What is suppressed carrier system?
What is suppressed carrier system?
Suppressed-carrier transmission is a special case in which the carrier level is reduced below that required for demodulation by a normal receiver. Carrier power must be restored by the receiving station to permit demodulation, usually by means of a beat frequency oscillator (BFO).
What does DSBSC modulation mean?
Double-sideband suppressed-carrier transmission (DSB-SC) is transmission in which frequencies produced by amplitude modulation (AM) are symmetrically spaced above and below the carrier frequency and the carrier level is reduced to the lowest practical level, ideally being completely suppressed.
How the carrier is suppressed in DSBSC modulation?
In the process of Amplitude Modulation, the modulated wave consists of the carrier wave and two sidebands. If this carrier is suppressed and the saved power is distributed to the two sidebands, then such a process is called as Double Sideband Suppressed Carrier system or simply DSBSC.
Which is better Dsbsc or Ssbsc?
DSB-SC – Double SideBand Suppressed Carrier As shown in the fig-4, DSB-SC spectrum has both the sidebands and no carrier is present. Hence it needs two times the bandwidth of SSBSC as explained later. It has advantages of having lower power consumption but needs complex detection at the receiver side.
What are the advantages of DSB transmission?
Advantages of DSB-SC modulation It provides 100% modulation efficiency. Due to suppression of carrier, it consumes less power. It provides a larger bandwidth.
What are the disadvantages of single sideband transmission?
The disadvantages of single-sideband modulation mainly include the following.
- The discovery & generation process of the single-sideband signal is complex.
- Signal quality will be affected when the transmitter & receiver of SSB have outstanding frequency strength.
What happens if the modulation index is higher than 100 %? Describe how do you avoid this?
If the level of modulation is raised up above a modulation index of 1, i.e. more than 100% modulation this causes what is termed over-modulation. The carrier experiences 180° phase reversals where the carrier level would try to go below the zero point. This will ensure that the carrier is not over-modulated.
Why is SSB preferred over DSB-FC or Dsbsc?
The advantages of SSB-SC over DSB-FC signal are : Less bandwidth requirements . This allow more number of signals to be transmitted in the same frequency range . Lots of power saving .
Why do we use double sideband suppressed carrier modulation?
As we know that transmission power and bandwidth are the two important parameters in a communication system. Thus, in order to save power and bandwidth, DSB-SC modulation technique is adopted. A normal system also termed as Double Sideband Full Carrier (DSB-FC) system, transmits carrier along with the two sidebands.
Why is suppression of carrier used in DSB-SC?
Due to suppression of carrier, it consumes less power. It provides a larger bandwidth. It involves a complex detection process. Using this technique it is sometimes difficult to recover the signal at the receiver. It is an expensive technique when it comes to demodulation of the signal.
How is coherent demodulation of DSB-SC signal done?
Demodulation For DSBSC, Coherent Demodulation is done by multiplying the DSB-SC signal with the carrier signal (with the same phase as in the modulation process) just like the modulation process. This resultant signal is then passed through a low pass filter to produce a scaled version of the original message signal.
Where does the name suppressed carrier come from?
The name “suppressed carrier” comes about because the carrier signal component is suppressed—it does not appear in the output signal. This is apparent when the spectrum of the output signal is viewed.