# Why do we need bit scrambling when using 8b/10b?

I want to ask the opposite of this question.

Here are the purpose of the bit scramblers:

• Encrypt, but LFSR (and other used) bit-scramblers are breakable.
• Clock recovery, but it is done by the 8b/
• DC offset, but it is done by the 8b/10b.
• (Are there any?)

Why do we need bit scrambling when using 8b/10b?

• Scrambling improves resistance to loss of several bits in a row, due to a single noise event? – tomnexus Oct 11 '18 at 10:22
• @tomnexus I don't believe so. For example, CRCs can detect longer burst sequences than distributed errors. It would help for distributing burst errors between separate data blocks (such as used in CD-ROMs) but in such situation there is no advantage to scrambling - you can just use a fixed interleaving pattern. Might be some form of error detection/recovery I am overlooking though. – Jon Oct 11 '18 at 10:31

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