Frequency Response Of Circuits Research Articles

Effect of vibration frequency on tribological characteristics of vibration-assisted micro-nano machining

Experimental findings regarding the influence of vibration frequency on the machining outcomes of vibration-assisted machining (VAM) have been inconsistent. This work aims to address this issue through both experimental and theoretical analyses. The results indicate that the circuit's frequency response is the primary source of these discrepancies. When the vibration frequency is less than half the cutoff frequency, the friction force reaches a minimum while the wear volume peaks. The solution of the heat conduction equation demonstrated that the acoustic softening effect drives the softening mechanism in nanoscale VAM. Molecular dynamics (MD) simulations further elucidate the damage mechanisms during the wear process, showing that high-frequency vibrations contribute to achieving high-precision machining.

Parameter identification of transformer lumped element network model through genetic algorithm‐based gray‐box modelling technique

AbstractThe lumped element network model has been proven to be an efficient tool for the interpretation of transformer Frequency Response Analysis. However, it is challenging to obtain parameters of the model if transformer design information is unavailable. In such a case, optimisation algorithms can be used for gray‐box model parameter estimation. A methodology is developed by the authors to establish a transformer network model without winding design data, and instead, end‐to‐end open circuit Frequency Response and other terminal test results are utilised; and Genetic Algorithm is applied to approximate the unknown parameters of the model. The modelling approach developed is independent of the unit number of the network model and therefore guarantees the accuracy of optimisation. Furthermore, it can deal with transformers with a complicated winding structure such as interleaved disc type winding. Two single windings, helical and interleaved disc type, and a single‐phase 144/13 kV 60 MVA transformer are used to demonstrate the method. FRA spectra produced by the best estimated gray‐box model and the corresponding white‐box model are compared. The main features in amplitude and phase spectra are well matched, with low values of Relative Standard Deviation, for both single windings and transformer. Estimated electrical parameters show a high consistency with reference values, which are calculated based on winding design data. This validates the methodology and gives confidence to apply grey‐box modelling for FRA interpretation.

An Interleaved Segmented Spectrum Analysis: A Measurement Technique for System Frequency Response and Fault Detection.

A frequency spectrum segmentation methodology is proposed to extract the frequency response of circuits and systems with high resolution and low distortion over a wide frequency range. A high resolution is achieved by implementing a modified Dirichlet function (MDF) configured for multi-tone excitation signals. Low distortion is attained by limiting or avoiding spectral leakage and interference into the frequency spectrum of interest. The use of a window function allowed for further reduction in distortion by suppressing system-induced oscillations that can cause severe interference while acquiring signals. This proposed segmentation methodology with the MDF generates an interleaved frequency spectrum segment that can be used to measure the frequency response of the system and can be represented in a Bode and Nyquist plot. The ability to simulate and measure the frequency response of the circuit and system without expensive network analyzers provides good stability coverage for reliable fault detection and failure avoidance. The proposed methodology is validated with both simulation and hardware.

NEGATIVE RESISTANCE ACTIVE RESISTOR WITH IMPROVED LINEARITY AND FREQUENCY RESPONSE

An original active resistor circuit will be presented. The main advantages of the new proposed implementations are the improved linearity, small area consumption and improved frequency response. An original technique for linearizing the I(V) characteristic of the active resistor will be proposed, based on the utilization of a new linear differential amplifier, and on a current-pass circuit. The linearization of the original differential structure is achieved by compensating the quadratic characteristic of the MOS transistor operating in the saturation region by an original square-root circuit. The errors introduced by the second-order effects will be strongly reduced, while the circuit frequency response of the circuit is very good as a result of operating all MOS transistors in the saturation region. In order to design a circuit having a negative equivalent resistance, an original method specific to the proposed implementation of the active resistor circuit will be presented. The circuit is implemented in 0.35 μm CMOS technology, the SPICE simulation confirming the theoretical estimated results and showing a linearity error under a percent for an extended input range (± 500 mV) and a small value of the supply voltage (± 3 V).

A 1-V 45-GHz Balanced Amplifier With 21.5-dB Gain Using 0.18-$\mu{\hbox {m}}$ CMOS Technology

A fully integrated balanced amplifier was realized in a standard 0.18-mum CMOS technology. From the measured-parameters, a gain up to 21.5 dB was achieved at 45.4 GHz under a supply voltage of only 1 V and a total power consumption of 89 mW. An effective technique, i.e., pi-type parallel resonance, was proposed to enhance the device and circuit frequency response. In addition, the semicoaxial line structure was used to reduce the signal loss and physical size of the Lange couplers in the amplifier. To the best of the authors' knowledge, the proposed balanced amplifier demonstrated the highest operation frequency and the lowest operation voltage among the published millimeter-wave amplifiers using a similar technology.

Generalised frequency response as applied to circuits with time varying elements

The paper introduces the application of the generalised frequency response, to the determination of the frequency response of circuits with time varying elements. The approach is mainly via the analysis of illustrative cases based on active filters of increasing complexity. Where possible alternative, more conventional, analysis has also been performed to serve as a comparison. Approximations to the exact analytic results are compared with numerical solutions.

Approximate solutions to a dynamic worst-case tolerance analysis problem

A dynamic tolerance problem for linear circuits is considered. More specifically, the worst-case analysis of the scalar step response under interval variations of the circuit parameters is treated. Approximate solutions to the dynamic tolerance analysis problem considered are suggested, two of them having the property of enclosing the exact solution of the problem. A method for determining the approximate solutions introduced is proposed. It is based on the known integral relationship between the time response and the real part of the frequency response for linear circuits on one hand and certain basic ideas and techniques from interval analysis on the other. The method reduces to evaluating some interval extension or the range of certain sums or integrals of the real part of the circuit frequency response with respect to the parameter variations.

Microelectronic circuits and devices

1. Review of Linear Circuit Theory. Kirchhoff's voltage and current laws. Voltage bus notation. Definition of voltage-current characteristic. Superposition in linear circuits. Resistive circuits. Thevenin equivalent circuits. Norton equivalent circuits. Voltage and current division. Single time constant resistor-capacitor circuits. 2. Operational Amplifiers. Integrated-circuit operational amplifier. Simplified Op-amp model. Simplified Op-amp model. Ideal Op-amp approximation. Linear op-amp circuits. Nonlinear operational amplifier circuits. Nonideal properties of operational amplifiers. 3. Introduction to Nonlinear Circuit Elements. Basic properties of nonlinear elements. Graphical analysis with one nonlinear circuit element. Examples of two-terminal nonlinear devices. Graphical method with time-varying sources. Iterative mathematical solutions. Piecewise linear modeling of two-terminal nonlinear devices. 4. Signal Processing and Conditioning with Two-terminal Nonlinear Devices. The transfer characteristic. Clipping and limiting circuits. Rectifier circuits. Power supply circuits. Precision rectifier circuits. 5. Three Terminal Devices. Definition of a three terminal device. Field-effect transistors. Bipolar-junction transistor. Upward slope of transistor V-1 characteristics. Photonic devices. Temperature dependence of devices. Power limitations of device operation. 6. Basic Circuits Containing Three-Terminal Devices. Inverter configuration. Voltage-follower configuration. Current-follower configuration. Operation in the digital regime. 7. Analog Amplification. Definition of a signal. Active and passive circuits. Biasing. Small-signal modeling of analog circuits. Two-port amplifier representation. 8. Differential Amplifiers. Basic differential-amplifier topology. Differential- and common-mode signals. BJT differential amplifier. MOSFET and JFET differential amplifiers. Large-signal performance of differential amplifiers. 9. Frequency Response and Time-Dependent Circuit Behavior. Sources of capacitance and inductance in electronic circuits. Sinusoidal steady-state amplifier response. Frequency response of circuits containing capacitors. Frequency response of the differential amplifier. Time response of electronic circuits. 10. Feedback and Stability. The negative-feedback loop. General requirements of feedback circuits. Effects of feedback on amplifier performance. The four basic amplifier types. The four feedback topologies. Effect of feedback connections on amplifier port resistance. Examples of real feedback amplifiers. Feedback-loop stability. 11. Multistage and Power Amplifiers. Input and output loading. Two-port amplifier cascade. Multistage amplifier biasing. DC level shifting. Differential-amplifier cascade. Power-amplification output stages. Integrated-circuit power amplifiers. Power devices. 12. Analog Integrated Circuits. Basic operational-amplifier cascade. Case Study: The LM741 Bipolar operational amplifier. Case Study: A simple CMOS Operational Amplifier. 13. Active Filters and Oscillators. A simple first-order active filter. Ideal filter functions. Second-order filter responses. Active filter cascading. Magnitude and frequency scaling. Switched-capacitor networks and filters. Oscillators. 14. Digital Circuits. Fundamental concepts of digital circuits. CMOS logic family. NMOS logic family. TTL logic family. Emitter-coupled logic family. BiCMOS logic circuits. 15. Fundamentals of Digital Systems. Sequential logic circuits. Multivibrator circuits. Digital memory. Analog-to-digital interfacing. 16. Electronic Design. An overview of the design process. The tools of electronic design. Open-ended design problems. Analog integrated-circuit design problems. Appendix A: Physics of Semiconductor Devices. Electronic materials. Qualitative description of holes. Impurities. Carrier densities within a semiconductor. Current flow in a semiconductor. Diffusion gradient within a semiconductor. Derivation of the v-i characteristic of the PN junction diode. The bipolar junction transistor. The metal-oxide-semiconductor field-effect transistor. Appendix B: Semiconductor Device and Integrated Circuit Fabrication. An overview of the fabrication process. Epitaxial growth. Oxidation. Wafer doping. Film deposition. Wafer etching. Lithographic processing. A MOS fabrication sequence. A BJT fabrication sequence. Appendix C: Computer-Aided Circuit Design Using SPICE and PSpice. Use of SPICE. Capabilities of SPICE and PSPICE. Circuit description. Types of analyses. Generating output. References. Appendix D: Resistor Color Codes and Standard Values. Appendix E: Suggestions for Further Reading. Appendix F: Answers to Selected Problems.

Frequency response of RC-active circuits using Norton amplifiers with highly asymmetrical slew rates

A nonlinear model for the frequency-domain analysis of RC-active circuits based on amplifiers with highly asymmetrical slew rates is shown. The model uses the describing function for a sinusoidal-plus-bias signal (SBDF), with the defining integrals calculated by Steklov's approximation. Hence, explicit expressions for the circuit frequency response and for the amplifier output bias are obtained. Analytical expressions are derived for the main parameters describing the regenerative phenomena, and a necessary and sufficient condition for phenomena-free circuits is obtained.

Analysis of a simple circuit for constant temperature anemometry

Perturbation equations describing the response of hot wires and hot films operating in a simple constant temperature circuit are developed. The heat transfer model shows that at low frequencies (a( omega /Ks)12/<or=1, where omega is the perturbation frequency and a and Ks are the substrate radius and thermal diffusivity respectively) the hot film responds like a hot wire. At high frequencies (a( omega /Ks)12/>>1) the hot film rolls off at 30 dB/decade. Experimental measurements of the circuit frequency response to a voltage perturbation for both a hot film and a hot wire show good agreement with theory if the calculations use the measured probe time constants, and when thermal end losses are taken into account.

Relationship between frequency response and settling time of operational amplifiers

The effects of pole-zero pairs (doublets) on the frequency response and settling time of operational amplifiers are explored using analytical techniques and computer simulation. It is shown that doublets which produce only minor changes in circuit frequency response can produce major changes in settling time. The importance of doublet spacing and frequency are examined. It is shown that settling time always improves as doublet spacing is reduced whereas the effect of doublet frequency is different for 0.1 and 0.01 percent error bands. Finally it is shown that simple analytical formulas can be used to estimate the influence of frequency doublets on amplifier settling time.