# 5 Draw the graph of the NRZ-L scheme using each of the following data streams,assuming that the last signa11evel has been positive.

5 Draw the graph of the NRZ-L scheme using each of the following data streams,assuming that the last signa11evel has been positive. From the graphs, guess thebandwidth for this scheme using the average number of changes in the signal level.Compare your guess with the corresp.onding entry in Table 4.1.a. 00000000b. 11111111c. 01010101d. 00110011138 CHAPTER 4 DIGITAL TRANSMISSION16. Repeat Exercise 15 for the NRZ-I scheme.

To draw the graph of the NRZ-L (Non-Return to Zero Level) scheme, we will represent the signal levels as either high or low, depending on the input data stream. In NRZ-L, a high signal level is represented by a positive voltage, and a low signal level is represented by zero voltage. We assume that the last signal level is positive.

a. 00000000:
In NRZ-L, the signal level remains at low (zero voltage) for consecutive 0s. Therefore, the graph for this data stream would be a flat line at low signal level (zero voltage).

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b. 11111111:
In NRZ-L, the signal level remains at high (positive voltage) for consecutive 1s. Therefore, the graph for this data stream would be a flat line at high signal level (positive voltage).

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c. 01010101:
In NRZ-L, the signal level alternates between high and low for consecutive 0s and 1s, respectively. Therefore, the graph for this data stream would alternate between high and low signal levels.

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d. 00110011138:
In NRZ-L, the signal level remains the same for consecutive 0s and changes for consecutive 1s. Therefore, the graph for this data stream would have transitions at the changes from 0 to 1 and vice versa.

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To estimate the bandwidth for the NRZ-L scheme using the average number of changes in the signal level, we can observe the number of transitions in the graphs. Each transition represents a change in the signal level. We count the transitions in each graph.

a. 00000000: 0 transitions (no change)
b. 11111111: 0 transitions (no change)
c. 01010101: 4 transitions
d. 00110011138: 8 transitions

By comparing the average number of changes in the signal level with the corresponding entry in Table 4.1, we can estimate the bandwidth for the NRZ-L scheme.

For the NRZ-I (Non-Return to Zero Inverted) scheme, the signal level changes its polarity (inverts) for each 1, and remains the same for consecutive 0s. The last signal level is assumed to be positive.

To draw the graph of the NRZ-I scheme, we represent the signal levels as either positive or negative voltages, depending on the input data stream.

a. 00000000:
In NRZ-I, the signal level remains the same (positive voltage) for consecutive 0s. Therefore, the graph for this data stream would be a flat line at a positive signal level.

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b. 11111111:
In NRZ-I, the signal level changes its polarity (alternates between positive and negative voltages) for consecutive 1s. Therefore, the graph for this data stream would alternate between positive and negative signal levels.

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c. 01010101:
In NRZ-I, the signal level changes its polarity (alternates between positive and negative voltages) for consecutive 1s, and remains the same (positive voltage) for consecutive 0s. Therefore, the graph for this data stream would alternate between positive and negative signal levels, with flat lines for consecutive 0s.

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d. 00110011138:
In NRZ-I, the signal level changes its polarity (alternates between positive and negative voltages) for consecutive 1s, and remains the same (positive voltage) for consecutive 0s. Therefore, the graph for this data stream would alternate between positive and negative signal levels, with flat lines for consecutive 0s.

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_________| |_____
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_
______________| |_____
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To estimate the bandwidth for the NRZ-I scheme using the average number of changes in the signal level, we count the transitions (changes in polarity) in each graph.

a. 00000000: 0 transitions (no change)
b. 11111111: 8 transitions
c. 01010101: 4 transitions
d. 00110011138: 14 transitions

By comparing the average number of changes in the signal level with the corresponding entry in Table 4.1, we can estimate the bandwidth for the NRZ-I scheme.