About Planet Phatt - E-Mu Planet Phatt Operation Manual

BASIC OPERATION

ABOUT PLANET PHATT

Planet Phatt utilizes digital recordings of real instruments for the basis
of its sound. This is similar to a tape recorder except that inside Planet
Phatt, the sounds are permanently recorded on digital memory chips.
To perform this modern miracle, sounds and instrument waveforms
are first digitally recordered or "sampled". After the sounds and wave-
forms have been truncated, looped and processed, they are "masked"
into the Planet Phatt ROM (Read Only Memory) chips.
Conceptually, the sampling process is very simple, as shown in the
Basic Sampling System diagram. As a sound wave strikes the dia-
phragm of a microphone, a corresponding voltage is generated. To
sample the sound, the voltage level is repeatedly measured at a very
high rate and the voltage measurements are stored in memory. To play
the sound back, the numbers are read back out of memory, converted
back into voltages, then amplified and fed to a speaker which converts
the voltage back into sound waves. Of course, playing back 32 chan-
nels at different pitches tends to complicate matters, but this is basi-
cally how it works. In Planet Phatt, we have left out the Analog/Digital
converter stage since the sounds are already sampled for you.
Analog/Digital
Converter
1011001 1011001
18 Planet Phatt Operation Manual
Basic Sampling System
Planet Phatt
Memory Z-Plane Filter
10100101001
01010010100
10101010100
10101001010
3V
0V
-3V
1V 3V -2V -1V
Digital/Analog Amplifier
Converter
1011001
3V -1V -2V