TK-3201
9
Note:
The transceiver checks the battery voltage during reception
even when, in the FPU, the Battery Warning status function
is set to “On TX” (default setting).
However, the LED does not blink during reception. During
transmission, the LED blinks to generate the warning tone
of a low battery voltage.
(2) The transceiver immediately stops transmission when
the battery voltage falls below the voltage (2) shown in
the table. A message tone beeps while the PTT switch
is released.
4) Encode Signalling
(1) QT/DQT
QT,DQT data of the QTTCXO Line is output from pin 28 of
the CPU. The signal passes through a low-pass CR filter
and goes to the TCXO(X1).
The QT,DQT data of the QTVCO Line is output from pin 24
of the CPU. The signal passes through a low pass CR filter,
mixes with the audio signal, and goes to the VCO
modulation input. TX deviation is adjusted by the CPU.
5. Power Supply
There are four 5V power supplies 5M,5C,5R, and 5T. 5M
for microprocessor is always output while the power is on.
5M is always output, but turns off when the power is turned
off to prevent malfunction of the microprocessor.
5C is a common 5V and is output when SAVE is not set to
OFF.
5R is 5V for reception and output during reception.
5T is 5V for transmission and output during transmission.
6. Control Circuit
The control circuit consists of a microprocessor (IC405) and
its peripheral circuits. It controls the TX-RX unit. IC405 mainly
performs the following:
(1) Switching between transmission and reception by the
PTT signal input.
(2) Reading system, group, frequency, and program data
from the memory circuit.
(3) Sending frequency program data to the PLL.
(4) Controlling squelch on/off by the DC voltage from the
squelch circuit.
(5) Controlling the audio mute circuit by the decode data
input.
(6) Transmitting tone and encode data.
1) Memory Circuit
Memory circuit consists of the CPU (IC405) and an EEPROM
(IC406). An EEPROM has a
capacity of 64k bits that contains
the transceiver control program for the CPU and data such
as transceiver channels and operating features.
2) Low Battery Warning
The battery voltage is checked using by the microprocessor.
The transceiver generates a warning tone when it falls below
the warning voltage shown in the table.
(1) The red LED blinks when the battery voltage falls below
the voltage (1) shown in the table during transmission.
IC405
CPU
IC406
EEPROM
Fig. 7 Memory circuit
SB
R404
R406
88
IC405
CPU
Fig. 8 Low battery warning
CIRCUIT DESCRIPTION
Ni-Cd Battery
Ni-MH Battery
(1)
6.2[V]
6.2[V]
(2)
5.9[V]
5.9[V]
Channel selector
CPU
IC405
EN4
EN5
EN3
EN2
EN1
47
46
48
49
50
PTT
SW
27
74
75
SW1
SW2
MONITOR
PTT
CALL
Fig. 9 Control system
7. Control System
Keys and channel selector circuit.
The signal from keys and channel selector input to
microprocessor directly as shown in fig. 9.
