
NX-220
24
9. Compander Circuit
The term “compander” means compressor and expand-
er. The compander reduces noise by utilizing a compressor
and an expander. The transceiver contains a DSP (IC603) to
perform this operation. The transceiver compander can be
turned on or off using the FPU.
Fig. 7 Power supply circuit /
图 7 电源电路
F1
2.5A
F2
1.0A
VOL/SW
+B
TX-RX unit
Q902
SW
IC902
50V
IC507
5.6V Det
IC506
38M
IC501
33A
IC502
33M
IC503
15M
IC505
33C
IC504
50C
Q501
SB2
IC509
100C
Q505
50T
Q503
50R
Q512
50CS
Ripple
filter
IC8
LCD driver
ASIC
IC610
Final AMP, APC
AFPA
2-pin Jack
DSP, FLASH, SRAM
DSP
PLL, TCXO
ASSIST
TX circuit
RX circuit
PLL, fin
VCO
AF circuit
AF circuit, DAC
SQL circuit
LED
/PSW
/BINT
Display unit
CN2
CN5
CIRCUIT DESCRIPTION /
电路说明
9. 压扩器电路
“compander”一词表示压缩器和扩展器。压扩器利用压缩
器和扩展器减低噪音。手持对讲机包含 D S P ( I C603),用以执
行此操作。可用 FPU 开启或关闭手持对讲机的压扩器。
Assist Circuit
(B540-11-042E)