Wersi CD 600, Assembly Manual

Page: 36 / 98

AM 320-01-808
36
7. DH 100 (Digital Reverb Unit, 16 Bit)
Basically, the digital reverb unit DH 100 consists of two
sections:
1. digital section
2. analog section.
The digital section is a complete 16-bit computer consisting
of a 16-bit CPU with 32-bit internal data processing (IC 4),
the program memory (IC 1 & IC 5) and the data storage IC
2/IC 3.
The processing rate of the CPU is determined by the master
clock oscillator XT 1. The XT 1 produces a clock signal of
40 MHz which is divided by 4 in the CPU IC 4 and results
in the bus frequency 10 MHz = 100 ns instruction cycle
time.
The analog signal to be reverberated, which is assigned, to
pin 5 of plug 1 is amplified and routed to the analog switch
IC 16 via a 6-stage lowpass filter. The analog switch
guarantees that the input signal is kept at a con-
stant level while the AID converter IC 13 converts the
analog signal into digital information. The converter
translates the analog input signal (+1-10 volt) into a digital
value with a resolution of 65535 steps. With a sampling
rate of 28 kHz, this value is sent to the CPU IC 4 via the
input latches IC 6 and IC 9.
After processing (computing the reverb) the digital stereo
signal generated in IC 4 is led to the second interface
(output), back to the analog section: the two digital-analog-
converters IC 18 and IC 21. These, again, generate analog
signal from the digital information, the clock frequency
portions of which are filtered out by Iowpass filters.
Now the reverberated stereo signal can be received at the
outputs of IC 20.
IC 8 and IC 10 guarantee exact timing of the read/write
signals for the storage ICs. IC 7, IC 12 and IC 23 produce
the control signals for the two digital-analog converters.