摘 要 目前国内功率测试的仪器，大多是台式机，其价格昂贵、接口复杂、体积大、笨重，不便于携带进行外场测试；而手持设备通常功能简单，不具有台式功率分析仪的数据分析能力，同时不利于组建复杂的测试系统。从而对于便于携带同时又具有分析能力且易于组建复杂测试系统的功率测试仪器需求比较旺盛。 通过对市场的调研和需求分析，以便携式微波测试仪器的课题研发为依托，以有效值功率测量为切入点，提出设计一款价格便宜、体积小、重量轻、便于携带、易于组建复杂测试系统的基于USB总线的射频微波功率计。对此功率计所需的功能展开分析，按照虚拟仪器的设计思想，提出功率计系统的总体设计方案。整个系统由两部分组成，上位机应用软件系统和USB设备系统。USB设备系统主要负责射频信号的处理，信号采集以及与上位机通信等功能。应用软件系统主要完成与功率计USB设备的通信，数据的分析处理和显示以及功率的校准。 本论文主要针对USB设备系统展开研究和设计，USB设备系统由两部分组成，硬件电路和控制设备进行数据采集和数据传输的固件程序。对于射频信号的输入使用50 标准SMA头作为接口，采用可以检测有效值功率的对数检波器实现有效值功率检测，以ATMEL公司的AVR单片机作为系统的核心控制芯片，实现数据的采集以及与上位机应用软件系统的USB总线通信。使用Protel99SE对系统的硬件电路原理图和PCB板进行设计和制作。固件程序是在ATMEL公司所编写的开发环境AVR Studio4.18中使用C语言进行开发的，C代码的编译采用WinAVR进行编译，使用微控电子开发的JTAGICE烧写器给芯片烧写可执行文件，通过串口调试助手和总线监测软件进行软件系统的调试。通过实际的设计和制作，并使用射频信号源和精密万用表等测量仪器对检波部分做测量，测试结果基本满足检波功能要求；使用BusHound总线监测软件对USB总线传输进行监测，其结果满足传输要求。最后此硬件设备基本实现了该硬件系统的设计方案。 关 键 词：射频功率计；有效值功率；USB总线；对数检波；功率测量 研究类型：应用研究型

ABSTRACT At present, the domestic power measurement instruments are mostly desktop with complex interfaces and big appearance, which are expensive and inconvenient to carry for field test. While handheld devices usually have a simple function, does not have data analysis capability of the desktop power analyzer, and is adverse to form a complex measurement system. Thus the power measurement instruments with portability and analysis ability and easy to form complex testing system are demanded more briskly. Through market research and requirements analysis, relying on the subject of research and development of portable microwave test equipment, as the breakthrough point of RMS power measurements , microwave power meters based on USB bus is put forward, which are cheap, small size, light appearance, easy to carry and set up a complex test system. The function of the power meter is analyzed, the general design of power meter system is proposed according to the design method of virtual instrument. The entire system consists of two parts, one is the host computer software systems, and the other is hardware systems of the power meter device. The hardware system is mainly responsible for the RF signal processing, signal acquisition and host computer communication. Software system mainly completes the analysis of the data processing and displaying as well as the calibration of the power and communication with the power meter hardware. This paper is focused on the hardware system to expand the research and design .The hardware system consists of two parts, one is hardware circuits, the other is system software for controlling equipment for data acquisition and data transmission. The 50 standard SMA head is used as the input interface for the radio frequency signal, logarithmic detector with detection of RMS power can be used to detect RMS power. The AVR MCU of ATMEL Company as the main controller of the system, with which the data acquisition and communication with host by USB bus is realized. The Protel99SE are used to design hardware circuit schematics and PCB production. The software system was developed using C language to write in the AVR Studio4.18 of the ATMEL AVR development environment, and the WinAVR compiler is used to complie program, the implementation the programming on the core chip is used JTAGICE programmer by micro-control electronics development. The software system is debugged by serial port debug assistant and bus monitoring software .The RF signal source and precision multimeter are used to measurement the detection part , and test results are meet the basic requirements of detecting function; The BusHound bus monitoring software is used to monitor USB bus, and the results satisfy the transmission requirements. Finally, the hardware system meets the basic demand of hardware system design. Keywords：Radio frequency power meter root meam square power USB bus Logarithmic detector power measurement Thesis ： Application Research