notes-offset-qpsk-carrier-recovery

notes-offset-qpsk-carrier-recovery - Notes:ECE513

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Notes: ECE 513 Digital and Data Communications 1 Prepare by:  Jan Ray Rulida, ECE Offset QPSK (OQPSK) - is a modified form of QPSK where the bit waveforms on the I and Q channels are offset or shifted in phase from  each other by one-half of a bit time 8-PSK three bits are encoded, forming tribits and producing eight different output phases N=3  and  M=8 - it can be seen that the angular separation between any two adjacent phasors is 45° (half of what it    is with QPSK) - an 8-PSK signal can undergo almost a  ± 22.5° phase shift during transmission and still retain its integrity - the tribit code between any two adjacent phases changes by only one bit; this type of code is called the  Gray  code  or, sometimes, the  maximum distance code . - Gray code is used to reduce the number of transmission errors. Bandwidth Considerations: The bitrate in the I, Q, or C channel is equal to one-third of the binary input data rate ( f b /3) 16-PSK - is an  M-ary  encoding technique where  M=16 ; there are 16 different output phases possible. - four bits (quad bits) are combined, producing 16 different output phases
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This note was uploaded on 11/10/2011 for the course COMPUTER E 444 taught by Professor Amigo during the Fall '10 term at Al-Quds University.

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notes-offset-qpsk-carrier-recovery - Notes:ECE513

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