China
Africa
Explore chapters and articles related to this topic
Mixer Sub-Systems
Published in Douglas Self, Small Signal Audio Design, 2020
The oscillator is based on the classic Wien bridge configuration, with the oscillation frequency controlled by R8, R9, C1 and R5, R6, C2. When running at 1 kHz R8, R9, and R5, R6 are in circuit. For 10 kHz, SW1 is pressed, and R5 and R9 are now shorted out, raising the operating frequency. The level control loop operation is as follows: when SW2 is pressed, the short circuit across R1 in the negative feedback loop R1, R2 which prevents oscillation is removed and the amplitude of oscillation ramps up. When it reaches the desired level, Zener diode D1 begins to conduct on positive peaks and turns on the common-base transistor Q1 (D1 also conducts on negative half-cycles, but Q1 does not respond and is protected from reverse bias by clamp D2). The collector current of Q1 charges C3 and Q2 turns on, pulling down the gate of JFET Q3 and increasing its channel resistance, thus increasing the amount of negative feedback through R1, R2 and regulating the level. Q3 is a J112 FET, a type that is optimised for voltage-controlled resistance (VCR) operation. The network R3, R4 not only acts as the collector load for Q2 but also feeds half the Vds of Q3 to its own gate; this is a classic method of reducing even-order distortion in JFETs and is dealt with in more detail in Chapter 24. C3 and R10 set the time-constant of the control loop, and their values have a strong effect on oscillator distortion. Q1 and Q2 can be any high-beta transistor types.
Dynamic response analysis of fractional order RLCα circuit and its order dependent oscillation criterion
Published in Applied Mathematics in Science and Engineering, 2023
Fractional order oscillator equation is analysed in [31–34]. In the field of electronics, oscillators have important applications in signal generation. In recent years, more and more theory and design of fractional order oscillators is provided. The topologies of the Wien bridge oscillator family is analysed in [35], while [36] provides four practical sinusoidal oscillators. The fractional-order differential equations design of sinusoidal oscillators is reported in [37]. The Barhkausen condition for fractional-order oscillate systems and fractional generalization of some famous integer-order sinusoidal oscillators is shown in [38]. Analysis of the fractional order operational transresistance amplifiers based oscillator is provided in [39] and some fractional order sinusoidal oscillators is designed in [40,41].
A Robust Two-axis Tilt Angle Sensor Based on Air/Liquid Two-phase Dielectric Capacitive Sensing Structure
Published in IETE Journal of Research, 2020
Ha Tran Thi Thuy, Tiep Dang Dinh, Tuan Vu Quoc, Thinh Pham Quoc, Masahiro Aoyagi, My Bui Ngoc, Van Thanh Dau, Tung Thanh Bui
The block diagram of the electronic circuit is given in Figure 9. A 170-kHz sine signal generator is connected to the excitation electrode. The sine generator circuit is a Wien bridge oscillator using an operation amplifier (TL084). The frequency of the oscillator is controlled by resistor R and capacitor C; output amplitude is adjusted by resistors R1 and R2. Because the voltage on sensing electrodes changes with their corresponding capacitance, roll and pitch angles can be monitored by measuring the amplitude of the differential voltage pair (VC1 − VC2) and (VC3 − VC4), respectively.
Bi-Stability in an Improved Memristor-Based Third-Order Wien-Bridge Oscillator
Published in IETE Technical Review, 2018
Han Bao, Ning Wang, Huagan Wu, Zhe Song, Bocheng Bao
With the equivalent circuit in Figure 1, an improved memristor emulator-based Wien-bridge oscillator is easily constructed, as shown in Figure 3, which is conveniently achieved by substituting the parallel resistor in a classical second-order Wien-bridge oscillator with the proposed emulator in Figure 1. The memristive Wien-bridge oscillator is third-order and inductor-free. Compared the memristive Wien-bridge oscillator in Figure 3 with the memristive band pass filter chaotic circuit in [14], there are same number and types of electronic components but different circuit topologies.