A The Carrier Frequency C 125 Khz And B The

Consider a message signal m (t) with the spectrum shown in Figure. The message bandwidth W = 1 kHz. This signal is applied to a product modulator, together with a carrier wave Ac cos (2πƒct), producing the DSB-SC modulator signal s (t). The modulated signal is next applied to a coherent detector. Assuming perfect synchronism between the carrier waves in the modulator and detector, determine the spectrum of the detector output when:

(a) The carrier frequency ƒc = 1.25 kHz and

(b) The carrier frequency ƒc = 0.75 kHz. What is the lowest carrier frequency for which each component of the modulated signal s (t) is uniquely by m (t)?

(a) The carrier frequency Æ’c = 1.25 kHz and (b) The

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