![]() ![]() Percussion mode (uses 3 channels to provide 5 percussion sounds).There are also a few parameters that can be set for the whole chip: Attack, decay, sustain, release (4 bits each, logarithmic).Frequency multiply (can be set to 1⁄ 2, 1 to 10, 12 or 15).Feedback (0–7, the modulator modulating itself).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. Its main method of synthesis is frequency modulation synthesis, accomplished via phase modulation of the phase of one channel's oscillators by the output of another. Each oscillator can produce sine waves and has its own ADSR envelope generator. ![]() It can produce 9 channels of sound, each made of two oscillators or 6 channels with 5 percussion instruments available. The circuit has 244 different write-only registers. It is essentially a YM3526 with ADPCM recording and playback capability. ![]() A very closely related chip is the Y8950, or MSX-AUDIO, which was used as an MSX expansion. The YM3526, introduced in 1984, was the first in the OPL family, providing a nine channel, two operator synthesizer. To compute 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.Ĭhips in the series OPL This allows the FM operator to calculate its output without any multipliers, using the formula exp + A 1 ] ] + A 2 ] for values of 0 to 255. Decapsulation of the chips shows two look-up tables, one for calculating exponents and one for log-sine. A low-frequency oscillator and an envelope generator drive an FM operator to produce floating-point output for the DAC. Each FM-tone is generated by a digital oscillator using a form of direct digital synthesis. The internal operation of the chips is completely digital. ![]()
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