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TK-5710

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)

/5710H

(

)

written by the FPU (KPG-95D), and firmware program (User
mode, Test mode, Tuning mode, etc.). This data must be
rewritten when replacing the flash memory.

■

EEPROM

Note :

The EEPROM (IC701) stores tuning data (Deviation,

Squelch, etc.).
Realign the transceiver after replacing the EEPROM.

■

Real-time clock

The clock function is based on real-time clock IC (IC700).

When the power supply is off, it is backed up by an internal
secondary lithium battery.

6-2. Temperature Detection Circuit

T h e t e m p e r a t u r e d e t e c t i o n c i r c u i t d e t e c t s t h e

temperature using a temperature IC (IC702) and corrects the
thermal characteristic change of the squelch.

6-3. DSP

The DSP circuit consists of a DSP IC (IC715), a CODEC IC

(IC724) and processes the base band signal. The DSP IC op-
erates on an external clock of 9.216MHz (the same as the
CPU), the I/O section operates at 3.3V and the core section
operates at 1.5V. The DSP IC carries out the following pro-
cesses:
• C4FM encoding
• Analog FM pre-emphasis/de-emphasis
• Vocoder (IMBE) processing between audio codec and

modulation/ demodulation

• CAI processing, such as error correction encoding
• QT/DQT encoding/ decoding
• DTMF encoding/ decoding
• MSK encoding/ decoding
• 2-tone decoding
• Compressor/ expander processing
• Transmit/ receive audio filtering processing

• Microphone amplifier AGC processing
• Audio mute processing
• Modulation level processing

6-4. FPGA

The FPGA IC (IC730) I/O section operates at 3.3V and the

core section operates at 2.5V. The FPGA IC has the following
function.
• Demodulation (C4FM,CQPSK)
• Shift register (8CH)
• Level convert Buffer amplifier(5V

➝

3.3V)(9CH)

• Generates 1.536MHz for the demodulation and CODEC

7. Power Supply Circuit

The voltage is always applied from +B. D719 protects

IC705 (DFF) against overvoltage.

Pulses from power switch are fed to the IC705 clock line

and the CPU (IC703). These clock pulses reverse the output
from High (The transceiver is turned OFF) to Low (The trans-
ceiver is turned ON), but it does not reverse the output from
Low to High. The CPU (IC703) output the pulse to the S2
(SET2) terminal (pin 8) of IC705 to reverse the output from
Low to High.

IGN is connected to the R2 (RESET2) terminal (pin 10) of

IC705 and the CPU (IC703). When the IC705 reset voltage is
increased, the output changes to Low (The transceiver is
turned ON). When IGN voltage is decreased, the CPU (IC703)
output the pulse to the S2 terminal (pin 8) of IC705 to reverse
the output from Low to High after the programmed time ex-
pires (Timed power-off function).

If 24V is supplied to the transceiver by mistake, Q707

turns on, Q710 turns off, the power is forced to be turned off.

This circuit consists of IC706 (8V), IC707 (5V), IC708

(3.3V), IC710 (3.3V), IC711 (2.5V) and IC709 (1.5V).

Fig. 13

Clock diagram

CIRCUIT DESCRIPTION

CPU

EEPROM

FLASH

IC703

IC712