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NXR-800H
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3-4. Harmonic fi lter circuit
The harmonic filter circuit uses a three-stage “pi” type
Chebyshev type LPF.
This circuit removes harmonics from the transmitter out-
put and sends the fi ltered signal to the antenna connector
(CN22).
3-5. APC circuit
The APC circuit stabilizes the transmitter power so that
the output power specifi ed by the Control Voltage from the
MPU is obtained. It consists of a Forward/Refl ect power
detector circuit and Differential amplifi ers (IC2 and IC5).
It compares the voltage detected by the Forward/Refl ect
power detector circuit (voltage detected by the Forward
Power) and the Control Voltage (PWR_CONT) from the
MPU (IC802: X56-312 A/3). It stabilizes the output power
by changing pin 2 (Vgg).
The voltage detected (that detected Reflect Power) by
the Forward/Refl ect power detector circuit is compared to
the Control Voltage (PWR_PRT) from the MPU (IC802: X56-
312 A/3). When a load V.S.W.R. is connected to the An-
tenna Connector and is more than 1.5, it functions so that
the output power gets smaller as the detection voltage (that
detected Refl ect Power) gets larger.
ATT
IC4
Diff. AMP
D10
DET
ATT
D9
DET
Reflect
Foward
IC5
Add. AMP
Diff. AMP
IC2
Diff. AMP
Directional coupler
HPF
Pout
VDD
VGG
Pin
IC10
Power module
+
PWR_PRT
PWR_CONT
Fig. 11 APC circuit /
图 11 APC 电路
CIRCUIT DESCRIPTION /
电路说明
3-4. 谐波滤波器电路
谐波滤波器电路采用三阶“pi”式切比雪夫 LPF。
该电路从发射机输出中消除谐波,并将滤波的信号发送到
天线连接器 (CN22)。
3-5. APC 电路
A P C 电路可稳定发射机功率,从而获得由 M P U 的控制电压
指定的输出功率。它由前向 / 反射功率检测器电路和差分放
大器 (IC2 和 IC5) 组成。
它将前向 / 反射功率检测器电路所检测的电压 ( 由向前
功率检测的电压 ) 和 MPU(IC802: X56-312 A/3) 的控制电压
(PWR_CONT) 进行比较。它通过改变针脚 2(Vgg) 稳定输出功率。
前向 / 反射功率检测器电路所检测的电压 ( 反射功率检测
的电压 ) 与 MPU(IC802: X56-312 A/3) 的控制电压 (PWR_PRT)
进行比较。负载 V.S.W.R. 被连接到天线连接器并且大于 1.5
时,它就会发挥作用,使得输出功率随着检测电压 ( 反射功
率检测的电压 ) 的变大而变小。
Fig. 10 Forward/Refl ect power detector circuit /
图 10 前向 / 反射功率检测器电路
ATT
IC4
Diff. AMP
D10
DET
ATT
D9
DET
Reflect
Foward
Directional coupler
Содержание NXR-800H
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