Abstract: A speed reducer includes a first transmission shaft, an eccentric wheel, a first roller assembly, a rotating wheel, a second roller assembly and a second transmission shaft. The rotating wheel includes a main body and an axle hole. The main body includes a convex structure and a concave structure. The convex structure is protruded from an outer periphery of the main body and has outer teeth. The outer teeth are contacted with the corresponding first rollers. The concave structure is concavely formed in a surface of the main body and includes inner teeth. The inner teeth are contacted with plural second rollers of the second roller assembly. The speed reducer of the present invention is an epicycloid-epicycloid speed reducer or a hypocycloid-hypocycloid speed reducer. Since the speed reducer is designed to have four operating situations, the speed reducer can have various reduction ratios.

Abstract: A speed reducer includes a first transmission shaft, an eccentric wheel, a first roller assembly, a rotating wheel, a second roller assembly and a second transmission shaft. The rotating wheel includes a main body and an axle hole. The main body includes a convex structure and a concave structure. The convex structure is protruded from an outer periphery of the main body and has outer teeth. The outer teeth are contacted with the corresponding first rollers. The concave structure is concavely formed in a surface of the main body and includes inner teeth. The inner teeth are contacted with plural second rollers of the second roller assembly. The speed reducer of the present invention is an epicycloid-epicycloid speed reducer or a hypocycloid-hypocycloid speed reducer. Since the speed reducer is designed to have four operating situations, the speed reducer can have various reduction ratios.

Abstract: The present invention applies spectral flatness characteristic values to simplify psychoacoustic analysis of a sound signal. If the sound signal comprises a plurality of frames, the present invention calculates the energy of the sound signal in a frequency domain, calculates a plurality of spectral flatness, and decides to use a short-block or a long-block Modified Discrete Cosine Transform accordingly. If the sound signal comprises left and right channel signals, the present invention performs psychoacoustic analysis on the sound signal to count energy of the left and right channel signals in a frequency domain, counts spectral flatness of the left and right channel signals, and decides to use middle/side transform or left and right channel encoding to transform the left and right channel signals accordingly.

Abstract: The present invention applies spectral flatness characteristic values to simplify psychoacoustic analysis of a sound signal. If the sound signal comprises a plurality of frames, the present invention calculates the energy of the sound signal in a frequency domain, calculates a plurality of spectral flatness, and decides to use a short-block or a long-block Modified Discrete Cosine Transform accordingly. If the sound signal comprises left and right channel signals, the present invention performs psychoacoustic analysis on the sound signal to count energy of the left and right channel signals in a frequency domain, counts spectral flatness of the left and right channel signals, and decides to use middle/side transform or left and right channel encoding to transform the left and right channel signals accordingly.

Abstract: A liquid crystal display (LCD) device includes an LCD panel for displaying images, a panel bezel, and a rear housing. The panel bezel contains a side plate formed on a perimeter of the panel bezel for enclosing a perimeter of the LCD panel, and a front plate monolithically formed with the side plate for enclosing a front surface of the LCD panel and acting as a front housing of the LCD device. The front plate has a viewing hole for allowing the LCD panel to be viewed through the front plate, and a plurality of holes for receiving input keys. The LCD device also contains a plurality of input keys disposed in the corresponding holes of the front plate for receiving input commands of the LCD device. The rear housing is attached to the panel bezel for enclosing the LCD panel between the panel bezel and the rear housing.