An AM wave10[1 + 0·6 cos 2π 103t] cos 2π 106t is to be

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An AM wave
10[1 + 0·6 cos 2π 10³t] cos 2π 10⁶t
is to be detected by a linear diode detector, the value of the time constant is—

1. 0.17 ms
2. 1.7 ms
3. 0.212 ms
4. None of these

Correct Option: C

The given AM wave is
s(t) = 10[1 + 0·6 cos 2π 10³t] cos 2π 10⁶t
Here μ = 0·6 and ω_m = 2π·10³
The required condition for the detector output is to follow the envelop all the times is

RC ≤	1	√	1 − μ²
	ω_m		μ²

RC ≤	1	√	1 − (0.6)²
	2π10³		(0.6)²

or τ ≤ 0.212 ms
or

RC ≤	1.33
	2π10³

Hence alternative (C) is the correct choice.