Signaling Circuit; Encode (Qt/Dqt/Ltr/Dtmf/2-Tone/Msk); Decode (Qt/Dqt/Ltr/Dtmf/2-Tone/Msk); Compander Circuit - Kenwood NX-210 Service Manual

F201
2.5A
IC204
/SAVE
AVR
Q206
/5TC
50T SW
Q205
5RC
50R SW
IC207
SBC
AVR IC
Q201
SB2 SW
IC211
DC/DC
IC205
AVR IC
IC105 (X53)
DC/DC
IC818
5UC
AVR IC
IC210
Q208
AVR IC
31BU
IC206
IC203
DC/DC
AVR
IC209 IC202
Detect DC/DC
IC201
AVR
SB1
Q203
Lvl Conv
VOL SW
Q207 Q204
AND Lvl Conv
D209 D212
SBC
OR OR
Fig. 8 Power supply circuit
CIRCUIT DESCRIPTION

8. Signaling Circuit

TX-RX unit (X57)

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

+B RF Final AMP
APC
50C
and MSK is generated by the DSP circuit, superposed on
VCO
a modulation signal and output from IC308. The modula-
50T
TX circuit
tion balance of the QT/DQT/LTR signal is adjusted by the
D/A converter (IC801) and the resulting signal is routed to
50R
RX circuit the modulation input of the VCO and VCXO (X501). Each
deviation of the TX QT, DQT, LTR, DTMF, 2-tone and MSK
33C tone is adjusted by changing the output level of IC308 and
PLL, VCTCXO
the resulting signal is routed to the VCO and VCXO. The RX
DTMF tone is routed to the receive audio signal system, and
Back Light
SB2
Key Light
is output from the speaker.
TX/Busy LED
150C
Assist, Tune

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

5A
Option
signal sent to the DSP circuit and the resulting signal is de-
–10V
coded.
LCD Bias

9. Compander Circuit

50U
Universal
er. The compander reduces noise by utilizing a compressor
31BU
SRAM, RTC
and an expander. The transceiver contains a DSP (IC302) to
perform this operation. The transceiver compander can be
turned on or off using the FPU.
33M ASIC, DSP I/O,
Flash, LCD DRV
15M
ASIC, DSP core
33A ASIC Analog,
Audio
/PSW
/BINT
IC308
ASIC
Each signaling data signal of QT, DQT, LTR, DTMF, 2-tone
The audio signal is removed from the FM detection
The term "compander" means compressor and expand-
NX-210
17