Question
Download Solution PDFMultiplexing scheme which uses carrier phase shifting and synchronous detection to permit two DSB signals to occupy the same frequency band is called
Answer (Detailed Solution Below)
Detailed Solution
Download Solution PDFDigital to Analog Modulation technique is as shown.
Important Points
1) As shown, QAM is a mixture of both ASK and PSK.
2) QAM uses two carrier signals with the same frequency but with which are in quadrature. Quadrature here means out phase by 90°.
3) Since the two signals have the same frequency, they are detected using synchronous detection.
4) Hence, amplitude and the phase of the carrier frequency both vary with the message signal.
A constellation diagram of a QAM signal with 2 different amplitude levels and 8 different phases is shown:
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