Exam-style question
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A timing diagram shows three channels A, B and C sharing a single transmission line. The diagram consists of a repeating cycle of three equal time slots. In slot 1, channel A transmits a data burst; in slot 2, channel B transmits; in slot 3, channel C transmits. A sync pulse is shown at the start of each cycle. Interpret the diagram and explain how the data from the three channels is transmitted over the shared medium.
Model answer
What a good answer should say
- The diagram illustrates time‑division multiplexing.
- Each channel is assigned a distinct time slot within a repeating cycle, so only one channel transmits at any instant.
- The sync pulse marks the beginning of each cycle, allowing receivers to align their sampling windows.
- Thus the shared medium carries the three data streams sequentially, one after the other, without overlap.
Explanation
Why this works
evidence: a timing diagram with three equal time slots, each occupied by a different channel and a sync pulse at the start of each cycle; interpretation: the diagram shows that each channel transmits in its own slot, demonstrating time‑division multiplexing; implication: this implies that the shared medium can carry multiple data streams sequentially, with the sync pulse ensuring correct alignment; conclusion: the question tests the student’s ability to interpret a TDM timing diagram and explain the role of time slots and sync pulses.
Common mistake
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