Industrial machines like punching machines and presses can generate structure-borne impact noise, with noise levels exceeding the tresholds, imposed by legal regulations on noise emission. This paper presents an approach of non-collocated active structural acoustic control of transient noise, produced by a repetitive impact excitation. Although there is a significant difference in nature betwee...

The scattering of a fluid-structure coupled wave at a flanged junction between two flexible waveguides is investigated. The flange is assumed to be rigid on one side and soft on the other; this enables a solution to be formulated using mode-matching. It is shown that both the choice of the edge conditions imposed on the plates at the junction and the choice of incident forcing significantly aff...

a novel low noise trans-impedance amplifier is proposed using low cost 0.18 µm cmos technology. a resistive-capacitive feedback is used to extend the bandwidth of the amplifier. as the structure is inductor less, it is suitable for low cost integrated optical interconnects. in this paper improved particle swarm optimization have applied to determine optimal trans-resistance and noise of propose...

The noise generated by a quadrotor biplane unmanned aerial system (UAS) is studied computationally for various conditions in terms of the UAS pitch angle, propellers rotating velocity (RPM), and speed to understand physics involved its aeroacoustics structure-borne noise. k-ω SST turbulence model Ffowcs Williams-Hawkings equations are used solve flow acoustics fields, respectively. sound pressu...

In this paper, an intuitive analysis of a phase noise reduction technique is done, and then a modified structure is proposed to achieve higher phase noise reduction than the original one. This method reduces the impact of noise sources on the phase noise by decreasing closed-loop gain in zero-crossings points and moving this high closed-loop gain to the non-zero-crossings points. This reduction...