Editing Atari 65XEM (section)

== The AMY Synthesizer Chip ==

AMY was a sophisticated single-chip additive synthesizer with the following capabilities:

* ''64 oscillators'' generating sine waves via ROM lookup tables (16-bit)
* ''8 independent output channels'' — oscillators could be combined in pairs to produce up to 8 simultaneous voices
* ''8 frequency ramp generators'' for smooth frequency and amplitude modulation over time
* ''11 octave range''
* ''Random noise generators'' for percussion, explosions, and other wide-spectrum sounds
* ''Digital sound playback'' via Fast Fourier Transform (FFT) — input samples could be analysed and reproduced using the oscillators, achieving telephone-quality voice at just 2,400 baud of bandwidth

The AMY chip was based on the experimental work of Hal Alles at Bell Labs during the 1970s, which had produced a similar additive synthesis system requiring several racks of equipment (the Alles Machine). AMY's system design was led by Gary Sikorski, with Scott Foster as the main architect. Sam Nicolino designed the hardware, John Palevich and Tom Zimmerman contributed to the software.

The AMY would have represented a dramatic improvement over the POKEY chip's 4-channel square wave capabilities, and was considered superior to the Commodore 64's SID chip for music synthesis applications.