Question
A signal of 5 kHz frequency is amplitude modulated on a carrier wave of frequency 2 MHz. The frequencies of the resultant signal is/are:
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2005 kHz, and 1995 kHz
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2005 kHz, 2000 kHz and 1995 kHz
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2000 kHz and 1995 kHz
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2 MHz only
Solution
C.
2000 kHz and 1995 kHz
Frequency associated with AM are
fc - fm, f, fc + fm
according to the question
fc = 2 MHz = 2000 kHz
fm = 5 kHz
Thus, frequency of the resultant signal is are carrier frequency fc = 2000 kHz, LSB frequency fc-fm = 2000 kHz-5kHz = 1995 kHz and USB frequency fc+fm = 2005 kHz
Thus, frequency of the resultant signal is are carrier frequency fc = 2000 kHz, LSB frequency fc-fm = 2000 kHz-5kHz = 1995 kHz and USB frequency fc+fm = 2005 kHz
