● Although a given waveform. may contain frequencies over a very broad range, as

● Although a given waveform. may contain frequencies over a very broad range, as a practical matter any transmission system will be able to accommodate only a limited band of （71） . This, in turn, limits the data rate that can be carried on the transmission （72） . Asquare wave has an infinite number of frequency components and hence an infinite （73） . However, the peak amplitude of the kth frequency component, kf, is only 1/k, so most of the （74） in this waveform. is in the first few frequency components. In general, any digital waveform. will have （75） bandwidth. If we attempt to transmit this waveform. as a signal over any medium, the transmission system will limit the bandwidth that can be transmitted.

（71）A. frequencies B. connections C. diagrams D. resources

（72）A. procedure B. function C. route D. medium

（73）A. source B. bandwidth C. energy D. cost

（74）A. frequency B. energy C. amplitude D. phase

（75）A. small B. limited C. infinite D. finite

（71）

A. frequencies

B. connections

C. diagrams

D. resources

（72）

A. procedure

B. function

C. route

D. medium

（73）

A. source

B. bandwidth

C. energy

D. cost

（74）

A. frequency

B. energy

C. amplitude

D. phase

（75）

A. small

B. limited

C. infinite

D. finite

正确答案：

A,D,B,B,C