Mackie d8b v3, Service Manual

Page: 20 / 117

20
DSP SIGNAL FLOW
TAPE CARDS
DR4 8_IN_HOT
DIGITAL
NAME
ANALOG
INPUT
8 GND
DR4 7_IN_COLD
DR3 6_IN_HOT
1_IN_COLD DR1
2 GND
2_IN_HOT DR1
3_IN_COLD DR2
4 GND
4_IN_COLD DR2
5_IN_COLD DR3
6 GND
J101-1
J101-2
J101-3
J101-4
J101-12
J101-11
J101-10
J101-9
J101-8
J101-7
J101-6
J101-5
DR4 8_IN_COLD
DR4 7_IN_HOT
7 GND
1_IN_HOT DR1
2_IN_COLD DR1
3 GND
3_IN_HOT DR2
4_IN_COLD DR2
5 GND
5_IN_HOT DR3
6_IN_COLD DR3
J101-13
J101-14
J101-15
J101-16
J101-24
1 GND J101-25
J101-23
J101-22
J101-21
J101-20
J101-19
J101-18
J101-17
DT4 8_OUT_HOT
DB25
Connector/pin DB25
Connector/pin
DIGITAL
NAME
ANALOG
OUTPUT
8 GND
DT4 7_OUT_COLD
DT3 6_OUT_HOT
1_OUT_COLD DT1
2 GND
2_OUT_HOT DT1
3_OUT_COLD DT2
4 GND
4_OUT_COLD DT2
5_OUT_COLD DT3
6 GND
J102-1
J102-2
J102-3
J102-4
J102-12
J102-11
J102-10
J102-9
J102-8
J102-7
J102-6
J102-5
DT4 8_OUT_COLD
DT4 7_OUT_HOT
7 GND
1_OUT_HOT DT1
2_OUT_COLD DT1
3 GND
3_OUT_HOT DT2
4_OUT_COLD DT2
5 GND
5_OUT_HOT DT3
6_OUT_COLD DT3
J102-13
J102-14
J102-15
J102-16
J102-24
1 GND J102-25
J102-23
J102-22
J102-21
J102-20
J102-19
J102-18
J102-17
This shows the analog inputs and outputs on the Tape cards. The analog signals go in and out of the
rear panel DB25 connectors J101 and J102 respectively.
The Tape cards have their own D/A and A/D converters, therefore, only digital signals are passed to
and from the DSP board.
Pairs of analog inputs are converted to digital form, for example, input 8 and 7 are combined to form
digital signal DR4 which goes off to the DSP board. DT4 comes back from the DSP board, and is converted
to analog outputs 7 and 8.
NOTE: the digital signals shown below are named as they appear on the Tape card only. The names
are changed at the backplane board before going to the DSP baord. See the next page for details.
This shows the
analog signals
coming in from a
tape deck, and
the digital signals
they become
after A/D
conversion.
For example,
analog signals 8
and 7 come in on
the tape card’s
DB25 input
connector J101
and are
converted to
become digital
signal DR4. This
then goes to the
DSP board for
processing.
This shows the
digital signals
from the DSP
board, and the
analog output
signals they
become after
D/A conversion.
For example,
digital signal DT4
on the Tape card
comes from the
DSP board. This is
converted, and
becomes analog
signal 8 and
analog signal 7.
These appear on
the DB25 output
connector J102
for recording.