We perfected a hand-signal system so that he could keep me informed of hazards.

我们完善了一套手语体系，以便他能告知我危险。

《柯林斯英汉双解大词典》

The device would generate a pulse that would stimulate other parts of the skin, giving the kind of signal 'my (artificial) hand is touching something', for instance.

这种设备将会发出脉冲来刺激其他部位的皮肤，发出例如‘我的手触到了一些东西’这样的信号。

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Holding the phone in a more natural way that covers the bottom half of the phone with our hand did affect the signal.

用手盖住手机底部的一半是种更自然的握资，但这确实会影响信号。

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What happened in that case is he has learned that the raising of a hand is a signal that he is about to be hit and so he responds to that signal.

在这个例子中，他知道,举起的手臂是他即将挨打的信号,因此他对这个信号作出了反应。

耶鲁公开课 - 心理学导论课程节选

After the publication of the book, a drama scholar wrote to Mr. Unsworth asking for his source on the hand-signal system.

WSJ: A Tribute to Barry Unsworth | Dear Book Lover

Long before my translator - who is switching form Greek to Arabic to French - gets it right, Mr Lamhoud's hand movements signal what happened.

BBC: Greece asylum: Journey through a broken system

Thompson turned around in time to watch it fly toward a row of defenseless photographers sitting on the baseline, and then raised his hand to signal it was his team's ball since he hadn't touched it last.

WSJ: One NBA Player's Life of Constant Rejection: Tristan Thompson