A Receiver in a Millimeter Wave Radiometer for Atmosphere Remote Sensing

A millimeter wave radiometer system with high resolution is described in this paper, which was used for remote sensing of integrated water vapor and integrated liquid water in the troposphere. A novel receiver technique was adopted in the radiometer system to deracinate an impact of the receiver gain shift on its precision and improve its performance. Measured results show that this radiometer system has enough stability in long time measurement and capability to measure atmospheric brightness temperature.     

一种高性能Class D音频放大器PWM控制的设计

文中设计了一种应用于Class D音频放大器中高性能PWM控制。该控制能够在较宽的电源电压范围内,使调制锯齿波的输入电平及音频输入信号经过前置放大后的共模电平跟随电源电压的变化而变化。共模电平经过PWM比较器得到占空比随输入信号变化的控制信号,从而提高系统的输出功率。仿真结果显示,当电源电压在2．4-5V范围变化时．音频信号和调制锯齿波的共模电平偏差在2mV以内,同时锯齿波的幅度也随着电源电压的升高而升高．显示了良好的线性跟随性。     

有限域上一种新的求逆电路

求逆运算在编码理论和密码学中有着广泛的应用,因此设计简洁高效的求逆电路具有重要的现实意义。基于线性反馈移位寄存器和逻辑门,采用比特串行搜索方法,设计了一种新的应用于有限域上的求逆电路。该电路与用ROM查表法或纯组合逻辑电路实现求逆相比可节省芯片资源,且易于实现,具有广阔的应用前景。     

基于光学技术的船模运动跟踪

为准确获得水池中船舶模型的位置和运动姿态,实时对自由运动的船模进行追踪,文中提出了基于光学技术的船模运动跟踪方法,满足了船模运动跟踪的实时性要求。通过对船模进行特殊标记,并在算法中利用关于Battacharyya系数的高斯函数调节核的大小,在不影响实现Mean Shift算法快速性的同时增强了算法的鲁棒性。实验结果表明,在追踪过程中,该算法能够调节跟踪窗口大小,使目标始终出现在窗口中心位置,提高了算法跟踪的准确性。     

Spectral Feature Analysis of Semiconductor Thin Disk Laser

The semiconductor thin disk laser is a new type of semiconductor laser. This work gives the basic operation function of the semiconductor disk laser, and analyses the heat effect by the experimentally measured photoluminescence spectrum of the laser chip at different pump power and different temperatures. We can see that: with increasing pump power, the thermal effect of the gain material becomes seriously and causes the saturation of carrier lifetime, so the electron-hole pair created in the absorbtion lay...     

液晶光学相阵列相移单元的电压-相移特性

液晶光学相阵列是一种新型的光学相位调制器件,为分析器件中相移单元的电压-相移特性,建立了液晶相移单元的数学模型,并提出了一种混合差分迭代算法。该算法根据液晶分子在电场作用下的物理变化过程,在指向矢与电位的耦合迭代过程中,采用追赶法计算相移单元中的电位分布。根据该算法对相移单元中液晶指向矢的分布进行了仿真计算,进而对取向膜厚度、预倾角和液晶盒厚度对器件的电压-相移特性的影响进行了分析。结果表明,当电压处于阈值电压与饱和电压之间时,取向膜厚度对液晶的电压-相移特性的影响比较明显。     

一种新型任意多模移位计数器

提出了一种新型移位计数器,用实例讨论了各种双模、多模移位计数器的设计。因为移位计数器的设计可查已有的反馈函数表达式,所以十分容易。这种新型移位计数器不仅可以用于在吞脉冲技术中提高前置分频器的工作速率,而且特别适宜在有较大延迟的反馈控制系统中使用。     

The effects of PMD and PDL on the performance of OOK and DPSK systems

Using multiple importance sampling （MIS） technique, the optical communication system performance affected by polarization-mode dispersion （PMD） and polarization-dependent loss （PDL） is simulated numerically. The power penalties and system outage probabilities are obtained for optical communication systems with on-off keying （OOK） or differential phase shift keying （DPSK） modulation. The simulation results show that DPSK always performs better than OOK. When the system has moderate PDL （about 1.5 dB）, it is necessary to compensate effectively the fiber PMD in order to enhance the system tolerance to the PMD and PDL. However, the efficiency of PMD compensation will degrade rapidly when the PMD of the whole optical link drops into the low value.     

Partial scan design and test sequence generation based on reduced scan shift method

This paper presents a partial scan algorithm, calledPARES (PartialscanAlgorithm based onREduced Scan shift), for designing partial scan circuits. PARES is based on the reduced scan shift that has been previously proposed for generating short test sequences for full scan circuits. In the reduced scan shift method, one determines proch FFs must be controlled and observed for each test vector. According to the results of similar analysis, PARES selects these FFs that must be controlled or observed for a large number of test vectors, as scanned FFs. Short test sequences are generated by reducing scan shift operations using a static test compaction method. To minimize the loss of fault coverage, the order of test vectors is so determined that the unscanned FFs are in the state required by the next test vector. If there are any faults undetected yet by a test sequence derived from the test vectors, then PARES uses a sequential circuit test generator to detect the faults. Experimental results for ISCAS'89 benchmark circuits are given to demonstrate the effectiveness of PARES.     

IJF－OQPSK数字调制器

无符号间干扰和抖动－交错正交相移键控（ＩＦＪ－ＯＱＰＳＫ）是现代数字调制技术中的一种新的调制方式。在介绍一种新型集成调制芯片的基础上，给出实现ＩＪＦ－ＯＱＰＳＫ调制器的具体电路。