Kenwood NXR-800H Service Manual

NXR-800H19The D/A converters (IC701 and IC802) converts the AGCsetting (D_PC) of the driver circuit and control voltage value(PWR_CONT, PWR_PRT) of the Final Unit (X45-386 A/5).The A/D converter (IC803) converts the transmitter unit(X56-312 A/3) temperature, VCO & VCXO control voltage(CVT, CVT-REF and CVT-MOD), Final Unit (X45-386 A/5) PAcurrent (PA_CURR), fan current (FAN_CURR), detection volt-age (FWD_PWR, RFL_PWR), etc.The shift register (IC703) controls each part of the trans-mitter unit (X56-312 A/3) based on serial data of the ControlUnit (X53-413).3. Final unitThe RF final amplifier unit (X45-386 A/5) amplifies thetransmitter power to a specified level.This unit consists of the following circuits:(1) Transmitter power module(2) High pass filter(3) Forward/Refl ect power detector circuit(4) Antenna switch(5) Harmonic filter circuit(6) APC circuit(7) High temperature detector circuit(8) FAN action control circuit(9) Current detector circuit(10) AVR Circuit(11) Other Circuits3-1. Transmitter power moduleThe power module IC10 uses power module RA30H4047M123 (C) or RA45H4047M131 (C2) to improve its efficiency.The driver output of the transmitter unit passes through anattenuator and enters the power module IC10 pin 1. Powermodule IC10 amplifies the RF power according to the volt-age at the amplification control pin 2 (VGG) and outputs itthrough pin 4 (Pout).3-2. High pass filterThe T type single stage high pass filter prevents the Pow-er Amplifier Module from being broken by static electricity.3-3. Forward/Reflect power detector circuitThe forward / Refl ect power detector circuit consists of aCM coupling type detection circuit formed by a Micro stripline and the differential amplifier IC4.A part of the transmitter power is detected by diodes D9and D10 and is converted into DC voltage.CIRCUIT DESCRIPTION / 电路说明D / A 转换器 ( I C701 和 I C802) 转换驱动电路的 A G C 设置 ( D _ P C ) 和末级单元 ( X45-386 A /5) 的控制电压值 ( P W R _CONT,PWR_PRT)。A/D 转换器 (IC803) 转换发射机单元 (X56-312 A/3) 温度、VCO & VCXO 控制电压 (CVT、CVT-REF 和 CVT-MOD)、末级单元(X45-386 A/5)PA 电流 (PA_CURR)、风扇电流 (FAN_CURR)、检测电压 (FWD_PWR、RFL_PWR) 等。移位寄存器 ( I C703) 根据控制单元 ( X53-413) 的串行数据控制发射机单元 (X56-312 A/3) 的各个部分。3. 末级单元RF 末级放大器单元 (X45-386 A/5) 将发射机功率放大到指定电平。该单元由以下电路组成 :(1) 发射机功率模块(2) 高通滤波器(3) 前向 / 反射功率检测器电路(4) 天线开关(5) 谐波滤波器电路(6)APC 电路(7) 高温检测器电路(8)FAN 动作控制电路(9) 电流检测器电路(10)AVR 电路(11) 其它电路3-1. 发射机功率模块功率模块 IC10 用 RA30H4047M123(C) 或 RA45H4047M131(C2)的功率模块提高其效率。发射机单元的驱动器输出通过衰减器并进入功率模块 IC10 针脚 1。功率模块 IC10 根据放大控制针脚 2(VGG) 的电压放大 RF 功率，将其从针脚 4(Pout) 输出。3-2. 高通滤波器T 型单级高通滤波器可防止功率放大器模块受到静电损坏。3-3. 前向 / 反射功率检测器电路前向 / 反射功率检测器电路由微带线形成的 C M 耦合式检测电路和差分放大器 IC4 组成。发射机功率的一部分被二极管 D9 和 D10 检测并转换为 D C电压。Fig. 9 Transmitter power module / 图 9 发射机功率模块RA30H4047M123 (C)RA45H4047M131 (C2): Pin @ VGG . VDD ; Pout