Doepfer A-100(~ 40 MB) - Manual (Page 480)

Voltage Addressed T&H/Switch A-152
System A - 100 doepfer
2
2. Basic principles
The sum of the voltages coming from the manual
address control and the CV input define the currently
addressed step of the 3 sub-devices. An address in the
range 1...8 is generated by an internal analog-to-digital
converter. Three address signals (A0, A1 and A2) are
used to address the sub-units multiplexer, T&H and the
digital output section with LED display.
Alternatively the address signals A0, A1 and A2 can be
generated by an internal 3 bit binary counter that is
controlled by the signals clock and reset. For this the
the analog voltage applied to the analog-to-digital con-
verter mentioned above has to remain unchanged as the
CV control has priority over the clock/reset control.
Sub-device #1 is the bidirectional 8-fold multiplexer
(nothing but an electronical 8-fold rotary switch). Bidirec-
tional means that it works into both directions like a
mechanical rotary switch. The common socket may
work as an output that is connected to one of the 8
inputs that are e.g. connected to modulation or audio
sources. But the common socket may even function as
input. In this case the signal applied to the common
socket is output to the currently addressed single socket.
Sub-device #2 is the addressed 8-fold T&H. The signal
at the common T&H input is connected to the addressed
T&H output. The addressed output follows the voltage
applied to the common T&H input (track phase). As
soon as another output is addressed the last voltage is
stored (hold phase).
Remark:
In contrast to the Sample&Hold (see S&H
A-148) the output voltage follows (i.e. tracks) to the input
voltage as long as the corresponding stage (1...8) is
active. Just when the stage is deselected the last voltage
is held. The S&H has only a very short track phase and
picks out a sample of the input voltage within a very
short time.
Sub-device #3 is the digital output section. The digital
output of the currently addressed step turns to "high". All
other digital outputs are low.
The digital output section also drives the LEDs.