Double sideband suppressed carrier (dsb sc) modulation

Double sideband suppressed carrier (dsb sc) modulation

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  DOUBLE SIDEBAND SUPPRESSED CARRIER (DSB-SC) MODULATION
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  PRESENTER: Hassan ijaz Quaid IAzam University Islamabad
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  DEFINITION: • DSB-SC isan amplitude modulated wave transmission scheme in which only sidebands are transmitted and the carrier is not transmitted as it gets suppressed. DSB-SC is an acronym for Double Sideband Suppressed Carrier.
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  GENERATION OF DSB-SCSIGNAL
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  CONTINUE • observing thefigure, we can say that a product modulator generates a DSB-SC signal. • The signal is obtained by the multiplication of baseband signal x(t) with carrier signal cos ωct
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  FREQUENCY SHIFTING PROPERTYOF FOURIER TRANSFORM- From the above equation, it is clear that only 2 components are present in the spectrum. These two are the two sidebands that are placed at +ωc and -ωc.
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  MATHEMATICAL EXPRESSION • Inorder to get an exact an idea about the suppression of carrier in DSB-SC system. • Consider the baseband or modulating signal, • x(t) = Ax cos (2πfxt) • and the carrier signal, • c(t) = Ac cos (2πfct)
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  CONTINUE The mathematical representationof the signal at the output of the product modulator is given as- s(t) = x(t).c(t) Further, The maximum frequency is fc + fx The minimum frequency is fc – fx
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  ADVANTAGES • of DSB-SCmodulation 1.It provides 100% modulation efficiency. 2.Due to suppression of carrier, it consumes less power. 3.It provides a larger bandwidth.
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  DISADVANTAGES • of DSB-SCmodulation 1.It involves a complex detection process. 2.Using this technique it is sometimes difficult to recover the signal at the receiver. 3.It is an expensive technique when it comes to demodulation of the sign
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  APPLICATIONS OF DSB-SCMODULATION 1.During the transmission of binary data, DSB-SC system is used in phase shift keying methods. 2.In order to transmit 2 channel stereo signals, DSB signals are used in Television and FM broadcasting. • DSB-SC technique allows us to have a transmission that reduces overall power consumption rate, thereby ensuring a stronger signal at the output.