【作者】 何松柏；

【导师】 虞厥邦；

【作者基本信息】 电子科技大学 ， 电路与系统， 2003， 博士

【摘要】 随着无线通信技术的广泛应用，为了满足无线产品的高性能和低成本要求，对包括无线收发信机在内的技术研究开发就具有重大的现实意义。本文对作者参与开发的几种专用无线通信系统中的收发信机和其中的若干关键设计技术进行了分析研究。作者的主要贡献和创新如下：1. 在采用QPSK调制的无线通信系统中，由功率放大器（PA）非线性失真引起的交调效应会产生同频及邻频信道干扰而使误比特率（BER）增加。有鉴及此，我们针对功放PA进行了统计谱分析，导出了在功放非线性失真起主要作用的三阶交调系数（IM3）与系统误码率的关系并经计算仿真验证为正确。导出的计算式有助于QPSK通信系统中高性能功率放大器的设计。2. 在基于IS－95协议的CDMA系统基站中，功率放大器通常需采用前馈线性化技术以改善其线性度。文中推导出该前馈线性化功放（FFLPA）的设计公式并进行了计算机仿真以检验其正确性。线性前馈技术中采用的载波及交调对消环路中，信号幅度和相位的不完善对消对于三阶交调IM3的影响在这些公式中均作了定量评估。根据这些公式设计了该功放并用于原型基站中，其性能指标的测试结果令人满意。3. 在数字微波QPSK通信系统中，一个基于锁相环的本振信号源中的相位噪声，有可能是使系统性能恶化的重要因素之一。为了减小相噪对系统性能的影响，导出了此类信号源的设计判据，据此可基于折衷考虑选取环路带宽，以便同时获得较低的误码率，以及低的寄生输出和较快的频率跳变速度。4. 研究了一个混沌跳频通信系统，重点是采用数字直接频率合成与锁相环技术相结合方式构成的跳频频率合成器开发，此外，建议了一种基于二阶混沌映射的扩频码，以代替过去报导过的Logistic混沌码。5. 对各种无线通信系统中使用的收发信机设计作了简要陈述，此外，还介绍了作者参与开发的几种专用无线通信系统中的收发信机，其中包括CDMA基站、宽带无线接入系统、智能交管系统中的专用短程通信系统，以及混沌跳频通信<WP=6>系统中使用的收发信机等。更多还原

【Abstract】 As wireless communication products become an everyday part of people’s lives, the need for higher performance at lower costs becomes even more important. Overcoming the challenges involved in the design of radio frequency(RF) transceivers can help meet this need. This dissertation presented the prototype wideband RF transceivers for Ad.Hoc communication systems developed by the author and design issues for achieving both high performance and low cost. The main contributions of the dissertation are as following:1. In a wireless communication system using QPSK modulation, it is well known the intermodula caused by the nolinearity of PA (power amplifier) will generate adjacent channel and co-channel interference thereby increasing the BER (bit rate error). This fact motivate us to conduct a statistic spectral analysis of the PA. A relation of the third order intermodulation (IM3), playing a key role for the nonlinear distortion generated by PA, vs the BER is derived and justified by computer simulations. The result will be helpful in designing a high perfomance PA in QPSK communications systems.2. In a CDMA IS-95 base station, the power amplifier usually employs feed-forward linearization technique, such as carrier cancellation and intermodulation cancellation, to improve its linearity. Design formulas for the feed-forward linearized power amplifier (FFLPA) are derived and justified by computer simulations. The influence of the imperfect amplitude/phase carrier and intermodulation cancellation upon the IM3 is evaluated quantitatively in these formulas, A prototype FFLPA hardware was designed based on these formulas, then integrated into the base station. The specifications of the station as well as the performance of the FFLPA were tested and measured respectively. Measurement results are proved to be satisfactory.3. For a digital microwave QPSK communication system, the phase noise existing in a PLL based local signal source could be one of the major factors responsible for the degradation of system performance. Design criteria for such signal source are derived, upon which one can choose the PLL loop bandwidth by trade-off considerations, to get a relatively low BER, simultaneously obtain low spurious output and fast frequency hopping as well.<WP=8>4. An chaotic FH wireless communication system is studied with the emphasis on a DDS-PLL hybrid frequency synthesizer design as well as a new spread spectrum sequence based on a second order discrete chaotic mapping.5. A brief survey on tranceiver design for wireless communications is addressed, also given are prototype tranceivers for Ad. Hoc communication systems developed by the author, including those used in CDMA base station, wideband wireless access system, chaotic FH system and DSRC/ITS.更多还原