【作者】 孙文功；

【导师】 王华奎；

【作者基本信息】 太原理工大学 ， 电路与系统， 2002， 硕士

【摘要】 随着有线电视网络的发展，手持式场强仪的需求量也越来越大。本文详细介绍和分析了模拟中频和数字中频两种场强仪实现方案，对于同类产品的研究有很大的参考价值。 模拟中频方案将待测信号变频到固定中频上，对信号进行解调、对数放大、检波后，输出反映待测信号强度的直流信号，通过A/D转换送入单片机进行软件处理。本文详细叙述了实现模拟中频方案的硬件电路和软件系统，说明了场强仪中各种电路特性对测量精度的影响以及对场强仪进行数据标定的方法。 数字中频方案将中频信号直接通过A/D转换后送入DSP芯片进行DFT变换，最后得到待测信号频谱的采样序列。本文介绍了该方案的原理，对该方案的硬件和软件进行了分析设计，并且在TMSC5402DSK上对该方案进行了仿真实验。理论和实验证明了数字中频方案在频率分辨力和测量精度上都超过了模拟中频方案。更多还原

【Abstract】 Followed with the fast development of cable TV, the requirement of handy field strength meter become more and more. Two projects to produce it are described in detail in this paper, which are analog intermediate frequency project and digital intermediate frequency.In the analog intermediate frequency project, the signal to be measured is converted to be a fixed intermediate frequency signal, which then is demodulated, logarithm amplified and detected to be a DC signal that can reflect the original signal strength. After passing the A/D Converter, it will be processed by Microcontroller in software. This paper describes the hardware and software to implement the project in detail and explains how the circuit characteristics influence the measurement error and how to processing the data .In the digital intermediate frequency project, the intermediate frequency signal is converted to digital signal directly into the DSP chip, then it is be processed by DFT. In this paper, the principle of the project is introduced, the hardware and software of it are analyzed and designed and the project is evaluated in the TMS320C5402DSK. It is proved that the digital project is better in the frequency resolution and amplitude accuracy .更多还原