Assertion–Reason: Artificial transmission line as a pulse generator Assertion (A): An artificial (lumped) transmission line can be used as a pulse generator (pulse-forming network). Reason (R): A pulse function is used very frequently in network analysis.
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ABoth A and R are correct and R is the correct explanation of A
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BBoth A and R are correct but R is not the correct explanation of A
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CA is correct but R is wrong
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DA is wrong but R is correct
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EBoth A and R are wrong
Answer
Correct Answer: Both A and R are correct but R is not the correct explanation of A
Explanation
Introduction / Context:Artificial transmission lines (pulse-forming networks, PFNs) are cascaded L–C sections that emulate the delay and impedance of a real line. When charged and discharged through a switch into a matched load, they generate rectangular pulses with controlled width and amplitude, widely used in radar modulators and pulsed power systems.
Given Data / Assumptions:
- An artificial line approximates Z0 and propagation delay with lumped L and C.
- When properly switched into Z0, it produces a flat-top pulse until the stored energy is depleted.
- Network analysis often employs pulse or step functions for system characterization.
Concept / Approach:
The validity of A: A PFN charged to V and suddenly connected to a matched load Z0 discharges to produce a pulse approximately of amplitude V/2 (for certain topologies) and duration determined by the line’s electrical length. This is a standard pulse generation method independent of any analytic preference. The truth of R: Pulse functions are indeed used frequently for analysis, but that fact does not explain why an artificial line works as a pulse generator; the explanation rests on energy storage and transmission-line matching, not on mathematical usage of pulses.
Step-by-Step Solution:
1) Synthesize an L–C ladder with Z0 and delay τ.2) Charge to V using a DC source.3) Close a switch to a matched load → pulse of width ≈ 2τ and controlled amplitude.Verification / Alternative check:
Time-domain analysis of ladder networks shows uniform current/voltage segments during discharge into Z0, matching pulse-forming behavior.
Why Other Options Are Wrong:
Option A: claims R explains A, which is incorrect causality; options C/D/E deny one or both truths contrary to standard PFN practice.
Common Pitfalls:
Confusing pulse analysis with pulse generation; overlooking the requirement of matching the load to Z0 for a flat pulse.
Final Answer:
Both A and R are correct but R is not the correct explanation of A.