Question

4. [20 points] Two signals m(t) and m-(t), both band-limited to 5000 Hz, are to be transmitted simultaneously over a channel by the multiplexing scheme shown in the following figure. The signal at point b is the multiplexed signal, which now modulates a carrier of frequen Hz. The modulated signal at point c is transmitted over a channel cy 20,000 15 points] Sketch signal spectra at points a, b, and c. [10 points] Design a receiver to recover signals ma(t) and ma(t) from the modulated signal at point e. Draw a block diagram and s 1) 2) aw a block diagram and sketch spectra showing the received signal at the receiver you designed can be successfully demodulated [5 points] Is this scheme similar to FDM (Frequency Division Multiplexing), TDM (Time Division Multiplexing), or CDM (Code Division Multiplexing)? 3) MI 5000 0 500of 220t) ct 2 cos 40,000 2 cos 20,000 Figure 3: An analog scrambling system For full credit, label frequencies and magnitudes of the spectra for the sketches.

Two signals m1(t) and m2(t), both band-limited to 5000 Hz, are to be transmitted simultaneously over a channel by the multiplexing scheme shown in the following figure.The signal at point b is the multiplexed signal, which now modulates a carrier of frequency 20,000 Hz. The modulated signal at point c is transmitted over a channel.

Answer 1

qiven that The spedtum at point a is 15000 100005 5000 0 B Cf) -15010 ๛10,000-5000 0 5000 100 15000

B(+-2.00 cct) 3500 -5 to 500, !S0o» 20000 25000 35050 2. The tol Loucin Bond pass fitte 20000 natt) -1S000 -S0 500 5o0

epF M、(f , 5000 -5000 5000 5000 Yo m tths bound odt