Modulation & demodulation, Assignments of Data Communication Systems and Computer Networks

Download Modulation & demodulation and more Assignments Data Communication Systems and Computer Networks in PDF only on Docsity! Modulation " ANALOG MODULATION " DIGITAL MODULATION Submitted to : Mam Sumaira Submitted by: Abdullah Akram Roll no: (28) Class: BSCS(4th) Topic : Use Case  Amplitude Modulation (AM) Amplitude modulation is a technique by which the amplitude of the carrier waves is changed according to the signal wave or modulating signal.  After changing carrier wave according to signal or modulating wave This amplitude modulating wave contain a time –varying amplitude that is termed as an envelops. This envelope has same shape as that of the message signal. I. The first image in the above figure shows the modulating signal that has to be transmitted from an end to other. II. The second one is the carrier wave, whose frequency is to be varied according to the amplitude of the message signal. III. The third image shows that the frequency modulated signal that is transmitted after modulation is hone. Phase modulation (pm)  Phase modulation is another type of angle modulation in which the phase of the carrier wave is changed according to the amplitude (magnitude) of the message (modulating) signal.  In phase modulation of an analog signal the phase change is a continuous back and fourth movement. While in case of digital signal there exist an abrupt change in the phase of carrier signal.  The phase modulation of the digital signal is generally known as phase shift keying. m(t) c(t) s(t) \ ! J \ J Y ¥ Carrier Carrier stretching compression (phase lag) (phase lead) _ Waveform for Phase Modulation _