单片CDCTA-C低功耗电控调谐双模式三阶正交振荡器的设计

针对振荡器功耗大和振荡频率低的问题,提出了一种基于电流差分级联跨导放大器的三阶正交振荡电路.该电路仅使用一个电流差分级联跨导放大器和三个接地无源电容,可以同时产生两组等幅正交电流信号和一组等幅正交电压信号.电路结构简单,功耗低至1.8mW,最大灵敏度绝对值仅0.5,振荡频率可达10MHz数量级,而且振荡条件和震荡频率可相互独立地电控调谐.计算机模拟和流片芯片测试结果验证了理论分析的正确性.     

基于单个CDCTA的低压电控调谐电流模式多相位正弦振荡器的设计

提出了一种全新的电流模式多相位正弦振荡器电路。该电路仅使用一个电流差分级联跨导放大器(CDCTA)和接地无源元件,能产生n(n为奇或偶)个等相位差的电流信号,电路结构简单、工作电压低、输出阻抗高、振荡频率高,而且振荡条件和振荡频率独立可调。计算机CADENCE软件仿真和流片测试结果验证了理论分析的正确性。     

基于CDCTA和MOCCII的低功耗电流模式n阶滤波器

提出了一种电流模式多输入单输出的n阶滤波器。该电路包括一个电流差分级联跨导放大器(CDCTA)、一个多输出第二代电流传输器(MOCCII)和若干接地电容。无需改变电路内部的结构和器件数目,仅通过选择合适的输入电流信号就可实现任意阶的高通、低通、带通、带阻等滤波功能。该滤波器结构简单,输出阻抗高,易于集成,频带宽,功耗低,滤波性能优越。基于TSMC 0.18 μm CMOS工艺,采用Pspice对电路进行了仿真,结果证明了该滤波器理论分析的正确性。     

基于MO-CDTA的电控调谐多功能电流模式二阶滤波器/振荡器

描述了一个基于多输出电流差分跨导放大器(MO-CDTA)的多功能电流模式二阶电路.该电路仅使用四个MO-CDTA和两个接地电容,能同时和分别实现高通、带通和低通电流传输函数,电路的极点频率和品质因素能独立地被电控调节;电路也能被修饰成一个电流控制的正弦振荡器.计算机仿真表明电路正确有效.     

最少元件MO-CDTA通用二阶滤波器和振荡器

提出了一个多输出电流差分跨导放大器(MO-CDTA),并利用它设计了一个电流模式二阶电路.该电路仅使用2个MO-CDTA和两个接地电容,能同时和分别实现高通、带通和低通电流传输函数,电路的极点频率和品质因数能独立地电控调谐.电路也能被修饰成一个电流控制的正弦振荡器.计算机仿真表明,设计的电路正确有效.     

基于电流模施密特触发器的OTA—C张驰振荡器及其PSPICE仿真研究

提出了基于电流模施密特触发器的OTA-C张驰振荡器。该电路的振荡信号周期可由接地可容线性改变,而频率则与OTA的跨导成正比。经PSPICE仿真模拟,其结果与理论计算值一致。     

一种低功耗快速起振晶体振荡器

基于CSMC0.5μm40VBCD工艺,设计了一种32.768kHz的晶体振荡器电路。通过Matlab分析振荡条件,以指导电路设计;通过自动增益控制环路,使振荡器的起振时间低至206ms;由微电流的跨导放大器实现了集成电路中的大电阻,用在反馈电阻和滤波器中;环路稳定后,振荡器核心电路的电流仅为195nA,同时,该电路还提供占空比为46%的方波输出。     

基于电流模施密特触发器的OTA-C张弛振荡器及其PSPICE仿真研究

提出了基于电流模施密特触发器的OTA—C张弛振荡器。该电路的振荡信号周期可由接地电容线性改变,而频率则与OTA的跨导成正比。经PSPICE仿真模拟,其结果与理论计算值一致。     

基于文氏桥振荡器的CCCⅡ带通滤波器

为了得到一个最简单、最经济的电流模式高Q带通滤波器,我们根据传统的文氏桥振荡器和伴随网络理论,设计了一个电流模式/跨导模式的CCCⅡ带通滤波器。通过调整CCCⅡ的偏置电流,电路的极点频率和品质因数能够被独立地电调谐,当满足IB3=2IB4,电路还能产生正弦振荡。由于电路使用4个CCCⅡ和2个接地电容,因此电路适宜集成。计算机仿真结果表明设计方法正确。     

一种基于CCⅡ＋和接地RC的新型振荡器

提出了由一个同相第二代电流传输器，两个接地电容器和两个接地电阻构成的正弦振荡器，运用负振荡器方法分析了该电路，得出了振荡条件和振荡频率，给出了电路的实验结果。该电路结构简单，且无源元件全部接地，便于集成。     

Current‐mode quadrature oscillator using current differencing transconductance amplifiers

This article presents a new electronically tunable single‐element‐controlled current‐mode quadrature sinusoidal oscillator circuit using current differencing transconductance amplifiers (CDTAs). The proposed oscillator is consisted of two CDTAs, two grounded capacitors and one grounded resistor, which is beneficial to monolithic integrated circuit implementation both in CMOS and bipolar technologies. The condition of oscillation and the frequency of oscillation are independently controllable. The frequency of oscillation can also be electronically controlled by adjusting the bias current of CDTA. The circuit provides four quadrature current outputs and two quadrature voltage outputs. The current output terminals possess high impedance level. PSPICE simulation results are used to verify the performance of the proposed circuit implemented at the transistor level. The measurement results support the computer simulations.     

A systematic realization of third-order quadrature oscillator with controllable amplitude

A systematic realization of third-order quadrature oscillator using a voltage-mode non-inverting lowpass filter and a voltage-mode inverting lossless feedback integrator is presented in this paper. The proposed circuit consists of two multiple-output differential voltage current conveyor transconductance amplifiers (MO-DVCCTAs), two grounded resistors and three grounded capacitors. The new circuit provides three quadrature voltage outputs, two high-impedance quadrature current outputs, and one high-impedance current output with controllable amplitude, simultaneously. When the input bias current of the first MO-DVCCTA is a modulating signal, the circuit can generate amplitude modulation or amplitude shift keying signals. The condition of oscillation and the frequency of oscillation can be controlled independently through grounded resistors. The proposed circuit only uses grounded capacitors and grounded resistors, which can be easily implemented as an integrated circuit. The experimental results and H-Spice simulation results are given to confirm the theoretical analysis.     

Quadrature Oscillators with Grounded Capacitors and Resistors Using FDCCIIs

Two current‐mode and/or voltage‐mode quadrature oscillator circuits each using one fully‐differential second‐generation current conveyor (FDCCII), two grounded capacitors, and two (or three) grounded resistors are presented. In the proposed circuits, the current‐mode quadrature signals have the advantage of high‐output impedance. The oscillation conditions and oscillation frequencies are orthogonally (or independently) controllable. The current‐mode and voltage‐mode quadrature signals can be simultaneously obtained from the second proposed circuit. The use of only grounded capacitors and resistors makes the proposed circuits ideal for integrated circuit implementation. Simulation results are also included.     

Cascadable Current-Mode Biquad Filter and Quadrature Oscillator Using DO-CCCIIs and OTA

This article introduces a circuit which can function both as a quadrature oscillator and as a universal biquad filter (lowpass, highpass, bandpass). When the circuit functions as a universal biquad filter, the quality factor and pole frequency can be tuned orthogonally via the input bias currents. When it functions as a quadrature oscillator, the oscillation condition and oscillation frequency can be adjusted independently by the input bias currents. The proposed circuit can work as either a quadrature oscillator or a biquad filter without changing the circuit topology. The amplitude of the proposed oscillator can be independently controlled via the input bias currents. The proposed oscillator can be applied to provide amplitude modulated/amplitude shift keyed signals with the above-mentioned major advantages. The circuit is very simple, consisting of four dual-output second generation current controlled current conveyors (DO-CCCIIs), one operational transconductance amplifier (OTA), and two grounded capacitors. Without any external resistors and using only grounded elements, this circuit is therefore suitable for IC architecture. PSPICE simulation results are depicted here, and the given results agree well with the theoretical analysis. The power consumption is approximately 7.32 mW at ±2.5 V supply voltages.     

Single-resistance-controlled quadrature oscillator using current differencing buffered amplifiers

A single-resistance-controlled quadrature oscillator circuit using current differencing buffered amplifiers (CDBAs) as active components is proposed. The proposed circuit is realised through the employment of two CDBAs, three resistors and two grounded capacitors. Outputs of two sinusoidal with 90° phase difference are available. The oscillation condition and the oscillation frequency of the proposed quadrature oscillator can be controlled independently by a single resistor. In comparison with the previously reported circuits, the proposed configuration considerably reduces the number of passive elements.     

Quadrature oscillators using CCIIs

Three third-order quadrature oscillators are proposed. Outputs of two sinusoids with 90° phase difference are available in each quadrature oscillator circuit. The oscillation condition and oscillation frequency of each proposed quadrature oscillator are orthogonal controllable. All proposed circuits employ only grounded capacitors. The use of only grounded capacitors is ideal for integration. Experimental results are included to confirm the theoretical analysis.     

Novel voltage/current-mode quadrature oscillator using current differencing transconductance amplifier

This letter proposes a new realization of voltage/current-mode (CM) quadrature oscillator (QO) using Current Differencing Transconductance Amplifier (CDTA) as the active element. The proposed circuit employs canonic number of components, namely two CDTAs, one resistor and two grounded capacitors. The oscillator is capable of providing two explicit quadrature current outputs and two quadrature voltage outputs. Moreover, the circuit enjoys the advantage of independent control of condition of oscillation (CO) and frequency of oscillation (FO). The non-ideal analysis and sensitivity study of the circuit has been carried out and the circuit exhibits a good sensitivity performance. B2SPICE simulation results are included that validate the working of the circuit.     

New canonic lossy inductor using a single CDBA and its application

A new lossy inductor (parallel R-L type) using single current differencing buffered amplifier (CDBA) is presented, which employs only two resistors and a grounded capacitor. The proposed lossy inductor is shown to be useful in realizing an oscillator circuit, which provides quadrature voltage outputs using only two CDBAs, three resistors and two grounded capacitors and offers independent control on condition of oscillation and frequency of oscillation up to a frequency of 61 MHz. Detailed non-ideal analysis including single-pole model for voltage and current gain has also been carried out. SPICE simulation results and experimental results based upon the CDBA constructed from commercially available IC AD844 have been included which confirm the practical workability of the proposed lossy inductor and quadrature oscillator circuit.