User:Qhzhang

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A simple life.

The research fields of Qhzhang are video processing and asynchronous circuit.

The previous video standards are MPEG4 and H.264, and the new generation video codec standard is HEVC or H.265, which has a half code rate of its former. Or we can say that HEVC has double data compression ratio compared to H.264/MPEG-4 at the same level of video quality. It can alternatively be used to provide substantially improved video quality at the same bit rate. It can support 8K UHD and resolutions up to 8192x4320.

Asynchronous circuits use internal and external events to observe system states and clockless handshake signals are used as the communication mechanism. Sometimes they are also called self-timed circuits because of their elaborate timing assumptions. Asynchronous circuits have several advantages over their synchronous counterparts, including lower power consumption, higher average-case performance, elimination of clock distribution and clock skew problems, adaptivity to process and environmental variations, less emission of electro-magnetic noise, better composability and modularity and so on. On the other hand there are also some drawbacks, in which lack of EDA tools, assurance of timing convergence and increase of area overhead are three main problems.