A means of error control whose purpose is to ensure that the information received by an acceptor is as intended by the source. There must be some means for the acceptor to deduce when received information contains errors, and a mechanism for removing them.; 一种控制错误的手段,其目的是为了保证被接收器收到的信息是信号源发送的信息。 因此,当接收到的信息中含有错误时,接收器必须有推断的手段和消除错误的机制。