A & ( ∼ a + 1 ) {\displaystyle a\And (\sim a+1)} , where & {\displaystyle \And } means bitwise operation AND and ∼ {\displaystyle \sim } means bitwise operation NOT on a {\displaystyle a} . For MSb 1 numbering, the value of an unsigned binary integer

96-464: A significant increase in the complexity of tones generated. The drivers for Windows 9x incorporate their own custom instrument patches which make use of this extended mode. Conversely, Legacy mode provides full backward-compatibility with Yamaha's YMF262. ESFM's output in this mode is moderately faithful to the YMF262 overall, but some tones are rendered quite differently, resulting in unique distortions in

128-507: Is limited to nine voices in melodic mode and six voices in percussive mode. Having little competition on the market at the time of introduction of Adlib and Sound Blaster , the chip became the de-facto standard for "Sound Blaster compatible" sound cards. The YM3812 is used with the YM3014B external DAC chip to output its audio in analog form, like with the YM3526. An upgraded version of

160-426: Is not affected by how the value is stored on the device, such as the value's byte order . Rather, it is a property of the numeric value in binary itself. This is often utilized in programming via bit shifting : A value of 1 << n corresponds to the n bit of a binary integer (with a value of 2 ). In digital steganography , sensitive messages may be concealed by manipulating and storing information in

192-414: Is the convention used to identify the bit positions in a binary number . In computing , the least significant bit ( LSb ) is the bit position in a binary integer representing the binary 1s place of the integer. Similarly, the most significant bit ( MSb ) represents the highest-order place of the binary integer. The LSb is sometimes referred to as the low-order bit or right-most bit , due to

224-581: The YMF278 ( OPL4 ), the single-chip Yamaha YMF718/719S, and the PCI YMF724/74x family, included the YMF262's FM synthesis block for backward compatibility with legacy software. See YMF7xx for more information. The YM3526 was notably used in a Commodore 64 expansion, the Sound Expander , as well as several arcade games , such as Terra Cresta and Bubble Bobble . A modified version of

256-400: The two's complement method. The MSb most significant bit has a negative weight in signed integers, in this case -2 = -128. The other bits have positive weights. The lsb ( least significant bit ) has weight 2 =1. The signed value is in this case -128+2 = -126. The expressions most significant bit first and least significant bit at last are indications on the ordering of the sequence of

288-767: The DAC. Decapsulation of the chips shows two look-up tables, one for calculating exponents and one for log-sine. This allows the FM operator to calculate its output without any multipliers, using the formula exp ⁡ [ log ⁡ sin ⁡ [ φ 2 + exp ⁡ [ log ⁡ sin ⁡ [ φ 1 ] + A 1 ] ] + A 2 ] {\displaystyle \exp[\log \sin[\varphi _{2}+\exp[\log \sin[\varphi _{1}]+A_{1}]]+A_{2}]} and two 256-entry look-up tables. Both tables are stored as pairs of values rounded to

320-834: The MSX-MUSIC standard, which was released both as separate enhancement cards (such as the Panasonic FM-PAC) and built-in into several MSX2+ and the MSX TurboR computers. The YMF262 was used in many IBM PC-based sound cards , firstly with the popular Sound Blaster Pro 2 in 1991 and then later with the Sound Blaster 16 ASP in 1992, as well as the Pro AudioSpectrum (16bit). Later models of the Sound Blaster 16 and Sound Blaster AWE series integrated

352-581: The OPL2, the YMF262 (a.k.a. OPL3 ), was released in 1990. It improved upon the feature-set of the YM3812, using four-operator FM synthesis, which produces harmonically richer sound similar to contemporary consumer synthesizer keyboards such as Yamaha DX100 . The following features were added: The YMF262 also removed support for the little-used CSM (Composite sine mode), featured on the YM3812 and YM3526. The mode

SECTION 10

#1732790295684

384-648: The OPL3 was written in SystemVerilog and adapted to an FPGA in 2015. Sound cards Too Many Requests If you report this error to the Wikimedia System Administrators, please include the details below. Request from 172.68.168.226 via cp1108 cp1108, Varnish XID 251880301 Upstream caches: cp1108 int Error: 429, Too Many Requests at Thu, 28 Nov 2024 10:38:15 GMT Least significant bit In computing , bit numbering

416-797: The OPL3 with other chips, with Creative Labs using an OPL3 clone chip, the CQM, integral with other chips in later models from late 1995. It is also used in several arcade games by Tecmo and others. The YMF278 was used in the Moonsound card for the MSX, as well as the SoundEdge card by Yamaha for IBM PC compatibles. Synthesizers that use the YM3812: Synthesizers that use the YM2413 (cost reduced YM3812): An open-source RTL implementation of

448-726: The YM3526 with ADPCM audio known as the Y8950 (MSX-AUDIO) was used in the MSX computer as an optional expansion. The YM3812 saw wide use in IBM PC -based sound cards such as the AdLib , Sound Blaster and Pro AudioSpectrum (8bit) , as well as several arcade games by Nichibutsu , Toaplan and others. The YM2413 was used in the FM Sound Unit expansion for the Sega Mark III and the Japanese model Sega Master System , as well as

480-516: The bit number and a base of 2. The value of an unsigned binary integer is therefore where b i denotes the value of the bit with number i , and N denotes the number of bits in total. When the bit numbering starts at zero for the most significant bit (MSb) the numbering scheme is called MSb 0 . The value of an unsigned binary integer is therefore LSb of a number can be calculated with time complexity of O ( n ) {\displaystyle O(n)} with formula

512-433: The bits in the bytes sent over a wire in a serial transmission protocol or in a stream (e.g. an audio stream). Most significant bit first means that the most significant bit will arrive first: hence e.g. the hexadecimal number 0x12 , 00010010 in binary representation, will arrive as the sequence 0 0 0 1 0 0 1 0 . Least significant bit first means that the least significant bit will arrive first: hence e.g.

544-574: The color. In this diagram, green is represented by its RGB value, both in decimal and in binary. The red box surrounding the last two bits illustrates the least significant bits changed in the binary representation. This table illustrates an example of decimal value of 149 and the location of LSb. In this particular example, the position of unit value (decimal 1 or 0) is located in bit position 0 (n = 0). MSb stands for most significant bit , while LSb stands for least significant bit . This table illustrates an example of an 8 bit signed decimal value using

576-460: The convention in positional notation of writing less significant digits further to the right. The MSb is similarly referred to as the high-order bit or left-most bit . In both cases, the LSb and MSb correlate directly to the least significant digit and most significant digit of a decimal integer. Bit indexing correlates to the positional notation of the value in base 2. For this reason, bit index

608-499: The exponent, 1024 is added to the value at the index given by the least significant byte of input; this becomes the significand and the remaining bits of input become the exponent of the floating point output. The YM3526 , introduced in 1984, was the first in the OPL family, providing a nine channel, two operator synthesizer. A very closely related chip is the Y8950 , or MSX-AUDIO , which

640-436: The feature-set of the YMF262, with a number of differences: ESS Technology 's in-house developed derivative, termed ESFM , is an enhanced 72-operator OPL3-compatible clone incorporating two operating modes, a Native mode and a Legacy mode, which controls its feature-set and behavior. In Native mode, ESFM allows 18 4-operator FM voices to be mapped, each with per-operator frequency control and LFO depth, potentially allowing for

672-433: The least significant bits of an image or a sound file. The user may later recover this information by extracting the least significant bits of the manipulated pixels to recover the original message. This allows the storage or transfer of digital information to remain concealed. [REDACTED] A diagram showing how manipulating the least significant bits of a color can have a very subtle and generally unnoticeable affect on

SECTION 20

#1732790295684

704-551: The logarithmic scale signal back to linear scale when required, as the final stage where the oscillator-outputs are summed together (just prior to the DAC-output bus), with the modulator waveform always delayed by one sample before the carrier waveform. This table is computed by ( 2 x 256 − 1 ) × 1024 {\displaystyle \left({\frac {2^{x}}{256}}-1\right)\times 1024} for values of 0 to 255. To compute

736-605: The nearest whole number, with the second value represented as the difference between it and the first value. A quarter of the log-transformed sine waveform is stored as a sampled approximation in a 256- word read-only memory (ROM) table, computed by 256 × − log 2 ⁡ ( sin ⁡ ( ( x + 0.5 ) × π 512 ) ) {\displaystyle 256\times -\log _{2}\left(\sin \left({\frac {(x+0.5)\times \pi }{512}}\right)\right)} for values of 0 to 255. The rest of

768-418: The negative part of the sine is muted), absolute-sine waves (where the negative part is inverted), and pseudo-sawtooth waves (quarter sine waves upward only with silent sections in between). This odd way of producing waveforms give the YM3812 a characteristic sound. Limited to two-operator FM synthesis, the chip is unable to accurately reproduce timbres of real instruments and percussive sounds. Melody polyphony

800-462: The original OPL3. Yamaha also produced a fully compatible, low-power variant of the YMF262 in 1995 called the YMF289 (OPL3-L), which targeted PCMCIA sound cards and laptop computers. It was used in some Sound Blaster 16 sound cards made by Creative Technology . The YMF289B is paired with a YAC513 or YAC516 companion floating-point DAC chip. The YMF289 is fully register-compatible with and retains

832-422: The phase of one channel's oscillators by the output of another. The YM3526's output, a sequence of floating point numbers clocked at a sampling frequency of approximately 49716 Hz, is sent to a separate digital-to-analog converter (DAC) chip, the YM3014B. Overview of a channel's registers: For the whole channel: For each one of the two oscillators: There are also a few parameters that can be set for

864-414: The same hexadecimal number 0x12 , again 00010010 in binary representation, will arrive as the (reversed) sequence 0 1 0 0 1 0 0 0 . When the bit numbering starts at zero for the least significant bit (LSb) the numbering scheme is called LSb 0 . This bit numbering method has the advantage that for any unsigned number the value of the number can be calculated by using exponentiation with

896-403: The sine-waveform is extrapolated via its property of symmetry. Scaling the output of an oscillator to a wanted volume would normally be done by multiplication, but the YM3526 avoids multiplications by operating on log-transformed signals, which reduces multiplications into computationally cheaper additions. Another 256-word ROM stores the exponential function as a lookup table, used to convert

928-636: The sound and music of some games. ESFM is available in ESS sound chips starting with the ISA-based ES1688 AudioDrive, up to the PCI-based ES1946 Solo-1E, whereas earlier chips required an external FM synthesizer chip (typically a Yamaha YMF262). ESS's Maestro series of PCI-based sound chips rely on a software implementation of FM synthesis that lacks ESFM's special features. Yamaha's later PC audio controllers, including

960-589: The whole chip: In 1985, Yamaha created the YM3812 , also known as the OPL2 . It is backward compatible with the YM3526. Another related chip is the YM2413 (OPLL), which is a cut down version. Among its newly-added features is the ability to pick between four waveforms for each individual oscillator by setting a register. In addition to the original sine wave, three modified waveforms can be produced: half-sine waves (where

992-646: Was equivalent to triggering multiple channels simultaneously. The YMF262's FM synthesis mode can be configured in different ways: Like its predecessors, the OPL3 outputs audio in digital-I/O form, requiring an external DAC chip such as the YAC512. The YMF262 was used in the revised Sound Blaster Pro , Sound Blaster 16 , AdLib Gold , Media Vision ’s Pro AudioSpectrum cards , and Microsoft ’s Windows Sound System cards . Competing sound chip vendors (such as ESS, OPTi, Crystal and others) designed their own OPL3-compatible audio chips, with varying degrees of faithfulness to

Yamaha OPL - Misplaced Pages Continue

1024-471: Was used as an MSX expansion. It is essentially a YM3526 with ADPCM recording and playback capability. The circuit has 244 different write-only registers . It can produce 9 channels of sound, each made of two oscillators or 6 channels with 5 percussion instruments available. Each oscillator can produce sine waves and has its own ADSR envelope generator . Its main method of synthesis is frequency modulation synthesis , accomplished via phase modulation of

#683316