A digital signal processing way is established to obtain ultrasonic signal frequency shift in the test of high sand content fluid flow.

笔者采用数字手段去测取超声波信号的频差，通过频差法可得出流体的平均速度，进而获得高含沙量流体的流量。

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"It will signal a dramatic shift to a cleaner, more sustainable method of providing frequency regulation on the grid," Beacon CEO Bill Capp told the GridWeek conference in Washington last week.

“这是一个巨大的改变，我们可以用更环保、更持续的方法来让电网实现频率的调整。” 灯塔公司首席执行官比尔·凯普上周在华盛顿出席电网周（GridWeek）大会时说道。

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It is an important technology to shift the frequency in digital vocal (musical) signal processing.

频移处理是数字语音(音乐)信号处理中一项十分重要的技术。

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And since a moving object causes a tiny change (known as a Doppler shift) in the frequency of the reflected signal, Silent Sentry can also calculate how fast it is moving.

ECONOMIST: Remote sensing