Similar to other kind of communication systems, the radio frequency modular of RSU in DSRC include many parts such ad antenna, duplexer, low noise amplifier, local oscillator, mixer, filter, modulator, demodulator, and so on. It`s difficult to analyze every part in the system fully, so the emphasis is mainly on the parts designed and implemented for the RSU by myself.
和其它通信系统类似，专用短程通信系统路边单元的射频部分包含天线、双工滤波器、低噪声放大器、混频器、本振、滤波器、调制解调器等多个功能模块，论文中要完整地介绍和分析每一个功能模块是困难的，因此本文主要介绍自己亲自完成的部分。
The invention can reduce the bandwidth demand of a microwave source and an electro-optical modulator to one half to one-tenth at the same time of generating the millimeter-wave subcarrier phase modulation with the same effect, the upward frequency conversion of the millimeter-wave frequency mixer is not needed; only a section of millimeter-wave transmission line is needed between a detector and an antenna to avoid the usage of other high-frequency devices, so the system has simple structure, reliable performances and low cost.
本发明使得在产生同样效果的毫米波副载波相位调制时，对于微波源、电光调制器的带宽需求降至一半到十分之一，且不需要经过毫米波混频器进行上变频；只在探测器与天线之间需要一段毫米波传输线，避免使用其他高频器件，使系统结构简单、性能可靠、成本低廉。
For system circuitry design section, millimeter wave multi-mode antenna, W-band single-end balanced diode mixer and cavity-stabilized IMPATT Diode Oscillator, were introduced. Isolator was also discussed by taking the receivers inverse radiation noise in to account when absolute calibration is necessary. Balanced mean square-law detector, having relative high stability with a feedback loop, was derived from the common Schottky barrier diode detector. After that, calculation principles and method of IF gain was presented, the 1st and 2nd IF circuitries were implemented with MMIC amplifiers. At last, Difference amplifier, auto gain control model, data acquisition system, USB interface and temperature holding circuitry were discussed briefly.
在系统电路设计方面，讨论了毫米波多模喇叭天线、单端平衡阻性二极管混频器、加稳频腔的IMPATT振荡器；通过分析逆向辐射噪声对绝对定标的影响，讨论了增加隔离器的意义；在肖特基平方律检波二极管的基础上提出了反馈平衡平方律检波器；讨论了中频放大器增益计算原则和方法，设计了第一中频放大电路和主中频放大电路；根据系统灵敏度的要求设计了差分放大电路、增益控制电路、采样电路、USB接口电路、恒温电路等。
For system circuitry design section, millimeter wave multi-mode antenna, W-band single-end balanced diode mixer and cavity-stabilized IMPATT Diode Oscillator, were introduced.
在系统电路设计方面，讨论了毫米波多模喇叭天线、单端平衡阻性二极管混频器、加稳频腔的IMPATT振荡器；
An experimental method to obtain the monopole antenna parameters is given. Measured at 4.2 K using a calibrated monochromatic signal source, the SSB conversion efficiency of the mixer de-signed according to this method is 0.62.
给出了确定单极子天线参数的实验方法，据此设计的混频器，在4.2K上用校正的单色信号源测得了其单边带变频效率为0.62。