多载波格状编码调制的实现和性能分析

本文综合考虑复杂度、时延和实时性等因素，讨论了格状编码应用在多载波调制系统中的具体实现方案，并在ＡＤＳＬ ＤＭＴ环境下对其性能进行了模拟分析。结果显示，格状编码用于多载波调制系统时仍然能够获得大部分理论编码增益。     

级连码和数据交织技术在数字HDTV中的应用

本文分析采用格状编码调制的自适应均衡技术对ＨＤＴＶ传输系统性能的影响以及ＨＤＴＶ同播传输的干扰环境，给出克服干扰的措施，设计一种适合于ＨＤＴＶ应用的级连格状编码和ＲＳ码方案，并对其进行计算机模拟，模拟结果表明：该方案具有较好的误码性能。     

COFDM数字电视广播系统中使用CSI的维特比译码器

介绍比特交织格状编码调制 ＭＱＡＭ的编译码原理,软判决译码中使用信道状态信息（ＣＳＩ）是ＣＯＦＤＭ在频率选择性衰落和干扰下获得优异性能的关键。研究ＣＯＦＤＭ数字ＴＶ广播系统中使用ＣＳＩ的维特比译码器的一种实现方法。     

8状态32QAM维特比译码器的硬件设计

由于格状编码调制可以在相同的频带利用率下使信号得到２．５５－７．３７ｄＢ的编码增益，所以得到了广泛的应用。鉴于ＴＣＭ的维特比译码器在ＨＤＴＶ系统实现中具有的重要作用，本文开展了对维持比译码器的硬件设计工作。     

第七讲 格状编码调制的维特比译码算法

格状编码调制（ＴＣＭ）可以在相同的频带利用率下，使信号得到２．５５～７．３７ｄＢ的编码增益，在数字通信中得到了广泛的应用，ＴＣＭ的维特比（Ｖｉｔｅｒｂｉ）译码算法是一种最大似然译码方法，它可以充分体现了ＴＣＭ的优点，本文讨论了维特比译码算法的原理，并以４状态卷积码和ＨＤＴＶ地面广播中使用的ＴＣＭ－３２ＱＡＭ为例，介绍了硬判决维持比译码和软判决维特比译码算法的译码过程。     

数字HDTV地面广播传输方法 第七讲 格状编码调制的维特比译码算法

格状编码调制（ＴＣＭ）可以在相同的频带利用率下，使信号得到２．５５～７．３７ｄＢ的编码增益，在数字通信中得到了广泛的应用。ＴＣＭ的维特比（Ｖｉｔｅｒｂｉ）译码算法是一种最大似然译码方法，它可以充分体现ＴＣＭ的优点。本文讨论了维特比译码算法的原理，并以４状态卷积码和ＨＤＴＶ地面广播中使用的ＴＣＭ－３２ＱＡＭ为例，介绍了硬判决维特比译码和软判决维特比译码算法的译码过程。     

HDTV传输中VSB与OFDM调制方案的比较

本文介绍了当前国际上二种主要的全数字高清晰电视传输系统中采用的调制解调方案，即美国的残留边带调制（ＶＳＢ）方案和欧洲的正交频分复用调制（ＯＦＤＭ）方案，并结合格状编码，前向纠错编码，交织及均衡等技术对二种方案进行了计算机仿真，根据仿真结果对其性能特性进行了比较和分析，得到了理想的结果。本文得到国家自然科学重点基金和国家科委“八五”攻关项目的资助。     

可编程DSP调制解调器控制程序设计

可编程ＤＳＰ调制解调器控制程序设计刘丹谱，乐光新近年来，由于格状编码调制（ＴＣＭ）技术的应用，话路调制解调器在传输速率上有了极大的提高，目前符合ＩＴＵＴＶ．３４国际标准的２８．８ｋｂ／ｓ速率话带调制解调器已经开始投入商用。这些高速调制解调器的实现都需...     

TCM信号译码的简化算法

本文从格状编码调制技术的基本原理出发，针对差分相干检测系统，给出了ＴＣ－ＭＤＰＳＫ信号星座、相位差信分支量度间的内在联系，着重分析了在加性高斯白噪声（ＡＷＧＮ）信道中修正的Ｖｉｔｅｒｂｉ算法原理及简化过程。模拟结果表明，该算法不仅降低了译码复杂度，而且译码性能有了相应的提高。     

格状编码和RS码级连技术在HDTV中应用的性能模拟

设计一种用于ＨＤＴＶ地面数字传输系统的级连格状编码和ＲＳ码方案，并对其在ＨＤＴＶ中应用进行计算机模拟。模拟结果表明：该级连格状编码方案在低信噪比具有较好的误码性能。     

角度调制信号调制指数盲估计研究

 调制指数估计在角度调制信号的解调、FM／PM识别等应用中具有十分重要的意义。分析了基带为单音、PSK、FSK等信号时角度调制信号的时频结构,进而建立了信号的统一数学表达式,由此推导并提出了一种无需任何先验信息的调制指数估计方法。仿真实验表明：该方法能有效估计上述基带调制时的角度调制指数。     

Nonlinear multi-h phase codes for CPFSK signaling

Two novel trellis-coding techniques, called nonlinear multi-h signaling and nonlinear asymmetrical multi-h signaling, which achieve higher constraint length than ordinary multi-h signals, are introduced with CPFSK signals. In contrast to ordinary multi-h signaling where the modulation index is changed at the end of every symbol interval, nonlinear multi-h signals are constructed by changing the modulation index based on the previous symbol, and the current symbol interval. A class of nonlinear asymmetrical multi-h signals, which change the modulation index based on the current symbol too, is then constructed by extending nonlinear multi-h signals and combining them with asymmetrical multi-h signals. Binary full-response nonlinear multi-h and nonlinear asymmetrical multi-h CPFSK signals are constructed and analyzed. Minimum Euclidean distances and spectral properties of these signals are calculated at different phase states and various selected modulation index patterns. Numerical results indicate that nonlinear multi-h and nonlinear asymmetrical multi-h signals achieve significantly higher distance than other existing multi-h formats reported in the literature     

突发自适应调制信号的调制识别算法研究

针对突发自适应调制信号中的PSK和QAM调制方式识别问题,本文提出了一种能够识别BPSK、QPSK、8PSK以及16QAM、32QAM、64QAM、128QAM、256QAM八种信号类型的盲识别算法。该算法首先对信号的循环平稳性进行了分析和讨论,给出了利用循环高阶累积量的特征实现信号识别分类的理论依据。然后,提出了三种基于循环累积量的特征分别实现了QAM和PSK类间识别、MPSK类内识别以及方形QAM与十字形QAM的识别。最后通过对MQAM信号的瞬时幅度分布特性的深入研究和分析,提出了一种基于瞬时包络平方的方差的特征实现了QAM的类内识别。该算法选择了二叉树支持向量机作为识别分类器,并设计了一种新的识别流程完成了对上述信号调制方式的识别。该算法无需精确同步,对载波相位具有较好的鲁棒性,并能够对中频信号进行识别。仿真实验表明,该算法能够实现在较低信噪比条件下突发信号的识别。      

Research on Properties of Devices for Shaping and Processing of Signals Based on Amplitude Modulation of Many Components

Devices for shaping and processing of signals based on known varieties of digital amplitude-phase modulation are considered. Their disadvantages are exposed during realization of modulation and demodulation of the signals that are characterized by non-rectangular signal constellations. There are explored properties of devices for shaping and processing of signals based on a new variety of signal modulation, namely amplitude modulation of many components (AMMC). The results of carried out researches show that advantages of proposed AMMC modulator are simplification of phase modulated or amplitude-phase modulated signal shaping, in particular AMMC signal shaping, and improve of modulator internal interference protection. Advantages of AMMC demodulator are simplification of phase modulated or amplitude-phase modulated signal processing, in particularAMMC signal processing, and improve of demodulator internal interference and zero drift protection at its practical realization. The proposed AMMC modulator and demodulator can be applied for shaping and processing of signals based on known and new varieties of amplitude-phase modulation.     

一种有效的BPSK/QPSK信号调制识别方法

根据不同调制信号相位差分的变化规律,文章提出了基于相位差分峰值幅度比较的BP SK/QPSK调制识别方法。仿真结果验证了调制识别方法的有效性。     

Properties and performance of the IEEE 802.11b complementary-code-key signal sets

We describe similarities and differences between complementary-code-key (CCK) modulation and modulation that is derived from biorthogonal signals, and we present performance results and other information that may be useful to those who have applications for CCK modulation that do not require IEEE 802.11b compliance. The properties and performance of the highrate IEEE CCK 802.11b modulation formats are investigated and compared with the properties and performance of alternative modulation formats that are based on biorthogonal signals. Several complementary properties are derived for the full-rate (11 Mb/s) CCK signal set, the half-rate (5.5 Mb/s) CCK signal set, a full-rate signal set obtained from biorthogonal signals, and a half-rate biorthogonal signal set. Each signal set is a complementary set, but each also has stronger complementary properties. We evaluate the performance of IEEE 802.11b standard CCK modulation, CCK with certain modifications that depart from the IEEE standard, and modulation that is derived from biorthogonal signals. Performance comparisons are presented for additive white Gaussian noise (AWGN) channels and for channels with specular multipath. In particular, for AWGN channels, we provide an accurate analytical approximation for the frame error probability for full-rate CCK modulation.     

基于时频特征的跳频信号调制识别

跳频信号在抗干扰方面具有良好的性能。准确识别跳频信号的调制方式,能够为判断敌我目标属性、干扰敌方信号等军事信息战提供有力支撑,但国内外对于跳频信号的调制识别仍存在很大空缺。本文提出一种基于时频特征的跳频信号调制识别方法,通过平滑伪魏格纳-维利分布(SPWVD)时频变换获取不同调制类型的跳频信号时频图像,将时频图像送入卷积神经网络(CNN)中进行特征提取及分类识别。仿真实验证明,本文CNN在低信噪比下取得了较好的识别效果。     

激光诱导声信号通信技术的初步研究

构建了激光声实验测量系统,利用脉冲激光聚焦击穿水介质产生声信号,由水听器将声信号转换成电信号并送入数字存储示波器.分析了激光声信号的时频域数学模型,通过实验对单个激光声信号的时频域特征进行了研究,对激光声通信的信号调制方式进行了理论分析和实验验证.研究结果表明:激光声信号的脉宽约为20s,其能量主要集中在200 kHz内,这其中100~200 kHz内的能量占到的比例大约有50%,通过对激光声信号进行幅度调制和频率调制,可以有效实现激光声通信过程.     

一种基于数字重采样的多载波调制方法

提出一种基于数字重采样的多载波调制方法,该方法先将不同速率的基带调制信号变换到相同的采样速率,并根据分配的频点分别进行数字上变频,然后进行数字合路,最后再将合路后的数字信号送专用芯片进行数字中频调制。与传统的基于中频合路的多载波调制方式相比,具有硬件实现简单、通道一致性好和易于调试的特点。     

基于光纤光栅的超宽带信号产生与传输

针对现有方法功率利用率低与调制实现困难的问题,采用基于光纤光栅（FBG）的超宽带（UWB）调制信号产生方法,建立了UWB信号产生系统。不仅可以实现UWB信号的调制,而且提高了产生信号的信噪比。实现了二进制相位调制（BPM）、脉冲幅度调制（PAM）和脉冲位置调制（PPM）等UWB信号产生。分析了光纤传输对产生信号的影响,...