用echo signals造句子，“echo signals”造句

A Kind of Zero-crossing method for detecting Underwater small sine echo signals

Feature extraction of ultrasonic echo signals(RF);

The characteristics of the test signals were analyzed and weak defect echo signals were successfully extracted by cut-off frequency technique.

It is often misjudged the flaw echo in ultrasonic examination that the echo signals produced by sound field property and geometrical shape of the component examined according to sound field theory.