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本文基于双极晶体管的工艺,就如何对电流增益和特征频率两个参数进行优化研究.首先对其进行了器件工艺模拟分析优化,得到模拟特征频率在10 GHz,电流增益为160,而后进行了流片,通过测试得到特征频率为9.5 GHz,电流增益在160以上,最后进行了测试结果和模拟结果的比较分析. 相似文献
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通过对一种低功耗高噪声源真随机数发生器(TRNG)的研究,设计了一种新型的低频时钟电路,可以把电阻热噪声放大100倍以上,从而减少低频时钟电路的带宽和电阻值,使电路的面积和功耗减少,并且使低频时钟的jitter到达58.2 ns。电路采用SMIC 40 nm CMOS工艺设计,完成了流片和测试,真随机数产生器输出速度范围为1.38~3.33 Mbit/s,电路整体功耗为0.11 mW,面积为0.00789 mm2。随机数输出满足AIS31真随机数熵源测试要求,并且通过了国密2安全测试。 相似文献
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设计了一款宽带CMOSLCVCO,在分析VCO相位噪声来源的基础上,对VCO进行了结构优化和噪声滤除,并采用了开关电容阵列以增加带宽。电路采用0.18μmCMOS射频工艺进行流片验证,芯片面积为0.4mm×1mm。测试结果显示:芯片的工作频率为3.34~4.17GHz,中心频率为4.02GHz时输出功率是-9.11dBm,相位噪声为-120dBc/Hz@1MHz,在1.8V工作电压下的功耗为10mW。 相似文献
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通过对自主设计流片的Ka波段LTCC滤波器的分析,总结出了一套行之有效的Ka波段LTCC模块的设计方法。试验结果表明,这种将电磁场仿真和实际测试相结合的方法,有效地减小由于模型和工艺误差带来的电路性能的降低,其最终测试结果为在26~30GHz的4GHz带宽范围内带内损耗为1.3dB,输入输出驻波均小于1.5dB。 相似文献
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在射频接收机的设计中,由于滤波器的带宽和频率源的限制,一般接收机的带宽无法达到几百兆的超带宽范围.设计一种超带宽射频信号的接收方法,通过五路功分和合理选择射频器件,可以在保证信号指标要求的情况下,有效地对250 MHz带宽的射频信号进行接收和下变频.最后通过ADS软件进行射频仿真分析,验证了本接收方法的主要指标满足要求. 相似文献
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本文研究了一种具有新型分立介质支撑的翼片加载螺旋带慢波系统,该种慢波系统具有较高的功率容量和较宽的带宽.通过用切比雪夫多项式来展开螺旋带上的面电流,用真空层来模拟螺旋带的厚度,用均匀分层介质来等效新型分立介质支撑,考虑到过渡连接金属块的影响,用场论的方法得到了非常实用的色散方程和耦合阻抗的表达式,同时进行了HFSS模拟,发现用场论的方法所得出的结果与用HFSS模拟的结果吻合良好.本文的结果对这种新型慢波结构的设计具有指导意义. 相似文献
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《Microwave Theory and Techniques》1967,15(12):687-694
Compression filters with bandwidths up to 1000 MHz have application in high-resolution RADAR system and rapid-scan receiver systems. A technique is presented for realizing a microwave linear delay (quadratic phase) versus frequency compression filter with sufficient delay accuracy to make compression ratios of up to 1000 to 1 feasible. The dispersive element in the compression filter is a silver tape with its broad side placed perpendicularly between the ground planes (instead of parallel, as in conventional stripline). The tape is folded back and forth upon itself in such a way that substantial coupling takes place between adjacent turns of the tape. A computer program has been written to determine the dimensions of the tape to achieve a linear delay versus frequency characteristic. A folded tape compression filter was constructed with a differential delay of 1.2 /spl mu/s over a bandwidth of 600 MHz centered at 1350 MHz giving a compression factor of 720 to 1. This filter was constructed in four identical sections, each section of which had a differential delay of 0.3 /spl mu/s over the same bandwidth as the complete filter. The entire filter (four sections) occupies a volume about 16 by 4 by 5 inches. Measurement data are presented which illustrate that the desired accurate delay characteristic was realized to within the /spl plusmn/ 1 ns measurement uncertainty. 相似文献
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A novel ground taper has been designed and then fabricated using a laser cutter. The taper is used to match the transition between a suspended microstrip line and a microstrip line. This transition is used in the design of a 25 GHz suspended patch antenna deposited onto a polyimide tape and yields an 18% fractional bandwidth 相似文献
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The system described here was developed in order to record the pseudorandom scan television signal developed by Deutsch. The objective was to investigate the possibility of recording a 200 kHz video signal on a 1/4 in tape running at 15 in/s. The difficulties which arise in such a task are two-fold: 1) bandwidth limitations of the recorder; and 2) flutter and skew of the recorder. Since a tape recorder at this speed has a bandwidth of about 45 kHz, time-division multiplexing was used to reduce the signal into low-frequency signals. The problem is to reassemble the signals at playback. This is a difficult task since these signals are shifted in time randomly by flutter and skew. Experiments disclose that the skew is linearly distributed across the tape; therefore, by knowing this time shift between two tracks at any instant, the position of the appropriate sample at any other track can be predicted. For skew and flutter compensation purposes two reference signals are recorded on the two outer tracks of the tape. The phaseshift of the reference signals at playback is used as a measure for the skew prediction system for each track. Thus the video signals are sampled at the correct value. In order to reassemble the samples in the correct time sequence, they are stored in analog memory cells. The memory cells are read out with the aid of an oscillator which is in turn synchronized with flutter. The deflection waveforms are also generated synchronous with this oscillator. 相似文献
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The main purposes of this article are to lessen the influence of the fastchanging network topology, rapidly varying bandwidth information, and the increasing size of routing tables onquality of service routing. Based on DSDV (Destination-Sequenced Distance-Vector) routing protocol formaintaining up-to-date routing information, the related research has to update routing tables when networktopology changes; moreover, the routing tables must be updated periodically even though the networktopology has not changed. To put emphasis on QoS routing, they also have to exchange routing tables by thetime of bandwidth information changes. Furthermore, the size of routing tables increases with the numberof mobile nodes; therefore, the precious wireless bandwidth is wasted on transmitting the large-scalerouting tables. In this article, we propose an on-demand-based QoS routing protocol to mitigate theseproblems and to achieve the QoS requirement. The goal of this article is to discover an optimal routewith minimum time delay for transmitting real-time data from a source node hop by hop to adestination node under some predefined constraints. Our contributions are as follows: our researchprovides a rigorous bandwidth definition and bandwidth application, a broad view of bandwidth calculationand reservation, minimizing the size of control packets and the number of control packet transmissions,and an efficient QoS routing protocol. 相似文献
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Mostafa M. Fouda Hiroki Nishiyama Ryu Miura Nei Kato 《Wireless Personal Communications》2014,74(4):1311-1327
In recent time, a great deal of research effort has been directed toward promptly facilitating post-disaster communication by using wireless mesh networks (WMNs). WMN technology has been considered to be effectively exploited for this purpose as it provides multi-hop communication through an access network comprising wireless mesh routers, which are connected to the Internet through gateways (GWs). One of the critical challenges in using WMNs for establishing disaster-recovery networks is the issue of distributing traffic among the users in a balanced manner in order to avoid congestion at the GWs. To overcome this issue, we envision a disaster zone WMN comprising a network management center. First, we thoroughly investigate the problem of traffic load balancing amongst the GWs in our considered disaster zone WMN. Then, we develop traffic load distribution techniques from two perspectives. Our proposal from the first perspective hinges upon a balanced distribution of the bandwidth to be allocated per user. On the other hand, our second perspective considers the dynamic (i.e., varying) bandwidth demands from the disaster zone users that requires a more practical and refined distribution of the available bandwidth by following an intelligent forecasting method. The effectiveness of our proposals is evaluated through computer-based simulations. 相似文献
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Bandwidth Estimation for IEEE 802.11-Based Ad Hoc Networks 总被引:1,自引:0,他引:1
Sarr Cheikh Chaudet Claude Chelius Guillaume Gu rin Lassous Isabelle 《Mobile Computing, IEEE Transactions on》2008,7(10):1228-1241
Since 2005, IEEE 802.11-based networks are able to provide a certain level of Quality of Service by the means of service differentiation, thanks to the IEEE 802.11e amendment. However, no mechanism or method has been standardized to accurately evaluate the amount of resources remaining on a given channel. Such evaluation would however be a good asset for bandwidth-constrained applications. In multi-hop ad hoc networks, such evaluation becomes even more difficult. Consequently, despite the various contributions around this research topic, the estimation of the available bandwidth still represents one of the main issues in this field. In this article, we propose an improved mechanism to estimate the available bandwidth in IEEE 802.11-based ad hoc networks. Through simulations, we compare the accuracy of the estimation we propose to the estimation performed by others state of the art QoS protocols, BRuIT, AAC and QoS-AODV. 相似文献
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为了充分减小空间望远镜发射的质量和体积,适应微小卫星的运载需求,针对某光学系统设计了一种基于带状弹簧的新型空间望远镜自展开机构。首先,根据理论分析确定了所用带状弹簧的几何尺寸,并针对某空间光学系统设计了一种基于带状弹簧的新型展开机构;其次,建立了该展开机构的有限元模型并分析了其展开后的特性;最后,搭建了原理样机并对其进行了实验研究。实验结果表明:该展开机构展开后的高度为500 mm,展开后的重复精度误差小于0.1 mm,偏心小于0.1 mm,且展开后的一阶自然频率为35.5 Hz,与有限元分析出的结果相符,其误差为5.3%,能够满足空间望远镜展开机构的结构简单、质量轻、稳定可靠、精度高等要求。 相似文献