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)