Miartech, Inc.

Chaosheng Song

Xiaoyan Chen

Gang Gou

The present invention relates to a method and an apparatus for spread spectrum modulation and demodulation using a special spread spectrum sequence, characterized in that Golay complementary codes are modulated onto orthogonal channels such that a corresponding complex complementary code is obtained. The signal spread by such complex complementary code has a low peak-to-average power ratio, a sound self-correlation property and cross-correlation property, which can well solve the problem of multi-access interference such that the communication performance of the entire system is improved.

Methods and apparatus for spread spectrum modulation and demodulation

The present invention relates to an apparatus for accurately detecting a mains phase. The apparatus is constructed with a zero-crossing detector, a digital phase detector, a digital loop filter, and a digital controlled oscillator (DCO) of a direct digital synthesized (DDS) manner. The present apparatus employs an all-digital loop architecture and a high sampling clock to recover a signal with a phase orthogonal with the mains signal and a frequency the same as the mains signal. And jitters in the recovered signal are less than 10 us. The present apparatus is capable of implementing signal tracking of a zero frequency error and a zero phase in a wide range, and can provide a detection result of excellent performance for the power line carrier communication, mains frequency detection, etc.

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Shanghai, China

Chaosheng Song