A simple and useful model for Jones matrix to evaluate higher orderpolarization-mode dispersion effects

Starting from the differential equation that relates the Jones matrix of a polarization-mode dispersion (PMD) fiber to its output dispersion vector, the analytical expressions of the matrix coefficients are determined in the case of a dispersion vector rotating on a circumference in the Stokes space. This model, that needs only few parameters with known statistics, is applied to evaluate the performance of an optical system. The results obtained with it and with other models proposed in literature are compared to those evaluated by numerical simulations with all-order PMD effects, showing that our model gives an accurate representation of real system performances     

A simple technique to evaluate the noise spectral density in operational amplifier based circuits using the adjoint network theory

We use the adjoint network theory to get quick estimates of the noise contributed by various elements in linear time-invariant opamp based circuits. The noisy operational amplifier is represented using a or with an input referred noise voltage and current source. The adjoint model for this representation is derived. This makes the noise analysis of operational amplifier based circuits very simple and the contribution of the operational amplifiers to the output noise can be obtained very often by inspection. The method is applicable to amplifiers, active RC and MOSFET-C filters. Examples of circuits analyzed include the universal active filter and gyrator topologies.     

A simple evaluation of losses in thin microstrips

A simple modification of Wheeler's incremental inductance rule is presented which allows the extention of the use of this rule for the evaluation in quasi-TEM operation of losses in thin microstrips (i.e., when the Wheeler's rule is considered no longer applicable). A good agreement of the proposed formula with available numerical results is obtained when thickness is comparable with skin depth. A comparison is also made with two approximate formulas proposed by some authors. The proposed modification to Wheeler's rule should be useful for computer-aided design (CAD) of monolithic microwave integrated circuits (MMIC's)     

A simple method to evaluate device lifetime due to hot-carrier effect under dynamic stress

A method to evaluate hot-carrier-induced NMOSFET degradation under dynamic stress is discussed, based on an empirical relation between device lifetime and substrate current in static stress. The device lifetime τ under dynamic stress is given bytau = A.I_{sub,peak}^{-2.5}/R, whereI_{sub,peak}is the peak value of pulsive substrate current and R is its duty ratio. The device lifetime experimentally obtained in an inverter circuit is in good agreement with the calculation results obtained from the proposed method. This method is useful to estimate device lifetime in actual circuit operational conditions.     

A simple power control technique

An open-loop power control technique that establishes a linear relationship between a d.c. control voltage and the average load voltage is described. The output voltage is insensitive to input a.c. line voltage fluctuations as well as variations in supply frequency. The control output is versatile enough to drive a semiconductor on/off switch or an s.c.r. bridge operating either as a rectifier or as an inverter.     

A simple method to evaluate the plasma spreading velocity in high power thyristors

The experimental determination of plasma spreading velocity versus current density in high power thyristors has been performed by many authors in different ways, especially by means of the observation of infrared recombination radiation [1], [2], [3] and the measurement of voltage with electrical probes [1], [4], [5]. In this paper a method is presented which, from the forward dynamic voltage measurement on finished devices, allows, on particular structures, to calculate analytically the experimental constants that appear in the relation between plasma velocity and current density.     

A simple method to account for edge shape in the conductor loss inmicrostrip

A technique has been developed to examine the effect of strip edge shape on conductor loss in planar transmission lines using a modified incremental inductance rule. Based on L. Lewin's (1984) and L.A. Vainshteins's and S.M. Zhurav's (1986) zero-thickness strip perturbation in loss calculations, the method requires an expression for the infinitely thin strip inductance as well as prescribed integration stopping points for the different strip shapes. Results comparing losses for different edge shapes in a microstrip system are given, using this method and the Lewin/Vainshtein and Zhurav technique. The differing results of some other published analytical and numerical loss methods based on the surface impedance boundary condition are compared     

A simple technique to measure generation lifetime in partiallydepleted SOI MOSFETs

This work presents a new, simple method of measuring the generation lifetime in silicon-on-insulator (SOI) MOSFETs. Lifetime is extracted from the transient characteristics of MOSFET subthreshold current. Using this technique, generation lifetime was mapped across finished SIMOX (Separation by IMplantation of OXygen) wafers and BESOI (Bonded and Etchedback SOI) wafers. BESOI material evaluated in this study had about seven times longer effective generation lifetime than SIMOX material and both the SIMOX and the BESOI are shown to have a lifetime variation of ±10% across four inch wafers     

一种实现多通道全息干涉计量的简易方法

目前对于多通道全息术已经作了比较充分的研究。这种技术对多种不同物体的记录和比较或对同一物体的多种状态的记录与比较是十分有用的。已经成功地用于干涉计量的多通道全息术有对记录干板进行区域编码记录和采用多路参考光进行编码记录技术,实时全息术和夹层全息术也可以进行多状态全息干涉计量,但需要有精确的复位装置和特殊的编码装置,技术上也很复杂。这里提出一种实现多通道全息干涉计量的简易方法。     

A simple yet effective technique for partitioning

Partitioning is an important step in the top-down design of large complicated integrated circuits. In this paper, a simple yet effective partitioning technique is described. It is based on the clustering of “closely” connected cells and the gradual enforcement of size-constraints. At the beginning, clusters are formed in the bottom-up fashion to reduce the problem size. Then the clusters are partitioned using several different parameters to find a good starting point. The best result achieved during the cluster partitioning is used as the initial solution for the lower level partitioning. The gradual constraint enforcement technique is used to cope with the local minimum problems. It allows cells or clusters to move with more freedom among the subsets during earlier iterations and thus may effectively find a near optimum solution. Several experimental results show that the new partitioning technique produces favorable results. In particular, the method outperforms the F&M method by more than 60% in the number of crossing nets on average     

A simple angular alignment technique for apolarization-maintaining-fiber

Simple and accurate techniques for angular alignment of a polarization-maintaining-fiber (PMF) to a linearly polarized input beam are required for many optical-fiber applications. We consider an alignment technique wherein a short length of PMF undergoes a large temperature excursion and the output beam from the fiber is simply monitored by a linear polarizer and a power meter. Upon carefully considering the results for rotation angles near alignment, an accuracy better than 0.2° as well as a measurement of the fiber crosstalk are obtained     

A simple technique for longitudinal mode selection

Single longitudinal mode operation of pulse-pumpedQ-switched Nd:YAG and ruby lasers has been achieved by providing an intracavity mode-selecting resonator that contains the laser's active medium.     

A simple transmit diversity technique for wireless communications

This paper presents a simple two-branch transmit diversity scheme. Using two transmit antennas and one receive antenna the scheme provides the same diversity order as maximal-ratio receiver combining (MRRC) with one transmit antenna, and two receive antennas. It is also shown that the scheme may easily be generalized to two transmit antennas and M receive antennas to provide a diversity order of 2M. The new scheme does not require any bandwidth expansion or any feedback from the receiver to the transmitter and its computation complexity is similar to MRRC     

A simple control technique for series resonant converters

A control strategy for series resonant converters, based on the control of the state space trajectory, is proposed. Its simple implementation allows high frequency applications and requires only resonant current sensing. Quite linear and load independent control characteristics are obtained. Simulated and experimental results show good steady-state stability, fast dynamic response for wide reference step variations, and well-controlled converter start-up     

A simple wafer-level measurement technique for predicting oxidereliability

A new wafer-level measurement technique, the differential gate antenna analysis, has been developed to detect weaknesses in sub-micrometer oxide. This simple technique involves the use of dual antenna structures with different gate oxide areas but the same antenna area ratio. The critical parameter is the difference in their failure levels. It is shown that such a differential measurement of antenna failures correlates with product failure during accelerated life testing. The differential antenna structures are thus proven useful for real-time wafer-level monitoring of oxide reliability     

A simple edge termination for silicon carbide devices with nearlyideal breakdown voltage

In this paper, a simple edge termination is described which can achieve near ideal parallel plane breakdown for silicon carbide devices. This novel edge termination involves self aligned implantation of a neutral species on the edges of devices to form an amorphous layer. With this termination formed using argon implantation, the breakdown voltage of Schottky barrier diodes was measured to be very close to ideal plane parallel breakdown voltage     

A simple technique to induce and control short pulses of deepdrain-source breakdown conditions

A simple method to induce drain-source breakdown, followed by the parasitic bipolar action, is reported for time intervals and energies sufficiently small to avoid thermal runaway. A relatively large capacitor, connected in parallel to the device under test, is charged up using a sufficiently large resistor and discharges automatically as the breakdown voltage (BV_DSS) is reached, thus eliminating the need for a fast and `ringing-free' switch in the test setup. Since the discharge process is controlled by the small dynamic device resistance, rather than the large external resistor, the resulting transitions are fast enough and therefore compatible with electrostatic discharge (ESD) or latch-up turn-on conditions. Such pulses were successfully used to study soft ESD damage in lightly-doped-drain (LDD) devices, using simple on-wafer probing     

A digital technique for the measurement of power losses in hightemperature superconductors

A digital power loss measurement technique that enables the fast and accurate measurement of AC power losses in superconductors is described. This technique allows loss measurements at all frequencies limited only by the maximum sampling rate and buffer memory of the digital measuring device. Using the digital technique, power loss measurements on YBa₂Cu₃O₇ are compared to similar measurements using the analog wattmeter     

Wave propagation in nonlinear transmission lines with simple losses

Heaviside's condition for distortionless wave propagation in linear transmission lines with losses is generalised to cover nonlinear transmission lines. Analytical expressions are given for voltage and current in these lines.