Temporal Instabilities in Traveling-Wave Parametric Amplifiers (Correspondence)

The basic traveling-wave parametric amplifier (TWPA) [1]-[3], as here defined, consists of an all-pass uniform transmissionline structure in which the distributed circuit elements are modulated in time and space by a progressive pumping wave. TWPA's, in general, have aroused great interest due to the possibilities of wide-band amplification, as predicted by coupled mode theory [2]-[4]. It is the purpose of this communication to show that temporal instabilities exists on the basic TWPA (or its dual [1]) when the frequency relations are of the negative-resistance type (the inverting modulator of manley and rowe [6]). it is found, from the exact solution for time harmonic waves existing on this line, that under these conditions waves growing in time are present, rather than waves growing in distance along the line.     

A generalized active compensated noninverting VCVS with reduced phase error and wide bandwidth

A general circuit for the active compensation of the op-amp noninverting VCVS is given. The circuit has the same topology as the Geiger maximally flat magnitude circuit [1]. The proposed design has the advantages of a smaller phase error and a larger bandwidth than the design in [1]. Moreover, it relaxes the restriction on the relizable dc gain obtained using the design in [1]. The proposed modified design includes the recently described, active compensated, voltage follower [2] as a special case.     

Novel first order all-pass sections using a single CCIII

Two novel first order voltage-mode all-pass sections using a single third generation current conveyor (CCIII) are given. In addition the first circuit uses three resistors and one capacitor and the second circuit which is derived from the first circuit uses two resistors and one capacitor. A current-mode first order all-pass section requiring one capacitor and one resistor is also proposed. SPICE simulation results are incorporated to verify the theory.     

Active all-pass filter using differential amplifier

The relationship between a recently described active all-pass filter using a differential amplifier and one described in an earlier paper is discussed. A method of using either circuit to produce an all-pass function of any degree is also indicated.     

Derivation of low-power first-order low-pass,high-pass and all-pass filters

In this letter, a new voltage-mode (VM) configuration for providing low-power and simultaneous realization of first-order low-pass, high-pass and all-pass filters is presented. The output of the all-pass filter is taken differentially. The proposed circuit contains low number of components, i.e., only two NMOS transistors, a floating battery, a grounded capacitor and a floating resistor. Adding two NMOS transistors to the proposed circuit it is modified as an all-pass filter with a single-ended output. The main advantage of the presented circuits in comparison with other counterparts is their extremely low power dissipation. Moreover, the floating resistor can be replaced with an additional NMOS transistor in triode region to provide electronic tunability. Simulation results using SPICE program are given to demonstrate the performance of the proposed circuit.     

Unity direct chain with feedback series impedance based innovative negative group delay circuit

An innovative negative group delay (NGD) circuit theory on unity direct chain (UDC) topology is developed in this paper. The NGD UDC cells are based on the operational amplifier adder with feedback series impedance. Innovative topologies of high-pass NGD UDC cell composed of RL-series network, all-pass RC-parallel network and low-pass RC-series network are identified. It is a first time that all-pass NGD original topologies are defined. NGD analyses and synthesis methods of each NGD UDC cells are provided. The UDC cell based NGD functions are validated with SPICE simulations. The proofs-of-concept (POC) of UDCs behave as all-pass and low-pass NGD functions with group delay equal to −1 ms at very low frequencies. The low-pass NGD cut-off frequency is 424 Hz. The high pass NGD circuit generates −1 µs at the optimal NGD frequency of about 5.15 kHz. Further analysis of the operational amplifier gain and bandwidth effects is performed. The operational amplifier gain affects significantly the NGD level and bandwidth for the all considered UDC cells. Nevertheless, only the RC-parallel feedback based UDC cell is particularly sensitive to the operational bandwidth.     

Active all-pass filter using a differential operational amplifier

A circuit is presented for a first-order active all-pass filter using a single differential operational amplifier. The form of the transfer function is T(p) = (1 ? p)/(1 + p).     

差分式CMOS多功能电流模式滤波器

本文提出多端输出的CMOS电流加法器，在此基础上提出了新型差分式CMOS多功能电流模式滤波器的信号流图和电路。该滤波电路能同时产生二阶低通、带通、高通输出，并通过适当的连接能产生二阶带阻和全通滤波输出。对提出的滤波器截止频率为1MHz的电路进行了计算机PSPICE仿真。     

A Novel CMOS-Based Voltage-Mode First-Order Phase Shifter Employing a Grounded Capacitor

In this paper, a voltage-mode (VM) topology for providing first-order all-pass filter responses is suggested. The proposed circuit is composed of a smaller number of components when compared to earlier ones, as it employs only three CMOS transistors, a grounded capacitor which is advantageous in integrated circuit (IC) processes, and two resistors. Computer simulation results, using the SPICE program, are given to exhibit the performance. A second-order low-pass filter employing only grounded capacitors which are canonical in number is given as one of the applications of the presented non-inverting first-order all-pass filter topology.     

Novel Transimpedance Type First-Order All-Pass Filter Using Single Otra

A novel transimpedance-mode first-order all-pass filter configuration is proposed. It uses a single operational transresistance amplifier (OTRA) and few passive components. The proposed circuit is structurally all-pass that does not impose any component matching condition. The proposed circuit is insensitive to parasitic input capacitances and input resistances due to the internally grounded input terminals of the OTRA. It provides an alternative realization of phase equalizers for analog signal processing applications by providing also current-to-voltage conversion. The theoretical results are verified with PSPICE simulations using a CMOS realization of OTRA.     

基于OTA的通用双二阶滤波器设计

在跨导运算放大器（OTA,Operational Transconductance Amplifier）器件特性的基础上,提出了一种采用OTA构成的电压模式三输入单输出通用双二阶滤波电路,该电路由4个OTA、2个电容构成。通过选择不同的输入端口,它可以实现二阶低通、带通、高通、陷波、全通5种滤波功能,通过分析该电路的传输函数可知,该电路的灵敏度低,对该电路用PSPICE进行了仿真,仿真结果表明该电路设计正确。     

Active all-pass network

A simple method of designing an all-pass network is presented. Final realisation incorporates a single nonideal current-controlled current source, which in most applications can be replaced by a single-transistor circuit.     

Supplementary all-pass sections with reduced number of passive elements using a single current conveyor

Four new configurations realizing current conveyor-based first-order all-pass filters are proposed. Using these configurations two types of first-order voltage-mode allpass filter can be realized. The circuits employ a single positive type secondgeneration current conveyor (CCII+) and only three passive components. For each topology only a simple component matching constraint is required. To illustrate the design possibilities provided by the introduced circuits an oscillator circuit consisting of the proposed all-pass filters is constructed and experimentally tested.     

Simple first order all-pass section using a single CCII

A novel first order all-pass section using a single second generation current conveyor is given. In addition the circuit uses two resistors and only one capacitor. The circuit is also realized with a translinear conveyor. The latter circuit uses only one external resistor and a capacitor. The proposed circuits are verified using PSPICE with attractive results.     

Equalization of Waveguide Delay Distortion

Microwave all-pass circuits, consisting of reactive networks used in conjunction with wide-band circulators or couplers, are described. An extremely useful all-pass circuit for minimizing phase distortion results when the restive network is a linear taper extending beyond cutoff. The delay characteristics of this circuit are well suited to the correction of the dispersive characteristics of TE or TM mode waveguides. Design formulas have been derived for the parameters of the tapers and a set of design curves is presented. The use of composite tapered sections and the use of tapers in conjunction with other equalizing circuits are described. Experimental results have been obtained for the phase of the reflection factor of a linear taper. Close agreement was observed between the results predicted by theory and the experimental data. Typical examples demonstrate that the time-delay variation of a length of uniform waveguide can be substantially reduced by linearly tapered waveguide equalizers.     

Current-mode biquad using OTAs and CF

A novel current-mode biquad using operational transconductance amplifiers (OTAs) and current follower (CF) is presented. The circuit can realise lowpass, bandpass, highpass, band-stop and all-pass transfer functions without any circuit matching conditions. The circuit parameters can also be tuned independently by the transconductance gains of the OTAs. The proposed biquad enjoys very low sensitivities with respect to the circuit elements.     

射频板条CO2激光器放电特性的数值研究

给出了射频板条ＣＯ２激光器α型放电集总参数等电电路模型。计算了谐振放电状态下集总参数的电路方程得到了沿激光器电极长度方向上的电压幅度和相位的分布,沿电极最小的相对电压幅度起伏约为１．２７％,由模型推导出用宏观测量参数表示的ＲＬＰ和Ｅ／Ｐｇａｓ的计算公式,不同于ＲａｌｆＭａｌｚ的结果,建立了射频板条ＣＯ２激光器的实验装置,获得了均匀射频放电和ＣＯ２激光。     

基于MOCCII多功能电流模式滤波器

本文提出一种新型基于MOCCII多功能电流模式二阶滤波器电路,该滤波器电路仅由2个MOCCII及4个RC元件构成,无需元件匹配就能同时实现低通、带通、高通、带阻及全通滤波输出.该电路所有的RC元件均接地,且有很低的灵敏度.文中对滤波器的非理想特性进行了分析.最后对提出的电路进行了计算机仿真.     

Cascaded Network Optimization Program

A user-oriented computer program package is presented that will analyze and optimize certain cascaded linear time-invariant electrical networks such as microwave filters and all-pass networks. The program is organized in such a way that future additions or deletions of performance specifications, constraints, optimization methods, and circuit elements are readily implemented. Presently, a variety of two-port lumped and distributed elements, all-pass C-type sections and all-pass D-type sections can be treated as fixed or variable between upper and lower bounds on the parameters. Adjoint network sensitivity formulas are incorporated. The Fletcher-Powell or Fletcher optimization methods can be called to optimize in the least pth sense of Bandler and Charalambous an objective function incorporating simultaneously, at the user's discretion, input reflection coefficient, insertion loss, group delay, and the parameter constraints (if any). The program is particularly flexible in the way in which response specifications are handled at any number of, in general, overlapping frequency bands. The package, which is written in Fortran IV, has been tested on a CDC 6400 digital computer.     

Novel current-mode active-only biquad with loss-less and lossy integrators

This paper presents a realization of a current-mode active-only biquad with a two-integrator loop structure. The proposed circuit is constructed solely with operational amplifiers (OAs) and operational transconductance amplifiers (OTAs). The circuit can realize low-pass, band-pass, high-pass, band-stop and all-pass transfer functions, and the circuit characteristics can be electronically tuned by adjusting the transconductance gains of the OTAs. An example is given together with simulated results by PSPICE. The circuit configuration is very suitable for implementation in both bipolar and CMOS technologies.