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PARTIAL CORRELATION. M-sequence Autocorrelation. M-sequence Partial Correlation. 50 chips. PARTIAL CORRELATION (Cont.). 50 chips. 40 chips. 30 chips. 20 chips. PERIODIC VS. APERIODIC CORRELATION. 1. 4. 2. 3. PN Code Reference. Periodic. 1. PN Code Reference. Aperiodic.
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PARTIAL CORRELATION M-sequence Autocorrelation M-sequence Partial Correlation 50 chips
PARTIAL CORRELATION (Cont.) 50 chips 40 chips 30 chips 20 chips
PERIODIC VS. APERIODIC CORRELATION 1 4 2 3 PN Code Reference Periodic 1 PN Code Reference Aperiodic
APERIODIC AUTOCORRELATION Peak Value Approximately 15 side lobe values Index of discrimination G(x) = 45o
PARTIAL APERIODIC AUTOCORRELATION G(x) = 45o 15 Chips
CROSSCORRELATION([45]o and [75]o) Periodic Aperiodic
GOLD CODE CONSTRUCTION Code 1 LRS 1 + Clock LRS 2 Code 2 Output = Gold Code ( Code 1 xor Code 2)
+ + + 1 2 3 4 5 1 2 3 4 5 GOLD CODE CONSTRUCTION x5 + x3 + 1 = [51]o Gold Code x5 + x4 + x3 + x2 + 1 = [75]o
MAXIMUM NUMBER OF GOLD CODES n # of m-sequences. # of Gold Codes 5 6 31 + 2 6 4 63 + 2 7 18 127 + 2 8 16 255 + 2 9 48 511 + 2 . . . . . . . . . 15 1800 32767 + 2
Table A7.1 Performance of Preferred Pairs Compared with Worst Case Pairs
Table A7.3 Preferred Pairs for Gold Code Generation (Not complete List)
2m - 1 2n - 1 2p - 1 JPL CODE CONSTRUCTION a a xor b xor c b c