This notion of inter-domain transformation is useful in many fields of study-for example, moving from the time domain into the frequency domain in the field of signal processing.
这种域间转换的概念在很多领域的学习中都很有用—例如，信号处理领域中从时间域移入频率域。
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The theoretical analysis and the results of computer simulation showed that it is possible to build a cancelling signal by means of code transformation.
Multiplier is the circuit which is conformed of nonlinear elements and can make two signal multiplied so that it can implement frequency transformation.