Question

4.4-4 Find LSR (t) and USB (1) for the modulating signal m(t) = 7B sinc (27 BI) with B = 2000 Hz and carrier frequency fe = 10,000 Hz. Follow these steps: (a) Sketch spectra of m(t) and the corresponding DSB-SC signal 2m(t) cos wcl. (b) To find the LSB spectrum, suppress the USB in the DSB-SC spectrum found in part (a). (c) Find the LSB signal LSB (t), which is the inverse Fourier transform of the LSB spectrum found in part (b). Follow a similar procedure to find puse (t).

Answer 1

E soll given that que have to find fuse (t) and Desblt) for the modelabing signat mCt) = mo sin cod (2.ABL ) with B - 2000 Hz Concies faequening (fe) = 10,000 HZ... @ using focniej tachofanm peris Brincº (hot) za 1. ) we have m(t) =B sin" (25 ) | m(t) = 7014611 and that can be drawn cus: THCA) YOU 40000 yooo yooo st en CH = Cos (en fet) =" (f = fe]++CH #fe). re duse () = m(t-10000) + HCl+10000)

usel) --fat - -14k rok ook o ok lok 14k ? suppressing the uso Spectrum the corres pending LSB spectrum is drawn. -14k alok 6ko ok lox 142 © Sujpresing the SB spektrum the corres pending Se- Spectrum is drawn in posolf) A -lyik ok . ook o ok ok 14k

Nou cue find the inverse founiey transforming éif uses and Le spectar. f PLSBLt) = f Polt) i fent of 4000 Ek' 1000 , e -lo + Cos (20060 AL)-cus (12000 TE:) CoOo Lý please led = () fart, 4000 . .. lok. 1000 Cos (qvodont)-cos (èsvoont) 8000 ntv. in