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Search Results: 1 - 10 of 87311 matches for " 吴南 "
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利用同步信息修正的LDPC和积译码
LDPC Sum-Product Decoding Based on Synchronized Information
 [PDF]

陈洋洋,
Hans Journal of Wireless Communications (HJWC) , 2015, DOI: 10.12677/HJWC.2015.53010
Abstract:
低密度奇偶校验码(LDPC)是一类具有稀疏校验矩阵的线性分组码,和积算法是理论可行的LDPC软解码算法,但其实用受制于计算复杂度。最小和算法及其它已知改进算法采用近似来有效简化每次迭代的过程,以部分性能为代价,在一定程度上弥补了前述缺陷。本文提出了基于同步信息修正的和积算法,在保持原算法每次迭代复杂度以保证性能的前提下,利用同步信息对算法进行修正,有效减少了算法迭代次数,因此降低了计算复杂度,提高了实用性。
Low density parity check code (LDPC) is a subclass of linear block code with sparse check matrix. Sum-product algorithm is efficient for decoding LDPC theoretically, but not practically due to its complexity. Improved algorithms including minimum sum algorithm reduce computational com-plexity by approximation but performance is degraded. In this paper, we introduce corrected sum-product algorithm based on synchronized information, which improves the practicability by reducing the iterations without performance degradation.
基于冲击滤波器的EBPSK软解调研究
Research on EBPSK Soft Demodulation Based on Impact Filter
 [PDF]

胡琪,
Hans Journal of Wireless Communications (HJWC) , 2015, DOI: 10.12677/HJWC.2015.56016
Abstract:
研究了EBPSK信号在冲击滤波器下的软解调的可行性与性能。在EBPSK解调端,一般使用冲击滤波器。由于其非线性以及IIR的特性,所以EBPSK的软解调一直是个难题。本文参照BPSK解调的软解调,在高斯信道下,从理论上给出了其软信息的形式,并将接收端的冲击幅度减去门限的绝对值作为接受信号的可靠性度量,验证了其可行性,并采用Chase-3方案仿真了此软解调方案的性能,结果比硬解调性能提高了0.5 dB左右。
This paper researches the possibility and performance of EBPSK soft demodulation based on impact filter. We use impact filter to demodulate EBPSK signals generally. Because of the impact filter’s nonlinear character, it is hard to implement EBPSK soft demodulation. Referring to BPSK soft demodulation in Gaussian channel, this paper puts forward the theoretical soft information formula which is the critical point of soft demodulation, and verifies the rationality of the formula. Chase-3 algorithm is used to simulate this soft demodulation scheme and the simulation results show that soft demodulation scheme increases 0.5 dB compared with hard demodulation.
催产素——爱与信任的荷尔蒙

科技导报 , 2015,
Abstract: OT是由下丘脑的视上核和室旁核的细胞分泌的9肽激素,在分娩和哺乳等情况下会大量分泌,能够起到止痛或镇定作用,对于产妇的顺利分娩和产后哺乳具有重要作用。
做一名“靠谱”的博士生

科技导报 , 2014,
Abstract: 在我的毕业典礼上,导师对我说“在我的实验室,你不算聪明,但却是最努力的一个,也是最靠谱的一个”。听到这样的评价,回想起4年“悲催”、“辛酸”的博士研究生光景,我泪如泉涌。对于我这样一个外校生,而立之年进入北大攻读博士,期间的种种辛劳付出,遭受的失败与嘲笑,郁结于心中,久久不能释怀,伴随着导师给予的肯定,那一刻所有情绪全部释放。4年博士学习生活,最大的收获是做科研如同做人,要靠谱。
无线携能通信研究进展
Advances in Simultaneous Wireless Information and Power Transfer
 [PDF]

郑祖翔,
Hans Journal of Wireless Communications (HJWC) , 2013, DOI: 10.12677/HJWC.2013.36025
Abstract: 本文首先概要分析了无线携能通信技术的需求与前景,综述了国内外在无线能量传输(Wireless Power Transfer, WPT)和无线信息传输(Wireless Information Transmission, WIT)领域的研究现状。进而构思了无线携能通信系统的体系架构,并分析了该系统的信息调制方案、WPT方式以及动态功率分配(Dynamic Power Splitting, DPS)方案。最后,对采用超窄带调制技术作为无线携能通信系统的信息调制方案的合理性与性能进行了仿真与分析。
The needs and prospects of Simultaneous Wireless Information and Power Transfer (SWIPT) are analyzed at first. Development history and principal applications of Wireless Power Transfer (WPT) and Wireless Information Transmission (WIT) are summarized. On this basis, framework of SWIPT system is conceived. Moreover, the modulation schemes, the dynamic power splitting (DPS) methods and the main techniques used in WPT are discussed in details. Finally, the simulation performance of Ultra-Narrow Band (UNB) used as a novel high efficiency modulation scheme in SWIPT is illustrated and analyzed.
基于电导率的地沟油快速鉴别方法的改进
Improvement on the Rapid Detection Method of Waste Oil Based on Electrical Conductivity
 [PDF]

胡雪瑶,
Applied Physics (APP) , 2013, DOI: 10.12677/APP.2013.38030
Abstract:

以合格食用油和地沟油为样品,探究油脂种类、温度、水油比例对电导率检测影响,找出能更准确更快的检测油脂电导率的条件。本实验采用的方法是取油样10 ml时,加正己烷25 ml,去离子水30 ml,70℃恒温水浴振荡30 min,分离油、水相,再将水相置于70℃水浴中测其电导率。在此条件下,由于去离子水的增加,分离出更多更清澈的水相使检测时水相能将电极完全淹没,减小了由于电极不能完全淹没在水中而产生的误差;升高振荡时的水浴温度,振荡后不用静止马上就能分离出清澈的水相,缩短了实验时间,水相清澈减小了由于水相中含有油珠而对电导率检测产生的影响,而且升高振荡时的水浴温度使油脂中的杂质或离子能尽可能全部溶解到水中,更准确的反映油脂中含杂质或离子情况;升高检测时的水相温度使合格油与地沟油间的电导率差距变大,减小了把电导率处于中间的合格油判为地沟油或把地沟油判为合格油的可能。同时,保持检测时水相的温度与分离油、水相时的温度一致,能更准确的反应分离时杂质或离子在水相中的溶解情况。因此该方法不但大大提高了检测电导率的准确性,还提高分离速度。
Using the qualified edible oil and waste oil for sample, we explore the influence of oil types, temperature, the ratio of water and oil for electrical conductivity, to find out a test condition which can faster and more accurately detect grease conductivity. This method adopted in the experiment is that inject n-hexane 25 ml, 30 ml deionized water, then vibrate 30 min in 70?C thermostatic water bath to separate the oil and water phase, then put the water phase in 70?C thermostatic water bath measuring the conductivity when the 10 ml of sample is taken. On this condition, it can extract clearer water which can make the pole be completely submerged when detection, thus it reduces the error because the pole can not be completely submerged in water. Because the water bath temperature has risen higher, the clear water can be fleetly separated from mixture sample after vibration, hence it shortens the time of experiment. Clear water reduced the influence of oil droplets for conductivity detection, and the rising bath temperature of vibration can make impurities or ions in oil dissolve in water as much as possible, thereby, the measuring result can more accurately reflect the condition of impurities or ions in oil. Rising the bath temperature of detection increased the conductivity gap of qualified oil and waste oil, thus the possibility of mis-judgement was reduced, meanwhile, keeping water temperature of detection and separation the same can more accurately reflect the condition of impurities or ions in water when separation. Therefore, this method not only boosts veracity of conductivity detection, but also increases speed of separation.

EBPSK-MODEM的抗单径瑞利衰落算法
Anti-Single Path Rayleigh Fading Algorithm Based on EBPSK-MODEM
 [PDF]

张陈梅,
Hans Journal of Wireless Communications (HJWC) , 2015, DOI: 10.12677/HJWC.2015.54011
Abstract: 扩展的二元相移键控(Extended Binary Phase Shift Keying, EBPSK)是一种高效调制方式,针对冲击滤波器可将EBPSK调制信息转化为幅度冲击的特点并引入插值思想,本文提出了两种抗单径瑞利衰落算法:插值估计衰落因子和插值估计判决门限。仿真结果表明,这两种算法对EBPSK-MODEM系统的性能均有不同程度改善,其中以插值估计判决门限算法对系统的性能改善效果优于插值估计衰落因子算法。
Extended Binary Phase Shift Keying (EBPSK) is an efficient modulation mode. According to the characteristic that the impacting filter based demodulator would transform the EBPSK modulating signal into impact amplitude, and the interpolation thought, two new anti-single path Rayleigh fading algorithms aimed at EBPSK-MODEM scheme are put forward, which are interpolation algo-rithm estimating fading factor and interpolation algorithm estimating the decision threshold. The simulation results show that the two algorithms improve the performance of EBPSK-MODEM sys-tems to varying degrees. Among them, the performance of the interpolation algorithm estimating decision threshold is slightly better than interpolation algorithm estimating fading factor.
MPPSK接收机位同步实现
Phase Synchronization in MPPSK Receiver
 [PDF]

施昱阳,
Hans Journal of Wireless Communications (HJWC) , 2015, DOI: 10.12677/HJWC.2015.56021
Abstract:
鉴于多元位置相移键控(MPPSK)是一种基于位置的调制方式,在硬件解调器中相位同步尤为重要。本文提出一种MPPSK信号解调器的位同步方式,将利用MPPSK调制自身的信号特性实现同步,核心在于找到每个符号周期的起始位置,将MPPSK的调制位置定位到正确的判决区间中,并利用解调信号的反馈对接收信号进行实时相位微调,尤其在非整数倍采样时,能消除因采样点个数取整而引入的相位偏差。
As M-ary Position Phase Shift Keying (MPPSK) is a phase-based modulation and phase synchroni-zation is particularly important in actual demodulation system. This paper presents a method of phase synchronization using signal characteristics of MPPSK modulation. The key step is to find the beginning of each symbol period, which will help to locate the correct decision interval and conduct the real-time phase trimming with feedback of demodulated signal. This method can eliminate phase deviation especially in the case of non-integer multiple sampling.
基于改进型脉冲MPPSK调制的WSN节点建模分析
Modeling and Analysis of WSN Node Based on Improved Pulse MPPSK Modulation
 [PDF]

王何浚,
Hans Journal of Wireless Communications (HJWC) , 2015, DOI: 10.12677/HJWC.2015.56017
Abstract:
无线传感器网络(Wireless Sensor Networks, WSN)节点是物联网构成的关键部分,其中电池的使用寿命是制约其发展的重要因素。脉冲MPPSK调制比连续MPPSK调制拥有更高的能量利用率,非常适合作为WSN节点的通信方式。本文通过对基于改进型脉冲MPPSK调制的WSN节点进行建模,推导出了每单位比特能耗的公式,并按照节点间距离进行了仿真验证。
The nodes of Wireless Sensor Networks (WSN) are key part of the Internet of things. The life of the battery is an important factor which restricts its development. Pulse MPPSK modulation, which is suitable for the communication mode of WSN nodes, has a higher energy utilization rate than con-tinuous MPPSK modulation. In this paper, we model the WSN node based on the improved pulse MPPSK modulation, and derive the formula of the energy consumption per bit. At the end of this paper, the simulation results are carried out according to the distance between the nodes.
MPPSK/AM复合调制系统优化方案
Optimization Scheme of MPPSK/AM Hybrid Modulation System
 [PDF]

盛旭嫣,
Hans Journal of Wireless Communications (HJWC) , 2016, DOI: 10.12677/HJWC.2016.61004
Abstract:
本文给出一种兼容AM广播的MPPSK/AM复合调制系统,为了提升数字信号的解调性能,需要增加MPPSK调制中的K值。而这同时也增加了数字信号与音频信号的频谱混叠,所以本文通过在发送端添加双带阻滤波器,使数字信号不占用音频信号的频段从而提升音频信号解调性能。并且根据贝叶斯公式得出的概率信息表格作为信道解码的软信息进行软判决译码进一步提升数字信号解调性能。
This paper presents a MPPSK/AM Hybrid Modulation System which is compatible with the existing AM broadcast. While it causes the aliasing of digital signal and audio signal spectrum to increase the K value of MPPSK for the improvement of digital signal demodulation performance, thus double band-stop filter is added in the sender, making the digital signal not take up the audio signal frequency band to increase the audio signal demodulation performance. And soft decision decoding based on information table from Bayesian probability formula is obtained as soft information for channel decoder to further enhance the digital signal demodulation performance.
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