POLAR ENCODING
POLAR ENCODING Polar encoding uses two levels ( positive and negative ) of amplitude. The polar encoding is catagorise into 3 types :- · NRZ(non return to zero) · RZ(return to zero) · Biphase Non Return To Zero (NRZ)- In NRZ encoding , The level of the signal is always either positive of negative . The NRZ encoding includes two methods :- · Non Return To Zero ,Level (NRZ-L) · Non Return To Zero ,Invert (NRZ-I) NRZ-L :- In NRZ-L encodingthe level of the signal depends on the type of bit it represents. § A positive voltage means the bit is 0 , and a negative voltage means the bit is 1 . § Thus the level of the signal is dependent upon the state of the bit. NRZ-I :- In NRZ-I , on inversion of voltage level represents a 1 bit. A 0 bit is represented by no change . NRZ-I is superior to NRZ-L due to the synchronization provided by signal change each time a 1 bit is
