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Ubi Sound Co., Ltd.

Yong Hun Cho

Sang Jin Park

Hiun Won

Do Sig Choi

Wan Pyo Park

Yun Do Kim

There is provided a method and apparatus for output pulse width modulation in a digital amplifier including: a determining step of adding or subtracting a value corresponding to a predetermined offset to or from an input audio signal alternately according to a period of the input audio signal, thereby determining a sign of a resulting value of adding or subtracting; a switching step of outputting the input audio signal to a first port based on the determined sign, or outputting the input audio signal to a second port after inverting the input audio signal into a positive number; an adjusting step of adding a value of a predetermined switching time to the audio signals output from the first port and the second port, and outputting a resulting value of adding; and a modulating step of performing pulse width modulation on the audio signals output from the adjusting step and outputting a first modulation signal and a second modulation signal.

Method and apparatus for pulse width modulation in a switching amplifier

A scroll-type compressor has a scroll plate with at least first and second pressure equalizing passages formed in its end plate such that the first and second pressure equalizing passages will be in the same crescent shaped pocket during at least a portion of a crescent shaped pocket's radially inward movement. The minimum pressure in a back pressure pocket will be adequate to maintain a good seal, any pressure increases will increase in accordance with the increased pressure in the crescent shaped pockets. At no point are both of the pressure equalizing passages blocked and, therefore, the pressure in the interior space does not overwhelm the effective functioning of the back pressure pocket.

Scroll-type compressor having improved pressure equalizing passage

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Kyunggi-do, South Korea

Yong Hun Cho