Kenwood NX-800 Service Manual

Also see for NEXEDGE NX-800 series: Brochure Function reference Instruction manual Instruction manual Specifications

NX-800325-4. Local Switch (D101, D205)The connection destination of the signal output fromthe buffer amplifier (Q10) is changed with the diode switch(D101) that is controlled by the transmission power supply,80T, and the diode switch (D205) that is controlled by thereceive power supply, 50R. If the 80T logic is high, it is con-nected to a send-side pre-drive (Q101). If the 80T logic islow, it is connected to a local amplifi er (Q208).LoopFilterBUFFAMPBUFFAMPLPFRippleFilterVCO150CVCTCXOPLLIC3 Q9Q5,Q6D3,D4D7~D12,D14BUFFAMPQ10Q3SDO1SCK1/PCS RFX119.2MHzT/RSWD101,D20550C50Cto TX stage80T50Rto Local AmplifierIC5Q1IC4CVVCO MODASSISTFig. 7 / 图 76. Control CircuitThe control circuit consists of MCU (IC510) and its pe-ripheral circuits. IC510 mainly performs the following;1) Switching between transmission and reception by PTTsignal input.2) Reading system, zone, frequency, and program datafrom the memory circuit.3) Sending frequency program data to the PLL.4) Controlling squelch on/off by the DC voltage from thesquelch circuit.5) Controlling the audio mute circuit by decode data input.6-1. MCUThe MCU (IC510) is 32bit RISC processor, equipped withperipheral function and ADC/DAC.This MCU operates at 18.432MHz clock and 3.3V /1.5VDC. Controls the flash memory, SRAM, DSP, the receivecircuit, the transmitter circuit, the control circuit, and the dis-play circuit and transfers data to or from an external device.CIRCUIT DESCRIPTION / 电路说明5-4. 本地开关 (D101、D205)缓冲放大器 ( Q10) 输出信号的连接目标由二极管开关(D101)( 由发射电源 80T 控制 ) 和二极管开关 (D205)( 由接收电源 50R 控制 ) 进行改变。如果 80T 逻辑高，则它被连接到发送侧预驱动 ( Q101)。如果 80T 逻辑低，则它被连接到接收侧混频器 (Q208)。6. 控制电路控制电路由 MCU(IC510) 和外围电路组成。IC510 主要有以下功能：1) 由输入的 PTT 信号切换发射和接收。2) 从存储电路读取系统、区域、频率和编程数据。3) 将频率数据发送到 PLL。4) 由静噪电路的 DC 电压控制静噪的开 / 关。5) 由输入的解码数据控制音频静音电路。6-1. MCUM C U ( I C510) 是一个 32 位 R I S C 处理器，具备外围功能和ADC/DAC。该 MCU 以 18.432MHz 时钟和 3.3V/1.5V DC 运行。它控制闪存、SRAM、DSP、接收电路、发射机电路、控制电路以及显示电路，并与外部设备双向传输数据。