基于C6711处理器cdma2000 1X系统前向信道信号的处理

在cdma20001x前向信道中,要对一段信号进行传送,一般选用QPSK调制,因为QPSK调制比QAM更适合噪音环境。采用TI6000系列的TMS320C6711芯片处理前向信道信号,可以对复杂性和实时性较高的信号做采集、量化、编码、调制等实时处理,主要功能通过软件编程实现,从而使系统具有结构灵活、可靠性高、可扩展等优点。     

MULTICARRIER DS—CDMA WITH ADAPTIVE MODULATION AND POWER ALLOCATION

Adaptive modulation and power allocation is introduced into the multicarrier DSCDMA system to improve the system performance and bandwidth efficiency.First,the system design appropriate for adaptive modulation and power allocation is given,then the algorithm of adaptive modulation and power allocation is applied.Simulation results demonstrate great performance improvement compared with the fixed modulated one.     

DMT系统中一种易于实现的时域均衡器

总结了DMT系统中时域均衡器(TEQ)的主要设计方法，指出最大缩短信噪比(MSSNR)TEQ的最优设计方法很难实时实现。提出了一种MSSNR TEQ的次优设计方法，它首先估计出目标抽样窗的最优延迟，然后用分步求解法求出TEQ的抽头系数。和最优方法相比，次优方法的计算量大幅度减少，可实时实现，而其缩短信噪比的损失很小。仿真实验验证了次优方法的有效性。     

一种实现非等带宽多载波调制的新方法

传统的多载波调制都是采用对传输信道进行等带宽划分的方式。为了更好地适应信道传输特性，一个很有应用前景的发展方向是采用非等带宽划分信道的多载波调制方式。本文提出了一种利用正交小波包变换实现的非等带宽划分信道的多载波调制方法。理论分析和实验结果表明，这种方法对于提高信道的传输性能有很大的潜力。     

Modulation and Equalisation Considerations for High Performance Radio LANs

The European Telecommunications Standards Institute (ETSI) has recently defined a European standard for a high performance radio LAN (known as HIPERLAN). To operate as wired LAN replacements, these systems will operate at 5.2 GHz and support instantaneous bit rates of just under 24 Mb/s. To counteract the time dispersive nature of the indoor radio channel, the use of adaptive equalisation is suggested. In this paper a number of possible modulation and equalisation techniques are presented and, in particular, the Bit Error Rate (BER) performance of quasi-coherent GMSK combined with Decision Feedback Equalisation is explored through computer simulation. The trade off between symbol spaced and fractionally spaced equalisation is considered together with the importance of feedfoward and feedback synchronisation to the channel's power delay profile. The paper also includes a comparison of the RLS and LMS based training algorithms and compares the modem developed under the ESPRIT III LAURA project with that specified in HIPERLAN.The application of dual antenna diversity is investigated and its impact on the number of received error free data packets obtained as a function of signal leval and rms delay spread. The use of such diversity is shown to greatly improve the BER performance of a HIPERLAN modem. The problem of frequency offset is considered and modifications are proposed to the HIPERLAN frame structure to improve the receiver's tolerance to such errors. Important practical issues such as frame and symbol synchronisation, frequency offset correction and hardware implementation are discussed from both the LAURA and HIPERLAN viewpoint.     

有机极化聚合物材料及电光调制器件

有机极化聚合物材料是一类新型的功能高分子材料，在光电子及集成光学方面具有诱人的应用前景，其电光调制器件已接近实用化，本文综述了有机极化聚合物材料，极化聚合物体系及电光调制器件的研究进展，并指出它们存在的问题和发展方向。     

多进制数字调相系统分析与设计方法的探讨

对数字通信中MPSK系统的调制与解调问题进行了较为的分析，并以8PSK和循环码16PSK系统为例，阐述其调制器电路的逻辑设计方法。在此基础上给出了8PSK系统调制与解调的一种方案，讨论了循环码和自然二进制码16PSK系统的调制器的具体设计过程，该设计方法可应用于一般MPSK系统的逻辑设计。     

一种语音混沌保密通信方案的研究与硬件实现

在硬件实验研究的基础上，建立一种环形蔡氏电路，提出用环蔡氏电路实现语音混沌保密通信的一种闭环逆系统方案，其特点是利用环形蔡氏电路的单向耦合原理，通过反馈的方法形成一个包括有用信号在内的极联闭合环路，从而实现改善端与接收端之间混沌系统的严格同步而不受有用信息调制的影响。理论分析与硬件实验结果证明，该方案同现有的其它混沌通信方案相比较，具有非线性失真小、保真度高的优点，完全能够满足传送语音信号的要求。     

宽带线性调频信号产主技术研究

本文介绍了采用数字基带产生结合倍频链扩展带宽的方法设计与实现了大带宽线性调频信号产生系统。详细分析研究了实现系统的三项关键技术，给出并分析了相应环节的输出信号。对系统进行了预失真补偿处理，成功实现了ＶＨＦ／ＵＨＦ波段、带宽达３００ＭＨｚ线性调频信号的产生。经脉冲压缩处理，主瓣旁瓣比（ＰＳ１Ｒ）在－３７ｄＢ以下。     

A novel compact circuit for 4-PAM energy-efficient high speed interconnect data transmission and reception

Transmission of signals, whether on-chip or off-chip, places severe constraints on timing and extracts a large price in energy. New silicon device technologies, such as back-plane CMOS, provide a programmable and adaptable threshold voltage as an additional tool that can be used for low power design. We show that one particularly desirable use of this freedom is energy-efficient high-speed transmission across long interconnects using multi-valued encoding. Our multi-valued CMOS circuits take advantage of the threshold voltage control of the transistors, by using the signal-voltage-to-threshold-voltage span, in order to make area-efficient implementations of 4-PAM (pulse amplitude modulation) transceivers operating at high speed. In a comparison of a variety of published technologies, for signal transmission with interconnects of 10-15 mm length, we show up to 50% improvement in energy for on-chip signal transmission over binary encoding together with higher limits for operating speeds without a penalty in circuit noise margin.