English to Chinese Tech/Engineering Automotive / Cars & Trucks 电子信号

To representing and communicate a magnitude of this kind in theory, it is sufficient to assign a number to each of these levels that need not necessarily be progressive and may therefore be made up of few digits.

a magnitude of this kind 是指数字信号。这里的 that need not necessarily be progressive and may therefore be made up of few digits是指levels还是指前面的number，意思如何理解？