In the circuit shown below between the terminal A and B

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In the circuit shown below between the terminal A and B an a.c. voltage source of frequency 400 Hz is connected. Another a.c. voltage of 1.0 MHz is connected between C and D. The output between E and F contains components at—

1. 400 Hz, 1MHz, 1000·4 kHz, 999·6 kHz
2. 1 MHz, 1000·4 kHz, 999·6 kHz
3. 400 Hz, 1000·4 kHz, 999·6 kHz
4. 1000·4 kHz, 999·6 kHz

Correct Option: D

The given circuit represents ring modulator. In ring modulator the output is proportional to the product of two i.e., m(t) and c(t) → DSB-SC signal
Here, m(t)=Am cos (2π × 400t)
= A_m (cos 2π × 0·4 × 10³t)
So the output s(t) = m(t )·c(t), contains components at frequency
f_c ± f_m
or (1000 ± 0·4) kHz or 1000·4 kHz and 999·6 kHz
Hence alternative (D) is the correct choice.