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Resistors
Published in Kevin Robinson, Practical Audio Electronics, 2020
The frequency response of a device or system represents how that system behaves when presented with signals of different frequencies. It can be thought of as a particular kind of transfer function where the question is how the level of the output changes as the frequency of the input signal is changed. As can be seen from the graph, the answer in this instance is that the output level remains constant regardless of the frequency of the input. This is in contrast to the behaviour of the next two components which are examined: capacitors and inductors. In that case very clear and predictable variations are observed, which lead to the conclusion that capacitors and inductors are ideal components for building filters – circuits which modify the frequency balance of a signal.
Filters
Published in Afshin Samani, An Introduction to Signal Processing for Non-Engineers, 2019
What in practice one can achieve with frequency-based filters does not have a sharp and clear-cut frequency response as shown in Figure 8.1. There will always be a transition phase around the cut-off frequency. The cut-off frequency is often defined as a threshold where the power of the output signal drops to half of the power of components with no attenuation (Widmann, Schröger, and Maess, 2015) (often where the magnitude of the frequency response is 1, the filter does not attenuate the frequency components in that range). I already stated that the power spectrum of the output is proportional to the square of the magnitude of the system frequency response, and therefore, the cut-off frequency is the frequency limit where the magnitude of the frequency response drops to 12 of its magnitude when no attenuation is applied (often where the magnitude is 1).
Machining Dynamics
Published in David A. Stephenson, John S. Agapiou, Metal Cutting Theory and Practice, 2018
David A. Stephenson, John S. Agapiou
The frequency response of a system is defined as the steady-state response of the system to a sinusoidal input signal. The output of a linear system to such an input is also sinusoidal with the same frequency in the steady state; it differs from the input wave form only in the amplitude and phase angle. This method is easily applied to experimentally determine the frequency response and the TF of a system. The TF in the frequency response method can be also obtained from the TF in the s-plane by replacing s with j, where j √-1 The disadvantage of the frequency response method for analysis and design is the indirect link between the frequency domain and the time domain. The frequency domain approach is also limited in applicability to linear time-invariant systems; it is particularly limited when considering multivariable control systems due to the emphasis on the input—output relationship of TFs. The frequency response method analyzes a system based on the amplitude and phase relationships between sinusoidal curves, which is a natural approach since many machining vibrations result from rotating forces or imbalance.
Optimum Parameters for Large Mass Ratio TMDs Using Frequency Response Function
Published in Journal of Earthquake Engineering, 2021
Mahmood Yahyai, Leila Zebarjad, Monique Head, Mehdi Shokouhian
The design parameters of TMD including the frequency ratio, i.e., f= ω2/ω1, where ω12 = k1/m1 and ω22 = k2/m2, and damping ratio are determined through an optimization process such that the displacement response of the structure and the acceleration response of the TMD are minimized. For this purpose, the frequency response function (FRF) of the primary structure displacement and acceleration of TMD are selected as parameters to be monitored in the optimization process. The frequency response of a system is a frequency-dependent function which expresses how a sinusoidal signal of a given frequency on the system input is transferred through the system. Each frequency component is a sinusoidal signal with a certain amplitude and a certain frequency. Some components may be amplified, others may be attenuated, and there will be some phase lag through the system. The frequency response is an important tool for analysis and design of control systems. The optimization objectives in this study are described in the following: The difference between damping ratios of first mode and second mode of the combined system (2DOF).The maximum amplitudes of FRF curves for displacement response of the structure and acceleration of TMD.
Basic properties mapping of anodic oxides in the hafnium–niobium–tantalum ternary system
Published in Science and Technology of Advanced Materials, 2018
Andrei Ionut Mardare, Cezarina Cela Mardare, Jan Philipp Kollender, Silvia Huber, Achim Walter Hassel
Localised anodic oxides were grown potentiodynamically by SDCM along the Hf–Nb–Ta thin film combinatorial library with a potential increase rate of 100 mV s−1 using a CompactStat Potentiostat (Ivium Technologies, Eindhoven, The Netherlands). The thickness of the anodic oxides was gradually increased from 0 to 10 V (SHE) in 1 V steps, which enabled thickness (and composition) dependent oxide impedance measurements. The integrated frequency response analyser was used for this purpose in a frequency range of 106 to10−1 Hz. The impedance data was fitted in batch mode using the ZView software from Scribner Associates Inc. (Southern Pines, NC, USA). For assessing the semiconducting properties of the mixed Hf–Nb–Ta anodic oxides, Mott–Schottky analysis was performed on oxide spots previously anodised at 3 V (SHE) by varying the applied DC bias between −1 and 3 V (SHE). For all electrochemical measurements, analytical grade acetate buffer solution (CH3COOH/CH3COONa) with a fixed pH value of 6.0 was used as electrolyte.
Application of multi-scale noise tuning parameter-induced stochastic resonance for planetary gearbox diagnosis
Published in Australian Journal of Mechanical Engineering, 2022
Kuo Chi, Jianshe Kang, Xinghui Zhang, Zhao Fei
Frequency response is the response of a system with fixed parameters to different frequencies. Optimal frequency response is the optimal response of the system with optimal parameters to different frequencies. The difference between them is whether the system achieves the best parameters. Because parameter adjustment is necessary for MNTPSR-1/f β and PSR, only the optimal frequency response is analysed. Let frequency sample fs = 104Hz, sample time t= 0.5 s, sine amplitude A= 1 and GWN intensity D= 10. Driving frequency fd increase from 20 Hz to 120 Hz with step-size 4Hz. SNRs of all raw signals are about −16.021 dB. All the raw signals are proposed, respectively, by PSR and MNTPSR-1/f β with different scale parameters (J= 3, 4 and 5). Parameters (H, K) of PSR and parameters (H, K, α, β) of MNTPSR-1/f β are tuned until the SNRs of their outputs reach the max. The output SNRs versus the frequencies are shown in Figure 9. The SR output SNR decreases with the increase of driving frequency fd. It means that PSR and MNTPST are more effective for the detection of low-frequency signal than high-frequency signal. It is noteworthy that the output SNR of MNTPSR-1/f β with J= 5 is much higher than other method’s when the driving signal frequency fd is high as marked by the dotted circle in Figure 9. It means that larger scale parameter J is beneficial for MNTPSR-1/f β to detect high-frequency signals. However, the max scale parameter J should satisfy Equation .