Types of Conversions Cont

o    NRZ-L ƒ     Level of the signal depends on the type of bit it represents ƒ     A +ve voltage usually means the bit is a 1 and a -ve voltage means the bit is a 0 (vice versa) ŠProblem  with  NRZ-L:  When  long  streams  of  0's  or  1's  are  there  in data,  Rx  receives  a  continuous  voltage  and  should  determine  how  many bits   are   sent   by   relying   on   its   clock   ,   which   may   or   may   not   be synchronized with the sender clock o    NRZ-I ƒ     The inversion of the level represents a 1 bit ƒ     A bit 0 is represented by no change ƒ     NRZ-I is superior to NRZ-L due to synchronization provided by signal change each time a 1 bit is encountered ƒ     The string of 0's can still cause problem but since 0's are not as likely, they are less of a problem