GATE 2026 EC Q.57: official answer

GATE 2026 · ECQ.57 · 2 marks · MSQ

Consider a real, narrowband signal $x (t) = A (t) cos [2 π f_{c} t + θ (t)]$ where the maximum frequency components of $A (t)$ and $θ (t)$ are $f_{M}$ and $f_{c} (= 1000 f_{M})$ , respectively. Which of the following statements is/are correct for $- \infty < t < \infty$ ?

(A)
$x (t)$ represents a PSK modulated signal for suitable choices of $A (t)$ and $θ (t)$ .
(B)
$x (t)$ represents an amplitude modulated signal for suitable choices of $A (t)$ and $θ (t)$ .
(C)
$x (t)$ represents a band-limited Gaussian noise process.
(D)
$x (t)$ never represents a narrowband FM signal.

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Official answer

Official answer: A, B, CSource: Official answer key, GATE 2026 EC (IIT Guwahati)

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GATE 2026 EC Q.57: official answer

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