Wersi CD 600, Assembly Manual

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AM 320-01-808
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5. DSP 160 (Drums)
The PC Board DSP 160 carries the complete drums with all
its instruments like bass drums, snare drums, Hihat, etc.
The drum instruments were digitally recorded in a studio.
This means, each instrument sound was converted into
digital information to be stored in integrated semi-
conductor memories. The contents of these semiconductor
memories can be - following a certain process
- converted into audible sounds as often as required. Cs 9,
10, 11 and 12 on PC Board DSP 160 are such semi-
conductor memories. Reading out these memories
(basically, "replaying" the "recorded" sounds) is done by
the signal processor IC 17 (CPU). This processor, together
with the ICs 9, 10, 11, 12 (=data storage), is a complete 16
bit-computer with internal 32-bit-data processing. One
interface to the outside world is the 16-bit Input Port IC
27/IC 28, which receives the drums trigger signals sent to
the DSP 160 from the organ. These
trigger signals determine which drum instrument is to be
started as well as its volume level.
The second interface to the outside is the digital-analog-
converter IC 6, which is connected to the CPU via the
latches IC 1, 2, 4, and 5. The DIA converter converts the
digital drum sounds into audible analog signals with a
resolution of 16-bit (65535 steps of resolution, similar to
compact disks).
The analog switch IC 14 which follows the converter
guarantees in combination with the sequence control IC 20,
21, 22, 24, 25 that the digital stereo signal at the input of
latches IC 1, 2, 4, 5 is converted into a real audio 2-channel
signal. This signal is routed separately for both channels
via low-pass filters (IC 15 and IC 16), which filter out
unwanted clock frequencies.