输出继电器（OR）通过一对（）触点将PLC的控制信号传递给负载。

试述正弦波信号、正弦波加随机噪声信号、窄带随机噪声信号和宽带随机噪声信号自相关函数的特点。

求正弦函数x（t）=x 0sin（ωt+φ）的自相关函数，并简述自相关函数特性。

Every deliberate act of wrongdoing by the master or any of the crew against the ship or cargo，without the authorization or privity of the Shipowner or his agent，is（）.

（）, or drum is used for hauling in or letting out the wires or ropes which will fasten the ship to the shore.

A salvor may be（）the whole or part of the payment due under Salvage Convention to the extent that the salvage operations have become necessary or more difficult because of fault or neglect on his part or if the salvor has been guilty of fraud or other dishonest conduct.

The （） is used for hauling in or letting out the wires or ropes.

Vessels must be（）valid certificate of nationality or certificated of registry or license.

逻辑运算符（AND、NOT、OR）的运算顺序是AND→OR→NOT。

两个不同频的正弦信号的互相关函数为余弦函数。

知信号的自相关函数为3 cos ωτ，则该信号的均方根值为（）。

逻辑运算符（AND、NOT、OR）的运算顺序是AND→OR→NOT。