Kenwood NX-800 8. Signaling Circuit, 9. Compander Circuit

NX-800

CIRCUIT DESCRIPTION

D401

DET

Q401

INV

IC402

AVR

IC403

AVR

IC407

80T SW

Q408

80R SW

IC410

DC/DC

IC404

AVR

Q409

50R SW

Q404

SB SW

Q412

50MC SW

IC401

DET

IC405

DC/DC

50MC

SBC

CN405

RS-232C Driver

IC408

AVR

33A

33A-2

ASIC (Analog)

33M ASIC, DSP I/O

Flash memory

+B +B

80C

80R

80T

TXC

/OVRB

/BINT

RXC

SBC

RXC

150C

50C

50R

Final Amp

Audio Amp, Display Block

PA connector

SB D_Sub 25Pin connector

Internal Option

Display Block

TX circuit

RX circuit

Assist, Tune circuit

VCO, Internal Option,

I/O expander, FM IC

IC409

AVR

Q411

33BU SW

IC506

DET

33BU

15M ASIC, DSP core

SRAM, RTC

CPU Reset

Q416

SW Audio circuit

RX circuit

IC406

AVR

33C TCXO, PLL

IC407

AVR

33GPS Internal Option

F401

5A F501

8. Signaling Circuit

8-1. Encode (QT/DQT/DTMF/MSK/2TONE)

Each signaling data signal of QT, DQT, DTMF and MSK is

generated by the DSP circuit, superposed on a modulation

signal and output from IC510. The modulation balance of the

QT/DQT signal is adjusted by the D/A converter (IC712) and

the resulting signal is routed to the modulation input of the

VCO and VCTCXO (X1). The each deviation of the TX QT,

DQT, DTMF and MSK tone is adjusted by changing the out-

put level of the IC510 and the resulting signal is routed to

VCO and VCXO. The RX DTMF tone is routed to the receive

audio signal system, and is output from the speaker.

8-2. Decode (QT/DQT/DTMF/2TONE/MSK)

The audio signal is removed from the FM detection signal

sent to the DSP circuit and the resulting signal is decoded.

9. Compander Circuit