Kenwood TM-D700A Service Manual page 12

TM-D700A/E
12
CIRCUIT DESCRIPTION
5-3.Serial control
The CPU (IC604) controls the panel unit (X54-329 unit)
through a synchronous serial communication. The CPU
(IC604) controls the TNC CPU (IC3: X52-331 unit) through
9600bps serial communication. In APRS mode, settings and
transmission data are sent from the CPU (IC604) to the TNC
and received packet data is sent from the TNC to the CPU
(1C604). In the packet transmission mode, a personal
computer is connected with the CPU (IC604)through the RS-
232C driver (IC600). The data from the personal computer is
received by the CPU (IC604) and transferred to the TNC
CPU(IC3). The received packet data is sent from the TNC
CPU(IC3) to the main CPU(IC604), which transfers the raw
data to the personal computer. In the personal computer
control mode, the CPU(IC604) receives and processes data
from the personal computer and sends the processed data
back to the personal computer.
GPS
TNC
r s
X62-331
COM
[Personal computer] -«———+] CPU
IC604
DISPLAY
X54-329
Fig.13 Structure of non-synchronized serial
communication
5-4.Narrow/Wide switching circuit (TM-D700E only)
The receiver band width can be switched between narrow
and wide by selecting IF ceramic filters, CF100 (narrow) and
CF101 (wide) on the A band with a switching circuit(Q100,
Q101, D100, D101). On the B band, the receiver band width
can be also switched between narrow and wide by selecting IF
ceramic filter CF400 (narrow) and CF401 (wide) with a
switching circuit (Q400, Q401, D400, D401).
The transmitter deviation can be switched between narrow
and wide by setting the electronic variable resistor (IC804) on
the deviation adjustment point. It is controlled from the CPU
(IC604).
IC100
TA31136FN
i |
CF WIDE
CF101
(ow CF NARROW (o0")
CF100
IC400
TA31136FN
J |
CF WIDE
CF401
(+) CF NARROW
CF400
D400
Fig.14 Narrow/Wide Switching circuit