Kenwood NXR-700H Service Manual page 18

NXR-700H
the VCXO (X301) control voltage and modulating signal.
IC301 is a reference voltage generator (A/2) in modulat-
ing level adjusting circuit and non-inverting amplifi cation of
modulating signal with a cutoff signal of approximately 9kHz
(B/2).
2-8. AVR circuit
IC104, IC603, IC704, IC705, IC706, IC807, IC808 and
IC809 are AVR ICs.
Each circuit contains its own power regulator IC to main-
tain isolation between circuits.
2-9. Other circuits
In addition, IC702 is an EEPROM. The transmitter ad-
justment data adjusted for each unit is written into the
EEPROM. If the unit is installed in another set, it is not nec-
essary to adjust it again from the beginning, but only fi ne-
tuning is necessary for each unit.
The temperature sensor (IC804) monitors the tempera-
ture of the transmitter unit (X56-311 A/3).
18
CIRCUIT DESCRIPTION /
5V #2
Mod
signal
Control
4 1
unit
CN804
IC304
10
Fig. 7 Modulation level adjustment circuit / 图 7 调制电平调整电路
CN801
VBATT
+13.2V
Fig. 8 AVR circuit / 图 8 AVR 电路
电路说明
I C301 是调制电平调整电路和调制信号的非反相放大中的
基准电压发生器 (A/2)，截止信号约为 9kHz(B/2)。
TX Mod 19.2MHz
PLL CP
5V #2
5V #2
3
5V #2
IC305
IC305
(B/2)
(A/2)
2
5V #2
IC301
(B/2)
IC308 (B/2)
2-8. AVR 电路
I C104、I C603、I C704、I C705、I C706、I C807、I C808 和
IC809 是 AVR IC。
每个电路都含有各自的功率调节器 I C，以保持电路之间的
隔离状态。
8V #2
IC704
8V
IC809
9V
Ripple
IC104
filter
8V #1
IC808
SW
IC807
IC706
IC705
2-9. 其它电路
此外，I C702 是一个 E E P R O M。对各单元调整的发射机调整
数据被写入 E E P R O M。如果将单元安装在另一装置中，不需要
从头开始重新调整，而只需要对各单元进行微调。
温度传感器 ( I C804) 监测发射机单元 ( X56-311 A /3) 的温
度。
TX Mod 19.2MHz
PLL circuit
VCXO_CV
TX main
PLL circuit
VCO_MOD
8V #2
CN807
OCXO
9V'
8V #1
8V #1'
5V #1
5V #2
5V #3
IC603 3.3V