An Efficient VLSI Architecture of Frequency Domain Kurtosis for Non-Stationary Acoustic Noise Measurements

2006 ◽  
Author(s):  
Sheau-fang Lei ◽  
Lih-yih Chiou ◽  
Hsieh-wei Lee ◽  
Bin-da Liu
Keyword(s):  
Frequency Domain ◽  
Acoustic Noise ◽  
Vlsi Architecture ◽  
Noise Measurements

A Computationally Efficient Multichannel Active Road Noise Control System

2014 ◽  
Vol 137 (1) ◽  
Author(s):  
Jie Duan ◽  
Mingfeng Li ◽  
Teik C. Lim ◽  
Ming-Ran Lee ◽  
Ming-Te Cheng ◽  
...  
Keyword(s):  
Frequency Domain ◽  
Time Domain ◽  
Noise Control ◽  
Acoustic Noise ◽  
Reference Signal ◽  
Active Noise Control ◽  
Computational Cost ◽  
Road Noise ◽  
Time Frequency ◽  
Fxlms Algorithm

A multichannel active noise control (ANC) system has been developed for a vehicle application, which employs loudspeakers to reduce the low-frequency road noise. Six accelerometers were attached to the vehicle structure to provide the reference signal for the feedforward control strategy, and two loudspeakers and two microphones were applied to attenuate acoustic noise near the headrest of the driver's seat. To avoid large computational burden caused by the conventional time-domain filtered-x least mean square (FXLMS) algorithm, a time-frequency domain FXLMS (TF-FXLMS) algorithm is proposed. The proposed algorithm calculates the gradient estimate and filtered reference signal in the frequency domain to reduce the computational requirement, while also updates the control signals in the time domain to avoid delay. A comprehensive computational complexity analysis is conducted to demonstrate that the proposed algorithm requires significantly lower computational cost as compared to the conventional FXLMS algorithm.

Background Noise Definition for Acoustic Emission Leak Monitoring System at GTP Molve

2002 ◽  
Author(s):  
Goran Hudec ◽  
Boris Muvrin
Keyword(s):  
Acoustic Emission ◽  
Natural Gas ◽  
Monitoring System ◽  
Background Noise ◽  
Acoustic Noise ◽  
Treatment Plant ◽  
Environment Impact ◽  
Gas Treatment ◽  
Noise Measurements ◽  
The Impact

In Croatian Podravina relatively large quantities of natural gas was discovered. From various fields (Molve, Kalinovec, Stari Gradec) natural gas is pipelined to Gas Treatment Plant (GTP) Molve. Here, at GTP Molve III, technological procedures for purification of natural gas and its distribution are performed. With yearly natural gas production of 3,5 109 m3 GTP Molve III is major Croatian energy resource. Its safety and environment impact is matter of concern. Continuous acoustic emission leak monitoring system for Gas Treatment Plant (GTP) Molve as an improvement in technological and environment safety is considered. Application of a leak monitoring system under industrial conditions is a problem setting specific demands. In the paper attention is paid to some aspects of acoustic emission system implementation and the acoustic background noise definition problem. Acoustic noise measurements at a GTP Molve III were performed and some results considering background noise are presented. In the paper acoustic noise measurements performed at a GTP Molve III were presented. Across the GTP Molve III acoustical background have different spectral and amplitude characteristic. In the input area, measurements presented at a first group of measuring points included the impact of sand moved by gas fluid. Sand hits should be distinguished from acoustic emission caused by growing cracks. Motors noise and turbulence around valves are probably the main source of background noise on second group of measuring points. The conclusion is that background noise across the plant is highly different. Patterns found in one part of plant could not be applied on others measuring points. Background noise and its characterization are one of main problems solved before reliable operation of acoustic monitoring system could be applied. It is found that at GTP Molve III acoustic background is complicated, consisting of different sources at different part of a plant.

Phase Noise Measurements in the Frequency Domain

2005 ◽  
Author(s):  
A.L. Lance ◽  
W.D. Seal ◽  
F.G. Mendoza ◽  
N. Hudson
Keyword(s):  
Phase Noise ◽  
Frequency Domain ◽  
Noise Measurements

A VLSI Implementation of Filterbank for MPEG2/4 AAC Encoder

2011 ◽  
Vol 378-379 ◽  
pp. 569-572
Author(s):  
Tsung Han Tsai ◽  
Yu Jie Sha
Keyword(s):  
Frequency Domain ◽  
Discrete Cosine Transform ◽  
Time Domain ◽  
Vlsi Architecture ◽  
Low Complexity ◽  
Hardware Cost ◽  
Audio Quality ◽  
Input Signals ◽  
Audio Files ◽  
The Time Domain

In this paper, we proposed a VLSI architecture of the modified discrete cosine transform (MDCT) for MPEG 2/4 AAC encoders. The MDCT transforms the time domain input signals to the frequency domain spectrums. It is considered one of the most computational intensive part in implementing the AAC encoder. The AAC encoder allows four types of audio blocks while encoding the audio files. With our algorithm, the proposed design can share the coefficients needed in the MDCT. Moreover, we used a 2-dimensional folding technique to reduce the hardware cost while maintaining the audio quality. The proposed design is realized in TSMC 0.18-um 1P6M technology and is operated at 50 MHz. With these techniques on special hardware design, the result shows some advantages on low complexity.

Sign in / Sign up

Export Citation Format

Share Document