Influence of electrical filter bandwidth on the performance of frequency-scanning BOTDR

2019 ◽  
Author(s):  
Qinglin Wang ◽  
Qing Bai ◽  
Hang Gu ◽  
Wei Yan ◽  
Changshuo Liang ◽  
...  
Keyword(s):  
Filter Bandwidth ◽  
Electrical Filter ◽  
Frequency Scanning

Acoustic microscopy techniques for the inspection of integrated circuit devices and packages

1992 ◽  
Vol 50 (2) ◽  
pp. 966-967
Author(s):  
Thomas M. Moore
Keyword(s):  
Integrated Circuit ◽  
Acoustic Microscopy ◽  
Hybrid Technique ◽  
Frequency Scanning ◽  
Ic Packaging ◽  
Ic Package ◽  
Microscopy Techniques ◽  
Ic Package Inspection ◽  
Pulse Echo ◽  
Scanning Acoustic Microscope

In the last decade, a variety of characterization techniques based on acoustic phenomena have come into widespread use. Characteristics of matter waves such as their ability to penetrate optically opaque solids and produce image contrast based on acoustic impedance differences have made these techniques attractive to semiconductor and integrated circuit (IC) packaging researchers.These techniques can be divided into two groups. The first group includes techniques primarily applied to IC package inspection which take advantage of the ability of ultrasound to penetrate deeply and nondestructively through optically opaque solids. C-mode Acoustic Microscopy (C-AM) is a recently developed hybrid technique which combines the narrow-band pulse-echo piezotransducers of conventional C-scan recording with the precision scanning and sophisticated signal analysis capabilities normally associated with the high frequency Scanning Acoustic Microscope (SAM). A single piezotransducer is scanned over the sample and both transmits acoustic pulses into the sample and receives acoustic echo signals from the sample.

Children's Performance on a Binaural Fusion Task

1981 ◽  
Vol 24 (4) ◽  
pp. 520-525 ◽  
Author(s):  
Bruce L. Plakke ◽  
Daniel J. Orchik ◽  
Daniel S. Beasley
Keyword(s):  
Enhancement Effect ◽  
Sensation Level ◽  
Large Measure ◽  
Filter Bandwidth ◽  
Research Results ◽  
Presentation Modes ◽  
Monosyllabic Words ◽  
Better Than

Binaural auditory fusion of 108 children (4, 6, and 8 years old) was studied using three lists of monosyllabic words (WIPI) presented at two sensation levels (30 and 40 dB). The words were processed to produce three bandwidth conditions (100, 300, 600 Hz) and were administered via three presentation modes (binaural fusion 1, diotic, binaural fusion 2). Results showed improved discrimination scores with increasing age, sensation level, and filter bandwidth. Diotic scores were better than binaural fusion scores for the narrower bandwidth conditions, but the diotic enhancement effect was seriously compromised in the widest bandwidth (600 Hz) condition. The results confirmed the contention that prior research results were equivocal due, in large measure, to procedural variability. Methods for reducing such variability and enhancing the clinical viability of binaural fusion tasks are suggested.

Envelope Analysis Based on the Combination of Morlet Wavelet and Kurtogram

2012 ◽  
Vol 490-495 ◽  
pp. 305-308
Author(s):  
Yu Liang ◽  
Yu Guo ◽  
Chuan Hui Wu ◽  
Yan Gao
Keyword(s):  
Frequency Band ◽  
Filter Banks ◽  
Morlet Wavelet ◽  
Center Frequency ◽  
Band Pass Filter ◽  
Pass Filter ◽  
Filter Bandwidth ◽  
Envelope Analysis ◽  
Band Pass ◽  
Complex Morlet Wavelet

Envelope analysis based on the combination of complex Morlet wavelet and Kurtogram have advantages of automatic calculation of the center frequency and bandwidth of required band-pass filter. However, there are some drawbacks in the traditional algorithm, which include that the filter bandwidth is not -3dB bandwidth and the analysis frequency band covered by the filter-banks are inconsistent at different levels. A new algorithm is introduced in this paper. Through it, both optimal center frequency and bandwidth of band-pass filter in the envelop analysis can be obtained adaptively. Meanwhile, it ensures that the filters in the filter-banks are overlapped at the point of -3dB bandwidth and the consistency of frequency band that the filter-banks covered.

Precision Motion of Iterative Learning Controller Using Adaptive Filter Bandwidth Tuning by Improved Particle Swarm Optimization Technique

2013 ◽  
Vol 376 ◽  
pp. 349-353
Author(s):  
Yi Cheng Huang ◽  
Shu Ting Li ◽  
Kuan Heng Peng
Keyword(s):  
Particle Swarm Optimization ◽  
Pid Controller ◽  
Iterative Learning ◽  
Swarm Optimization ◽  
Filter Bandwidth ◽  
Improved Particle Swarm Optimization ◽  
Simulation Results ◽  
Adaptive Bandwidth ◽  
Precision Motion ◽  
Zero Phase

This paper utilized the Improved Particle Swarm Optimization (IPSO) technique for adjusting the gains of PID and the bandwidth of zero-phase Butterworth Filter of an Iterative Learning Controller (ILC) for precision motion. Simulation results show that IPSO-ILC-PID controller without adaptive bandwidth filter tuning have the chance of producing high frequencies in the error signals when the filter bandwidth is fixed for every repetition. However the learnable and unlearnable error signals should be separated for bettering control process. Thus the adaptive bandwidth of a zero phase filter in ILC-PID controller with IPSO tuning is applied to one single motion axis of a CNC table machine. Simulation results show that the developed controller can cancel the errors efficiently as repetition goes. The frequency response of the error signals is analyzed by the empirical mode decomposition (EMD) and the Hilbert-Huang Transform (HHT) method. Errors are reduced and validated by ILC with adaptive bandwidth filtering design.

Filter bandwidth and subcarrier spacing tolerance of single-carrier 32 Gbaud PDM-QPSK

2011 ◽  
Author(s):  
Andrew Stark ◽  
Yu-Ting Hsueh ◽  
Thomas Detwiler ◽  
Mark Filer ◽  
Sorin Tibuleac ◽  
...  
Keyword(s):  
Filter Bandwidth ◽  
Single Carrier

Carbon-nanotube field-emitter driven compact, frequency-scanning THz source

2007 ◽  
Author(s):  
S. J. Papadakis ◽  
A. H. Monica ◽  
J. Yu ◽  
J. A. Miragliotta ◽  
R. Osiander ◽  
...  
Keyword(s):  
Carbon Nanotube ◽  
Field Emitter ◽  
Frequency Scanning
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