Browsing by Author "Hsu, HW"

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High frequency reconstruction for band-limited audio signals
(2003)
Liu, CM
;
Lee, WC
;
Hsu, HW
;
資訊工程學系
;
Department of Computer Science
Current existing digital audio signals are always restricted by sampling rates and bandwidth fit for the various storages and communication bandwidth. Take for example the widely spread mp3 tracks encoded by the standard MPEG1 layer 3. The audio bandwidth in MP3 is restricted to 16 kHz due to the protocols constraints defined. This paper presents the method to reconstruct the lost high frequency components from the band-limited signals. Both the subjective and objective measures have been conducted and shown the better quality. Especially, the important objective measurement by the perceptual evaluation of audio quality system, which is the recommendation system by ITU-R Task Group 10/4 has proven a significant quality improvement.
The effects of post excimer laser annealing on (Ba,Sr)TiO3 thin films at low substrate temperatures
(2003-04-01)
Shye, DC
;
Chiou, BS
;
Hwang, CC
;
Jaing, CC
;
Hsu, HW
The amorphous (Ba,Sr)TiO3 (alpha-BST) films sputtered onto the Pt/TiN/Ti/Si substrates are greatly improved using the excimer laser annealing (ELA) technique of wavelength 248 nm at low substrate temperature 300degreesC. The dielectric constant of the alpha-BST film is remarkably enhanced from 80 to over 250 after ELA treatment. The heat conduction analysis indicates that a very shallow light absorption depth of the wavelength 248 nm for the BST film behaves an excellent thermal property, which doesn't,damage the underlayer films during ELA treatment. Besides, the leakage current of ELA-BST films is strongly influenced by the laser energy fluence (LEF). The detailed mechanisms of the crystallinity and the electric properties am systematically studied in this report.