On a multivibrator that employs a fractional capacitor

The simple free running multivibrator built around a single fractional capacitor is examined in this letter. Equations for the oscillation frequency of the multivibrator are derived taking into account the positive feedback factor around the multivibrator. We show that the use of the fractional capacitance allows the multivibrator to have very high frequencies of oscillation for reasonable time constants used. PSPICE simulation and experimental results demonstrate the analysis with an approximation to a fractional capacitor that yields a result, which is at least 1000 times in frequency compared to if a normal capacitor of the same value was employed.     

Analysis of a source-coupled MOS multivibrator with resistive drain loads

The determinant of the system of nodal equations of a source-coupled MOS multivibrator is calculated. Equating this determinant to zero, one can obtain the condition of transition from one quasistable state to another. This condition is used to calculate the currents in the multivibrator transistors at the instant of transition. Then the voltage amplitude at the coupling capacitor is calculated and the oscillation frequency is found. The oscillation frequency in this multivibrator depends on the value of currents supplied to the circuit and the power supply voltage. The results were verified experimentally.     

基于可编程控制器多谐振荡器的设计与分析

在数字电路中,常常需要一种不需外加触发脉冲就能够产生具有一定频率和幅度的矩形波电路,特别是要求频率和占空比可调的这种电路,它就是多谐振荡器.文章采用可编程控制器来设计完成该功能,它具有设计简单,完成方便,频率和占空比用软件就可调试,不需要对电路重新组装的特点.     

射频连续波对多谐振荡器的干扰研究

在GTEM室中用射频连续波对某导弹装备上的一块数字控制电路进行电磁辐照实验,在一定的场强下,产生控制信号的自激多谐振荡器受到了电磁干扰,主要表现为产生的方波控制信号占空比增大。分析了多谐振荡器受干扰的机理,用电路仿真软件对多谐振荡器受到的干扰进行了模拟,验证了对干扰机理的分析。     

Stability of oscillation frequency of ECL-based multivibrator

The stability (with temperature and power supply voltage variations) of the oscillation frequency f₀ of an ECL-based multivibrator is considered. This circuit is a non-saturated multivibrator. Its operation is revised and an exact expression for calculation of f₀ is obtained. Then the temperature coefficient and sensitivity to the power supply voltage are derived. The results were verified experimentally. Some recommendations on the choice of the external timing components are given.     

新型负阻HBT构成的非稳多谐振荡器研究

报道了由超薄基区负阻异质结双极晶体管(UTBNDRHBT)构成的非稳多谐振荡器,具有高速、可调控等优点。对其电压控制脉冲频率调制效应进行了实验研究,观察到了仅由基极电压(V_(BE))即可控制脉冲间距和脉冲宽度;对实验现象给出了相应分析,并指出了此电路的应用前景。     

Fundamental performance limitations for transit-time devices: A zeroth-order analysis

A current-controlled multivibrator using operational transconductance amplifiers (OTAs) is proposed and the circuit operation is described. The frequency of oscillations ?_o is calculated (both bipolar and MOS OTAs are treated). The circuit allows operation with a low voltage power supply. An example describes the experimental results for the multivibrator realized with CA3080 OTA integrated circuits. Linear control of ?_o over a two decade range (500 Hz–50 kHz) is obtained with the minimum rated power supply voltage of ±2 V.     

门电路环形振荡器仿真研究

在测量门电路的传输延迟时间时,通常用门电路环形振荡器,但门电路环形振荡器振荡频率较高,对实验仪器设备的要求也较高,用仿真实验的方法有直观明了的优点,所以在数字电路教学中常用仿真的方法来进行实验.然而,在用仿真方法进行实验分析时,实验结果和实物实验或理论分析会存在一些差异.分别用EWB的2种版本仿真软件EWB 5和Multisim 9对门电路环形振荡器进行仿真,分析出现差异的原因,指出在用仿真方法进行数字电路仿真分析和设计时要注意的问题.     

单运放多谐振荡器

分析了一种由单运算放大器构成、电路中包含二个充放电回路的多谐振荡电路，并对振荡信号的波形和输出信号的振荡频率进行了讨论，得到了计算公式；对振荡电路进行了实验分析，测试结果说明了理论分析的正确性。     

A Bistable Multivibrator as a Phase and Frequency Detector

It is very important to obtain a good noise-limiting performance and wide catching region by phase locked oscillators. In order to obtain these characteristics, a phase detector must operate simultaneously as a frequency detector. In this report it is shown how a bistable multivibrator modified for phase detector operation operates as a frequency detector as well.     

A quartz multivibrator using two regenerative switches

A new quartz multivibrator having a 10-ns transition time is described. The frequency dependence on the supply voltage is less than 10^-6per volt. The output voltage is nearly equal to the supply voltage. The circuit can be heavily loaded.     

555定时器功能与应用特点

归纳了555定时器的功能,给出了一种易于记忆的简化模型,同时就其构成的无稳态触发器、单稳态触发器及双稳态触发器等应用电路的特点进行了探讨.     

Improved crosscoupled multivibrator controllable in frequency over a wide range

An improved crosscoupled multivibrator is described which can be continuously varied in frequency over a wide range (considerably in excess of 100 to 1 with an upper frequency of 10 MHz). The circuit can operate from a 5 V supply line, and therefore it is ideal as a clock generator for logic elements because a common power supply can be used.     

Current-controlled oscillator

A relaxation oscillator whose frequency is linearly related to an input control current is described. The circuit configuration is based on the emitter-coupled astable multivibrator. The linear frequency variation is obtained by incorporating a discriminator circuit and high-transconductance elements into the oscillator circuit. Experimental results obtained from a circuit constructed from monolithic transistor arrays indicate that frequency variation over two decades, with a linearity better than 0.1%, can be obtained.     

A novel CMOS multivibrator

The paper describes a CMOS multivibrator using a differential pair with positive feedback via a current mirror and a diode-connected NMOS transistor; the output voltage is taken at this transistor. The timing capacitor is charged by a current source and discharged by the differential pair tail current. During capacitor charging the tail current is steered into the current mirror. The mirror output current is applied to a diode-connected transistor and creates the HIGH level of the output voltage. During discharging the diode connected transistor obtains a small current (from another current source) which determines the LOW level of the output voltage. The capacitive loading and frequency limit are investigated. The design procedure is given. The body effect does not affect the circuit performance. This allows to reduce the multivibrator area.     

A 4.3-GHz VCO with 2-GHz tuning range and low phase noise

A voltage-controlled oscillator (VCO) based on double cross-coupled multivibrator structure with a center frequency of 4.3 GHz and a tuning range of 2 GHz has been designed and implemented in standard 0.35 μm BiCMOS technology. The measured phase noise is 113 dBc/Hz at 600-kHz offset frequency from the carrier. The VCO draws 14.6 mA from the 2.5-V supply     

A versatile monolithic voltage-to-frequency converter

Voltage-to-frequency (V-F) conversion is achieved with high linearity (0.02 percent) using a precise multivibrator with an 80-dB dynamic range. The IC operates from a single, low-current supply and can accept millivolt signals. A unique thermometer output permits direct conversion of temperature to frequency.     

非对称式多谐振荡器的Multisim仿真

针对Multisim中器件从0输出状态开始仿真,仿真非对称式多谐振荡器工作波形不能形成振荡输出,提出了在仿真电路的输入端接入转换开关,仿真时先将转换开关接地使电路脱离系统设置的初始输出状态,再通过转换开关构成非对称式多谐振荡器,进行正常工作状态的仿真.特点是直观形象地描述了多谐振荡器的工作工程、解决了多谐振荡器工作波形无法用电子实验仪器进行分析验证的问题.     

单稳态触发器的结构及其开关级设计原理

根据单稳态触发器定时单元特性,提出了单稳态触发器的一般结构.在此基础上,运用传输电压开关理论进行了CMOS单稳态触发器的开关级设计研究,并具体设计了两个单稳态触发器.设计实例表明文中提出的方法不仅简单、有效,而且具有通用性.     

多谐振荡器的研究与仿真

分析了各种多谐振荡器的电路结构及工作原理，并利用Multisim10．0对部分电路进行了仿真，重点介绍了单稳型多谐振荡器，讨论集成单稳态触发器74121定时元件RC对暂稳态的影响以及单稳型多谐振荡器的应用。Multisim软件是一种形象化的虚拟仪器电路仿真软件，它能比较快速地模拟、分析、验证所设计电路的性能，在课堂教学中引入EDA技术，使传统教学环节与先进的仿真技术相结合，实现授课的生动性和灵活性，增强学生对基本概念的理解，激发学生的学习兴趣，培养并有效提高学生综合分析、应用及创新能力。