1) Read about Pulse Code Modulation on Wikipedia or another source. Briefly desc
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Question
1) Read about Pulse Code Modulation on Wikipedia or another source. Briefly describe at least two real-world uses of PCM, including sampling rate and the number of bits used to represent each sample. Explain why the two uses benefit from the differences in sampling rate and bit size.
2) Some transmission media, such as optical fiber, can propagate only analog signals.
a) true b) false
3) More efficient use of bandwidth can be achieved if each signaling element represents more than one bit.
a) true b) false
4) It is possible with current technology to create a transmission system which has zero transmission errors.
a) true b) false
5) The simplest error detecting scheme is to append a parity bit to the end of a block of data.
a) true b) false
6) The biphase codes are known as self-clocking codes. The Manchester codes are examples of biphase codes.
a) true b) false
7) Cyclic Redundancy Check (CRC) is a form of error correction.
a) true b) false
8) Which of the following is an error correction technique? (Check all that apply)
a) Parity, b) Forward Error Correction c) Internet checksum d) cylic redundancy check
9) It is often desirable to have a separate communication path for control information.
a) true b) false
10) Sliding window flow control allows only one frame to be "in the pipe" at a time.
a) true b) false
11) Sliding-window flow control makes better use of the network capacity than stop-and-wait flow control.
a) true b) false
12) The type of error control most often used with sliding-window flow control:
a) selective-reject ARQ b) stop and wait ARQ c) high level data link control d) go back N ARQ
13) Forward error correction is often used in ___ transmission, because the error rates are higher and retransmission more costly.
a) optical fiber b) wireless c) twisted pair
14) The process of converting analog input into digital data is called
a) flow control b) FEC c) digitization d) modulation
15) Cyclic Redundancy Check (CRC) appends a frame check sequence (FCS) to the end of a frame of data.
a) true b) false
Explanation / Answer
Applications of PCM:
1) PCM is used with T-1 and T-3 carrier systems. These carrier systems support digitized voice transmission and are majorly used by ISP's. T-1 provides a transmission rate of 1.544 Mbps. T3 carrier system provides 44.736 Mbps of transmission speed. These carrier systems combine the PCM signals from many lines and transmit them over a single cable or other medium.
2) Another use of PCM is for music audio playback of music CDs.
Q.2) True. Some media such as optical fiber and satellite only propagate analog signals.
Q.3) True
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