Kenwood TK-3148 Service Manual page 16

TK-3148
6. Control Circuit
The control circuit consists of microprocessor (IC309) and
its peripheral circuits. It controls the TX-RX unit and transfers
data to and from the display unit. IC309 mainly performs the
following;
1) Switching between transmission and reception by 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 decode data input.
6) Transmitting tone and encode data.
6-1. Memory circuit
Memory circuit consists of the CPU (IC309) and a flash
memory (IC308), a flash memory has a capacity of 4M bits
that contains the transceiver control program for the CPU and
data such as transceiver channels and operating features.
This program can be easily written from an external devices.
Data. such as operating status, are programmed into the
EEPROM (IC310).
● Flash Memory
Note : The flash memory stores the data containing the FPU
(KPG-74D CPS) program, Security Number (MPT Serial
Number) and firmware program (User mode, Test mode,
Tuning mode, etc.).
This data must be reinstalled when replacing the flash memory.
● EEPROM
Note : The EEPROM stores tuning data (Deviation, Squelch,
etc.). Realign the transceiver after replacing the EEPROM.
6-2. Low battery warning
The battery voltage is monitored by the microprocessor
(IC309). When the battery voltage falls below the voltage set
by the Low Battery Warning adjustment, the red LED flashes
to notify the operator that it is time to replace the battery. If
the battery voltage falls even more (approx. 6.1V), a beep
sounds and transmission is stopped.
Low battery warning
The red LED flashes during
transmission
The red LED flashes and
continuous beep sounds
while PTT pressed
16
CIRCUIT DESCRIPTION /
IC309
CPU
FLASH
IC308
Fig. 10 Memory circuit / 图 10 存储器电路
Battery condition
The battery voltage is low but
the transceiver is still usable.
The battery voltage is low and
the transceiver is not usable
to make calls.
电路说明
6．控制电路
控制电路由微处理器 （IC309） 和其外围电路组成。 微处理器
控制TX-RX单元和发送到显示单元的数据以及从显示单元发送
的数据。IC309 主要执行下述功能∶
1) 通过 PTT 信号输出在发射和接收之间转换。
2) 从存储器电路读取系统，组，频率和编程数据。
3) 向 PLL 发送频率编程数据。
4) 通过来自于静噪电路的直流电压控制静噪的开启 / 关闭。
5) 通过解码数据输入控制音频静音电路。
6) 发送音频和编码数据。
6-1．存储器电路
记忆电路由 CPU (IC309) 和一块闪存（IC308）组成。闪存容
量 4MB， 载有 CPU 所需的收发机控制程序以及收发机信道、 功
能设置等数据。
可以方便地使用外部设备写这个程序。 工作状态等数据编写
在 EEPROM (IC310)中。
闪存
●
注释∶闪存保存的数据包括 FPU（KPG-74D CPS）程序，安全码
（MPT序列号） 和固件编程 （用户模式， 测试模式， 调谐模式等） 。
当更换闪存时，必须重新安装数据。
EEPROM
●
注释∶EEPROM 保存调谐数据（频偏，静噪） 。
更换 EEPROM 后重新调校手持机。
IC310
EEPROM
6-2．电池低压告警
通过微处理器 （IC309） 监视电池电压。 当电池的电压低于通
过电池低压告警调整设定的电压时，红色指示灯闪烁以提示操
作者更换电池。如果电池的电压继续降低（大约 6.1V） ，则发出
beep 音并停止发送。
电池低压告警
发射过程中红色指示灯闪烁。
当按下 PTT 键时红色指示灯闪 电池电压降低不能使用手持
烁并且手持机发出连续 beep 音。 机发出呼叫。
电池状态
电池电压降低但仍可使用手
持机。