基于被动时间反转-自编码器的水声通信信号调制识别方法

海洋环境中存在的多径效应会影响水声通信信号的特征,降低调制识别准确率.为了减小多径效应对信号调制识别造成的干扰,本文提出了一种基于被动时间反转-自编码器的信号增强方法.利用水声通信信号中常见的同步信号作为探测信号,实现无外加信号的被动时间反转以及功率谱和平方谱两种频域特征的增强,并设计了卷积神经网络进行调制识别.网络模型经过Bellhop仿真水声信道和少量非测试环境的实测数据进行训练后,在3种与训练环境不同的实际水声信道下测试,所有调制信号识别准确率均高于80%,6种调制信号的平均识别准确率与已有文献中的方法相比至少提高了20个百分点.

单片微机时钟信号编码器

由于单片微机价廉，并具有在很小的存储空间内汇编出高智能、高效率的产品程序的优点，本文介绍作者使用４位单位微机设计了一款具有多种制式的帧格式输出时间码的智能时钟编码器。

混合模糊信息粒化和时间序列密集编码器的锂离子电池剩余寿命区间预测方法

锂离子电池的剩余使用寿命(remaining useful life,RUL)是电池健康状态的关键指标,对其进行预测具有重要的现实意义。该工作将模糊信息粒化(fuzzy information granulation,FIG)技术与时间序列密集编码器模型(timeseries dense encoder,TiDE)相结合,提出了一种对锂离子电池的RUL进行区间预测的模型。首先将锂离子电池容量退化时间序列通过FIG技术转化为粒子序列信息,以此得到模糊信息粒子的上下界序列。其次,分别对上下界序列使用TiDE模型进行训练预测,从而得到区间预测的结果。实验结果表明,与基于支持向量回归(support vector regression,SVR)和长短期记忆网络(long short term memory network,LSTM)的区间预测模型以及不使用狐狸优化算法(fox-inspired optimization algorithm,FOA)优化的TiDE模型相比,该工作提出的基于FIG技术结合TiDE模型与FOA的区间预测方法在锂离子电池RUL预测性能上具有更高的可靠性。

拟平移不变信号的自适应采样与重构

在采样问题的研究过程中,时间编码器作为易实现且高效的采样装置被提出。为达到高效重构信号的目的,基于时间编码器对拟平移不变空间中信号的自适应采样与重构展开研究,重点研究拟平移不变信号的重构算法。首先,基于“Crossing”和“Integrate-and-Fire”时间编码器,分别考虑了2种自适应采样方式,并建立了相应的精确重构算法。其次,讨论了一种可以产生有限自适应平均样本的IF采样器,并给出了基于样本的近似重构算法。结果表明,当时间编码器的稠密度满足一定衰减性时,建立的精确重构算法具有指数收敛性;当生成元满足一定衰减性时,近似重构算法的收敛速度线性依赖于IF采样器的阈值参数。

Enhancement of Voice Quality and Bit-rate Reduction by Prosodic Control in G.723.1 Vocoder

Speech coding techniques have been studied not truly to reduce the complexity and bit rate but also to improve the sound quality. CELP type vocoder, used as standard, supports the great stead quality even low bit rate. In this paper, the preprocessing of input speech to reduce the bit rate is different from the conventional vocoder. Different kinds of parameter are used for the preprocessing compared with the other parameters to t＇md the more appropriate parameter for the vocoder. The Parameters are used to synthesize the speech not to encode or decode for coding technique so we proposed the simple algorithm not to have the influence on the processing time or the computation time. The parameters in the preprocessing step are speaking rate, duration, and PSOLA technique.

Fast Motion Estimation Algorithm with Edge Alignment for H.264 Encoder

Image sequences processing and video encoding are extremely time consuming problems. The time complexity of them depends on image contents. This paper presents an estimation of a block motion method for video coding with edge alignment. This method uses blocks of size 4 × 4 and its basic idea is to find motion vector using the edge position in each video coding block. The method finds the motion vectors more accurately and faster than any known classical method that calculates all the possibilities. Our presented algorithm is compared with known classical algorithms using the evaluation function of the peak signal-to-noise ratio. For comparison of the methods we are using parameters such as time, CPU usage, and size of compressed data. The comparison is made on benchmark data in color format YUV. Results of our proposed method are comparable and in some cases better than results of standard classical algorithms.

Design and implementation of space-time precoded systems with full diversity and lossless capacity

A new space-time(ST)code design is proposed based on the design criteria of space-time codes,which is applied to the MIMO systems with fewer receive antennas than transmit antennas.The space-time codes,referred to as full diversity lossless capacity(FDLLC)ST code,achieve full transmit diversity and lossless equivalent channel capacity for ST precoded systems.Combined FDLLC-ST codes with channel codes,ST bit interleaved coded modulation(ST-BICM)system is constructed and an iterative detector/decoder is employed at the receiver.Simulations are presented.It is proved that the proposed design has good performance compared with other ST precoded MIMO systems.