基于单个VDTA浮地回转器的系统综合法

为了得到单个VDTA浮地回转器,首先给出了VDTA的16个奇异模型,再根据节点导纳矩阵扩展法,系统综合了基于电压差分跨导放大器(VDTA)的浮地回转器,该回转器使用1个VDTA和一个接地电容,而且容易集成。通过调节的VDTA偏置电流,电路的参数能电控调节。最后,为了证实导出电路的可实现性,利用回转器构造了一个二阶通用滤波器,其极点频率fo=159 k Hz,品质因数Q=1。MULTISIM仿真结果与理论一致。

基于VDTAs接地回转器的系统综合法

基于实现电压差分跨导放大器(VDTA)的接地回转器目的,采用节点导纳矩阵扩展法(括号符号法),系统综合了2个基于VDTA接地回转器。所综合的电路仅仅使用一个VDTA,通过调节VDTA的偏置电流,电路的参数能电控调节。为证实电路工作的可靠性,基于该回转器之一,利用元件替换法,设计了电流模式三阶巴特沃斯高通滤波器,其极点频率为100 k Hz,通带增益为0.5,结合计算机仿真结果,得出所设计的电路正确有效。

Systematic Synthesis of Compressive VDTA-Based T-T Filter with Orthogonal Control of f_o 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_0) 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_0 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.

Electronically Controllable Fully-Uncoupled Explicit Current-Mode Quadrature Oscillator Using VDTAs and Grounded Capacitors

An electronically controllable fully uncoupled explicit current-mode quadrature oscillator employing Voltage Differencing Transconductance Amplifiers (VDTAs) as active elements has been presented. The proposed configuration employs two VDTAs along with grounded capacitors and offers the following advantageous features 1) fully and electronically independent control of condition of oscillation (CO) and frequency of oscillation (FO);2) explicit current-mode quadrature oscillations;and 3) low active and passive sensitivities. The workability of proposed configuration has been demonstrated by PSPICE simulations with TSMC CMOS 0.18 μm process parameters.

VDTA Based Electronically Tunable Voltage-Mode and Trans-Admittance Biquad Filter

In this paper, a biquad filter configuration based on two voltage differencing transconductance amplifiers (VDTAs) as newly active elements and only two capacitors as passive elements is proposed which can realize voltage-mode low pass (LP), band pass (BP), high pass (HP), band reject (BR) and all pass (AP) filtering responses using three voltage inputs. Simultaneously, the same configuration can also be used to obtain LP, BP and HP filtering responses in transadmittance-mode. The proposed biquad is capable of providing electronic control of quality factor independent of pole frequency through single transconductance parameter (biasing current). It also offers the advantage of low active and passive sensitivity. To support the theoretical analysis, the PSPICE simulation of the proposed circuit is done using 0.18 μm CMOS technology from TSMC.

Grounded and Floating Inductance Simulation Circuits Using VDTAs

New electronically-controllable lossless grounded and floating inductance simulation circuits have been proposed employing Voltage Differencing Transconductance Amplifiers (VDTA). The proposed grounded inductance (GI) circuit employs a single VDTA and one grounded capacitor whereas the floating inductance (FI) circuit employs two VDTAs and one grounded capacitor. The workability of the new circuits has been verified using SPICE simulation with TSMC CMOS 0.18 μm process parameters.

New Voltage Mode Sinusoidal Oscillator Using Voltage Differencing Transconductance Amplifiers (VDTAs)

The purpose of this paper is to introduce a new electronically controlled voltage mode sinusoidal oscillator (VMSO) using Voltage Differencing Transconductance Amplifiers (VDTA). The proposed circuit provides electronic control of ω0 and independent condition of oscillation (CO). It is found that the oscillator works very satisfactorily and pure sinusoidal waveforms are available at the outputs. The PSPICE simulation confirms the theoretical results. The proposed oscillator circuit employs only two VDTAs, along with two grounded capacitor and single grounded resistor. The circuit exhibits low active and passive sensitivities for ω0. Simulation results are obtained by using PSPICE software with TSMC CMOS 0.18 um process parameters.

Synthesis for Current-Mode Sallen-Key Filter Using VDTAs

In this work, an original Sallen-Key second-order low-pass filter is first turned into a current-mode one by means of the adjoint network theorem. Two nodal admittance matrices(NAM) of the filter are then educed. Furthermore, these two matrices are expanded through NAM expansion approach, generating one current-mode Sallen-Key filter, which uses two compact voltage differential trans-conductance amplifiers(VDTAs) and two grounded capacitors, implements not only one low-pass transfer function but two band-pass transfer functions, and provides the non-interrelated control between the natural frequency and quality factor. As an example of the synthesized filter, a second-order VDTA filter with fo=1 MHz, Q=1, HLP=-HBP1=HBP2=1 is designed. The used synthesis approach has been confirmed with the help of circuit and computer analysis.

一种新的电压模式正弦波振荡器设计

设计一种新的使用电压差分跨导放大器(VDTA)构建的电子控制电压模式正弦波振荡器(VMSO),电路可对振荡频率ω0和振荡条件进行独立电子控制。通过PSPICE仿真,验证电路的基本理论结果,由结果可知,振荡器能够输出理想的正弦波波形.