此题为判断题(对,错)。
B.in_1
C.in_2
D.in_3
An analog signal is sampled, quantized and encoded into a binary PCM wave. The number of representation levels used is L=32768. A synchronizing bit is added at the end of each codeword representing a sample of the analog signal. The resulting PCM wave is transmitted over a channel of bandwidth BT=28 (kHz), using a binary PAM system with raised-cosine spectrum, where the roll-off factor is a=0.75. Then, the information is transmitted at the rate Rb=____ (bps) through the channel. The analog signal is sampled at the rate fs= (Hz). The maximum possible value for the highest frequency component of the analog signal is fH= (Hz).
A、Rb=32k, fs=2k, fH=1k
B、Rb=32k, fs=4k, fH=2k
C、Rb=48k, fs=2k, fH=1k
D、Rb=48k, fs=4k, fH=2k
Translate into Chinese. 1.Each cell phone, when it makes a call, is connected (via its antenna and electromagnetic radiation to the base station with the best apparent communication path. The base stations in a given area are connected to a mobile telephone switching office (MTSO) by high speed wire, fiber, or microwave connections. 2.All of the newer cellular systems are digital (I.e., use a binary interface), and thus, in principle, can be used for voice or data. Since these cellular systems, and their standards, originally focused on telephony, the current data rates and delays in cellular systems are essentially determined by voice requirements. 3.One approach to channel measurement is to allocate a certain portion of each transmitted packet for that purpose. During this period, a known probing sequence is transmitted and the receiver uses this known sequence either to estimate the current values for the taps in the discrete-time baseband model of the channel or to measure the actual paths in a continuous-time baseband model. 4.It appears that many wireless situations, particularly those in cellular and local area networks contain a relatively small number of significant coherent paths, and if the bandwidth is large enough to resolve these paths, then the gain is far greater than that indicated in the example above. 5.The resulting binary stream, after adding the long PN sequence, is at a rate of 1.2288 Mbps. This stream is duplicated into two streams prior to being quadrature modulated onto a cosine and sine carrier.
【填空题】再听录音或仔细阅读文本,并完成测验。 Programming Languages Student: Professor Martin, I just finished my Java assignment, but I still have some questions. Instructor: Sure, Andrew. Student: I’m having a hard time keeping all the languages straight. There are so many. Instructor: There are quite a few. Which ones are you having trouble with? Student: All of them. I think it’s confusing to have all these (1). Instructor: I see where you’re coming from. It’s a lot to learn. Student: But why are there so many different languages? Instructor: The first reason is that it makes developing (2) easier. Student: How is that? Instructor: The computer only understands commands in (3) language, or (4) digits. It would take programmers a long time to write programs in binary format. Student: I see. Instructor: Instead, programmers use human readable (5) languages, like Java. That allows us to write programs faster than ever before. Student: I understand that. But why are there so many human-readable programming languages? Instructor: Some human-readable programming languages are more appropriate for certain kinds of software. Does that answer your question? Student: Yes. I guess that makes sense. Thanks.
1.Here is a binary tree。a. write the order of the nodes visited in : 1. An inorder traversal 2. A preorder traversal 3. A post order traversal b. Is this a binary search tree? Why?
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