About PN Sequence Generation (Flex Frame)
A PN 1) part number, or 2) packet number (pseudo noise) sequence simulates the random characteristics of a digital signal and can be generated for both the measured signal and the reference signal for BER Bit Error Ratio - A ratio of the number of errors to data bits received on a digital circuit. measurements. The PN sequences generated by Flex Frame Modulation Analysis conform to CCITT T-REC-O.151 (PN15 and PN23) and T-REC-O.153 (all other PNs).
For all PN sequences, the VSA software assumes the register is shifted from right to left. The MSB Most significant bit. In a binary coding scheme, the bit having the greatest numerical value. Analogous to the left-most numeric position in a decimal number. (most significant bit) is shifted out as the output bit.
PN9
Characteristic polynomial
P(x) = x9 + x5 + 1
Seed
For PN9, the seeds of the shift registers are all 1s.
Potential output bit-inversion
There is no bit inversion for the PN9 sequence.
PN11
Characteristic polynomial
P(x) = x11 + x9 + 1
Seed
For PN11, the seeds of the shift registers are all 1s.
Potential output bit-inversion
There is no bit inversion for the PN11 sequence.
PN15
Characteristic polynomial
P(x) = x15 + x14 + 1
Seed
For PN15, the seeds of the shift registers are all 1s except for the first 15 bits, which are inverted from all 1s to all 0s.
Potential output bit-inversion
The first 15 bits are inverted from all 1s to all 0s for PN15.
PN20
Characteristic polynomial
P(x) = x20 + x3 + 1
Seed
For PN20, the seeds of the shift registers are all 1s.
Potential output bit-inversion
There is no bit inversion for the PN20 sequence.
PN23
Characteristic polynomial
P(x) = x23 + x18 + 1
Seed
For PN23, the seeds of the shift registers are all 1s except for the first 23 bits, which are inverted from all 1s to all 0s.
Potential output bit-inversion
The first 23 bits are inverted from all 1s to all 0s for PN23.
See Also
