The paper introduces the principle of frequency measure based on double-counter and multi-periods pulse synchronization method, and the designing with microprocessor is offered.

介绍了双计数器多周期同步法频率测量原理，给出了用单片机实现的具体实现方案。

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As United held firm, with an ever-present menace on the counter-attack, Ancelotti made a double change with 20 minutes left, replacing Yuri Zhirkov and Drogba with Florent Malouda and Nicolas Anelka.

BBC: Chelsea 0-1 Man Utd

My own estimate is that there are about 10, 000 white hat security researchers working full time to counter malware (100 vendors X 50 average and double that for independents.) I am still working on an estimate of the number arrayed on the other side of this battle ground.

FORBES: Battleground Cyberspace: Hackers vs. White Hats

Although the housing market has stabilized over the last half a year, the chorus calling for a double dip in housing is growing louder as data such as this runs counter to a sustainable recovery thesis.

FORBES: Housing Starts Stumble After Stimulus