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YM3812
The OPL (FM Operator Type-L) series are a family of sound chips developed by Yamaha. The OPL series are low-cost sound chips providing FM synthesis for use in computing, music and video game applications. Internal operation 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 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[\varphi_2 + \exp [\log \sin [\varphi_1+ A_1">varphi_2_+_\exp_[\log_\sin_[\varphi_1.html" ;"title="log \sin[\varphi_2 + \exp [\log \sin [\varphi_1">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 r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yamaha YM3526
The OPL (FM Operator Type-L) series are a family of sound chips developed by Yamaha. The OPL series are low-cost sound chips providing FM synthesis for use in computing, music and video game applications. Internal operation 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 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[\varphi_2 + \exp [\log \sin [\varphi_1+ A_1">varphi_2_+_\exp_[\log_\sin_[\varphi_1.html" ;"title="log \sin[\varphi_2 + \exp [\log \sin [\varphi_1">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 r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yamaha YM2413
The YM2413, a.k.a. OPLL, is a cost-reduced FM synthesis sound chip manufactured by Yamaha Corporation and based on their YM3812 (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 also some other cost-cutting modifications: the number of waveforms was reduced to two, additive mode was removed along with the 6-bit carrier volume control (channels instead have 15 levels of volume), and the channels are not mixed using an adder; instead, the chip's built-in DAC uses time-division multiplexing to play short segments of each channel in sequence, which was also done in the YM2612 much later. Applications The YM2413 was used in: * the FM Sound Unit add-on for the Sega Mark III sold exclusively in Japan, that improved the sound quality of all compatible game ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frequency Modulation 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 frequency of an oscillator is altered "in accordance with the amplitude of a modulating signal". FM synthesis can create both harmonic and inharmonic sounds. To synthesize harmonic sounds, the modulating signal must have a harmonic relationship to the original carrier signal. As the amount of frequency modulation increases, the sound grows progressively complex. Through the use of modulators with frequencies that are non-integer multiples of the carrier signal (i.e. inharmonic), inharmonic bell-like and percussive spectra can be created. FM synthesis using analog oscillators may result in pitch instability. However, FM synthesis can also be implemented digitally, which is more stable and became standard practice. Digital FM synthesis (implemented as phase modulation) was the basis of several musical in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 audio signals ( analog and digital signals, for both analog and digital data). They normally contain audio components such as oscillators, envelope controllers, samplers, filters, amplifiers, and envelope generators. History A number of sound synthesis methods for electronically producing sound were devised during the late 20th century. These include programmable sound generators (PSG), wavetable synthesis, and frequency modulation synthesis (FM synthesis). Such sound chips were widely used in arcade game system boards, video game consoles, home computers and digital synthesizers. Since the late-1990s, pulse-code modulation (PCM) sampling has been the standard for many sound chips, as used in the Intel High Definition Audio (IHDA ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Floating Point
In computing, floating-point arithmetic (FP) is arithmetic that represents real numbers approximately, using an integer with a fixed precision, called the significand, scaled by an integer exponent of a fixed base. For example, 12.345 can be represented as a base-ten floating-point number: 12.345 = \underbrace_\text \times \underbrace_\text\!\!\!\!\!\!^ In practice, most floating-point systems use base two, though base ten (decimal floating point) is also common. The term ''floating point'' refers to the fact that the number's radix point can "float" anywhere to the left, right, or between the significant digits of the number. This position is indicated by the exponent, so floating point can be considered a form of scientific notation. A floating-point system can be used to represent, with a fixed number of digits, numbers of very different orders of magnitude — such as the number of meters between galaxies or between protons in an atom. For this reason, floating-poi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Latency (engineering)
Latency, from a general point of view, is a time delay between the cause and the effect of some physical change in the system being observed. Lag, as it is known in gaming circles, refers to the latency between the input to a simulation and the visual or auditory response, often occurring because of network delay in online games. Latency is physically a consequence of the limited velocity at which any physical interaction can propagate. The magnitude of this velocity is always less than or equal to the speed of light. Therefore, every physical system with any physical separation (distance) between cause and effect will experience some sort of latency, regardless of the nature of the stimulation at which it has been exposed to. The precise definition of latency depends on the system being observed or the nature of the simulation. In communications, the lower limit of latency is determined by the medium being used to transfer information. In reliable two-way communication s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Die (integrated Circuit)
A die, in the context of integrated circuits, is a small block of semiconducting material on which a given functional circuit is fabricated. Typically, integrated circuits are produced in large batches on a single wafer of electronic-grade silicon (EGS) or other semiconductor (such as GaAs) through processes such as photolithography. The wafer is cut ( diced) into many pieces, each containing one copy of the circuit. Each of these pieces is called a die. There are three commonly used plural forms: ''dice'', ''dies'' and ''die''. To simplify handling and integration onto a printed circuit board, most dies are packaged in various forms. Manufacturing process Most dies are composed of silicon and used for integrated circuits. The process begins with the production of monocrystalline silicon ingots. These ingots are then sliced into disks with a diameter of up to 300 mm. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Decapping
Decapping (decapsulation) or delidding of an integrated circuit is the process of removing the protective cover or integrated heat spreader (IHS) of an integrated circuit so that the contained die is revealed for visual inspection of the micro circuitry imprinted on the die. This process is typically done in order to debug a manufacturing problem with the chip, or possibly to copy information from the device, to check for counterfeit chips or to reverse engineer it. Companies such as TechInsights and ChipRebel decap, take die shots of, and reverse engineer chips for customers. Modern integrated circuits can be encapsulated in plastic, ceramic, or epoxy packages. Delidding may also be done in an effort to reduce the operating temperatures of an integrated circuit such as a processor, by replacing the thermal interface material (TIM) between the die and the IHS with a higher-quality TIM. With care, it's possible to decap a device and still leave it functional. Method Decapping is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
