Energy per Bit required for Transmission in ASK, FSK, and PSK

Energy per Bit (Eb) for ASK

In the case of ASK modulation scheme the electric signal used is OFF-ON keying. The distance between the signalling points is √Eb as shown in the figure of the constellation diagrams of ASK, FSK, and PSK.

For Tramasion of binary bit '1', required enery is (√Eb)²

= Eb

For Transmission of binary '0', required energy is 0 as we use OFF-ON keying for transmission of ASK modulated signal.

 

The distance between the signalling points in the case of Binary ASK is √(Eb)

 

 

 

 

 

 

 Fig: Constellation Diagrams of ASK, FSK, and PSK

 

Energy per Bit (Eb) for FSK

** for transmission of binary '1'

Energy = (√Eb)² = Eb

** for transmission of binary '0'

Energy =  (√Eb)² = Eb

 For BFSK (orthogonal)

The distance between the signalling points in the case of FSK is √(2Eb)

Energy per Bit (Eb) for PSK

Energy required for transmission of binary '1' and '0' are as same as FSK but they differ in the orientations of the corresponding constellation diagrams because they are antipodal instead of orthogonal.  

 

The electrical signal representation technique  of BPSK is

1 = +ve

0 = -ve

 

 The distance between the signalling points in the case of BPSK is 2*(√Eb) For more clearity view the figure of constellation diagrams of ASK, FSK, and PSK.

 

Further Reading

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