Generation of current conveyor based oscillators using nodal admittance matrix expansion

The residual stress in a polysilicon beam varies throughout its thickness and will cause a freestanding cantilever to curl upwards or downwards. Measurement of stress gradient for cantilever beam MEMS switches was studied by new procedure and its influences on pull-in phenomena of cantilever beam type were studied. The effect of non ideal anchors of fixed–fixed end type MEM switches were investigated in. The Generalized Differential Quadrature Method was used as a high order approximation to discretize the governing nonlinear differential equation yielding more accurate results with a considerably smaller number of grid points. Further, the results obtained were compared with other existing empirical and theoretical models.     

On the systematic synthesis of OTA-based Wien oscillators

A NAM expansion method for systematic synthesis of OTA-based Wien oscillators is given. Moreover, the NAM expansion method for four different classes of the oscillators is considered. The class I oscillators employ three OTAs, the class II oscillators employ four OTAs, the class III oscillators employ five OTAs, and the class IV oscillators employ six OTAs. Each class has 32 different forms, resulting in 128 Wien oscillators using OTAs. Having used grounded capacitors, the circuits are easy to be integrated and their parameters can be tuned electronically through tuning bias currents of the OTAs. The MULTISIM simulation results have been included to support the generation method.     

Generation of second generation current conveyor (CCII) family from inverting second generation current conveyor (ICCII) family

Based on the nodal admittance matrix (NAM) representation of the voltage mirror (VM)–norator pair and considering the case of an inverting second generation current conveyor (ICCII?), it is found that the second generation current conveyor (CCII?) is a special case from the generalised ICCII?. Considering the NAM of the VM–current mirror pair, it is also found that the CCII+ is a special case from the generalised ICCII+.     

Carrier Travel Time in Transistors

A recently reported two current feedback operational amplifier (CFOA)-based oscillator is converted to a family of 16 current mode oscillators using CCII or ICCII or combination of both. A transformation method based on nodal admittance matrix (NAM) expansion is used to transform the floating capacitor CFOA-based oscillator circuit to a family of 16 grounded capacitor oscillators using CCII or ICCII or combination of both. Two of the new grounded capacitor oscillator circuits have a floating property. Simulation results are included.     

Systematic synthesis of CCCCTA-based T-T filters using NAM expansion method

In the light of nullor-mirror models for current-controlled current conveyor trans-conductance amplifier (CCCCTA), initiating the admittance matrices of the Tow-Thomas (T-T) filter, three different types of the T-T filter are synthesised by means of the nodal admittance matrix (NAM) expansion method. The type A filter, which employ one CCCCTA, one grounded resistor and two grounded capacitors, has eight different forms, the type B filter, which employ one CCCCTA, two grounded capacitors and a second-generation current-controlled conveyor (CCCII) or an second-generation inverting current-controlled conveyor (ICCCII) or an operational trans-conductance amplifier (OTA), has 64 different forms and the type C filter employing one CCCCTA and two grounded capacitors has eight different forms. In all, 80 voltage-mode/current-mode T-T filter circuits are obtained. Because of using canonic number components, the circuits are highly desirable from the viewpoint of IC fabrication and their parameters can be electronically tuned through tuning bias currents of CCCCTAs. The hand analysis and computer simulation results have been provided to support the synthesis method.     

Synthesis of multivariate stationary series with prescribed marginal distributions and covariance using circulant matrix embedding

The problem of synthesizing multivariate stationary series Y[n]=(Y₁[n],…,Y_P[n])^T, n∈Z, with prescribed non-Gaussian marginal distributions, and a targeted covariance structure, is addressed. The focus is on constructions based on a memoryless transformation Y_p[n]=f_p(X_p[n]) of a multivariate stationary Gaussian series X[n]=(X₁[n],…,X_P[n])^T. The mapping between the targeted covariance and that of the Gaussian series is expressed via Hermite expansions. The various choices of the transforms f_p for a prescribed marginal distribution are discussed in a comprehensive manner. The interplay between the targeted marginal distributions, the choice of the transforms f_p, and on the resulting reachability of the targeted covariance, is discussed theoretically and illustrated on examples. Also, an original practical procedure warranting positive definiteness for the transformed covariance at the price of approximating the targeted covariance is proposed, based on a simple and natural modification of the popular circulant matrix embedding technique. The applications of the proposed methodology are also discussed in the context of network traffic modeling. Matlab codes implementing the proposed synthesis procedure are publicly available at http://www.hermir.org.     

一种基于自举电路的可调恒压恒流源设计

介绍了一种基于自举电路的可调恒压恒流源的设计.解决了使用普通运算放大器调整较高输出电压的问题.在输出电压在较大范围变化时,通过自举的方法保证运算放大器的供电电压不变,并且能够对输出电压和电流进行有效地调整,实现了0~30V的电压输出和0~1A的电流输出.     

Systematic Synthesis of Compressive VDTA-Based T-T Filter with Orthogonal Control of fo and Q

Based on sixteen nullor-mirror models of the voltage differencing transconductance amplifier (VDTA) and port admittance matrices of the tow-Thomas (T-T) filter with orthogonal control between the characteristic frequency (f_o) and figure of merit (Q), two different categories of the voltage-mode and transconductance-mode T-T filters are synthesized by the means of the nodal admittance matrix (NAM) expansion method. The category A filter that employs two compressive VDTAs and two grounded capacitors includes four structures, and the category B filter that uses two compressive VDTAs, two grounded capacitors, and one grounded resistor, also includes four structures. These circuits are suitable for integrated circuit manufacture, and their parameters f_o and Q can be orthogonally adjusted with varying the bias currents of VDTAs. After the paper and pencil test is completed, the computer analyses, including alternating current (AC), parameter sweep, Monte Carlo (MC), and noise analyses, are performed to support the synthesis approach.