The tapped delay model of the multi - path frequency selective fading channels as well as the diversity receiver technique is introduced , and the principles of rake receiver are described . then various downlink channel estimation techniques , such as simple averaging , wmsa and fbprelms are analysed in detail 本文首先讨论了移动通信信道的各种参数对信道估计的影响,介绍了频率选择性信道的抽头延迟线模型和分集接收技术,在此基础上阐述了rake接收机的原理。
On the other hand , a new technology using tunable laser as light source of delay system is proposed , which uses the characteristics of optical fiber material dispersion which means that the refraction index of optical fiber changes along with the difference of transmitting wavelength 另一方面,提出一种通过采用可调谐激光器作为系统光源的技术,利用光纤的材料色散特性即光纤的折射率随传输波长变化而改变的特点,来改变延时光纤中信号存储的时间,从而达到提高光纤延迟线延时精度的目的。
Computer simulation results show that the beamspace wsf algorithm retains the super performance of its element space counterpart when applied to the beam outputs of some practical acoustic - receiving array . 3 . an improved form of classical time domain broadband beamforming is proposed by combining digital delay lines and fir filters 提出了对经典时域宽带波束形成器的改进方法，采用数字延迟线和fir数字滤波器结合的方式实现时域波束形成，以消除波束畸变并实时实现结构特殊的空间频率响应。
The microwave delaylines using hts thin films have the advantages of small size and mass and low insertion lose . these characters are much better than the delaylines using surface acoustic wave , coaxial - line , magetostatic wave or conventional metal planar structures . these merits benefit a lot in largely reduction the mass and volume of communication systems 利用高温超导( htsc )薄膜材料研制的微波延迟线具有体积小、重量轻、插损小等优点,这是利用声表面波、同轴线、静磁波或常规金属平面结构设计的延迟线所无法比拟的。这些优点对于减轻通信系统的重量和缩小体积都是非常有利的。
Delay line oscillator is composed of broadband amprifer adjustable attenuator and saw sensor device . after output signal of delay line oscillator is smoothed , it mixes with 109mhz local oscillation signal . its differential frequency signal is smoothed by low - pass filter trimmed by shaping circuit and processed by digital processing circuit 延迟线振荡器由宽带放大器、可调衰减器和声表面波质量传感器件构成。延迟线振荡器输出信号经滤波后与109mhz的本机晶体振荡器输出信号相混频，通过低通滤波取其差频，并经整形后由数字信号处理电路处理。
As far the trend of fiber - optic communication systems is to obtain higher capacity , and higher transmission speed . the intensity modulator is widely applied to a lot of fields . it is necessary for the intensity modulator subject to the laser pulse rectification systems that should be provided with following performances as high speed signal transmission and quick response and so on 光纤通信向着大容量、高速宽带方向发展,光纤延迟线系统要求强度调制器具有高速信号传输、快速响应的特点,因此以linbo _ 3为衬底材料的集成光学强度调制器具有十分良好的应用前景。
Compared to the wavelength routing ( wr ) and optical packet switching ( ops ) networks , optical burst switching ( obs ) is believed to be more attractive technical solution for future . as the performance of obs depend on both switch architecture and schedule algorithm . switch architecture consist of not only switch matrix but also fdl ( fiber delay line ) and twc ( tunable wavelength converter ) 其中交换结构除了交换矩阵本身,还需要大量的可调波长变换器( tunablewavelengthconverter ,简称twc )和光纤延迟线( fiberdelayline ,简称fdl ) ,因此不同的fdl和twc配置造成交换结构具有不同的交换能力,对应的调度算法也不尽相同。
Technology of fine processing was firstly used to make the lsaw biosensor with dual delay linear style . then we developed the dual channels resonance circuit and used the labview software to record and analyze phase / frequency automatically . so the detection system of lsaw biosensor was constructed by combing all these components with network analyzer and computer 方法: 1 .利用精细微加工方法制备双延迟线型漏声表面波传感器,并自行开发研制自激式振荡电路, labview相位、频率记录分析软件,将它们与网络分析仪、频谱分析仪及计算机联用以构建lsaw生物传感器检测系统。
As far the trend of fiber - optic communication systems is to obtain higher capacity , and higher transmission speed . the intensity modulator is widely applied to a lot of fields . it is necessary for the intensity modulator subject to the laser pulse rectification systems that should be provided with following performances as high speed signal transmission and quick response and so on 光纤通信向着大容量、高速宽带方向发展,激光脉冲整形调制时要求强度调制器具有高速调制、高消光比工作特点,光纤延迟线系统要求强度调制器具有高速信号传输、快速响应的特点,因此以linbo _ 3为衬底材料的集成光学强度调制器具有十分良好的应用前景。
A square sensing area was formed upon each of the saw propagation paths using photoresist . when some kind of material deposits on this area , the saw propagation velocity will decrease due to the mass - loading effect , causing a shift in the device ' s oscillation frequency , which gives indication of the mass deposited . the dual - path architecture , one for sensing and one for reference , was used to compensate for the disturbance of temperature 利用光刻工艺在每个声传播路径上构造了一个方形质量沉积区，当有物质沉积到该区时，由于质量沉积效应，声表面波的波速发生变化，使以延迟线作为反馈回路的振荡器的振荡频率发生变化，并通过这一变化反映出沉积物的质量。
