Browse Prior Art Database

Interleaved Encoding Method for Trellis Codes

IP.com Disclosure Number: IPCOM000104581D
Original Publication Date: 1993-May-01
Included in the Prior Art Database: 2005-Mar-19
Document File: 2 page(s) / 51K

Publishing Venue

IBM

Related People

Christiansen, GS: AUTHOR [+2]

Abstract

A method for interleaving successive encoded data words is disclosed. The method requires only one encoder and introduces no gaps into the output record.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 64% of the total text.

Interleaved Encoding Method for Trellis Codes

      A method for interleaving successive encoded data words is
disclosed.  The method requires only one encoder and introduces no
gaps into the output record.

      Fig. 1 shows the circuit used to encode the customer data and
interleave the encoded bytes.  The customer bytes arrive sequentially
in time.  Each successive pair of consecutive customer 8-bit bytes of
data are separately encoded into two bytes with an 8/10 rate code (a
code where 8 input customer bits result in 10 encoded bits), giving a
pair of codewords, i.e., E9E8E7E6E5E4E3E2E1E0 and
F9F8F7F6F5F4F3F2F1F0, respectively.  This circuit interleaves these
successive encoded bytes, giving E9F9E8F8E7F7 ...E0F0 as the final
output.

      In Fig. 1, U, X, Y, and Z are multibit latches.  The customer
bytes arrive sequentially in time and are latched by the byte clock
into latch U.  The output of latch U is encoded, and the result is
stored in latch X at the next clock.  This encoded byte is stored in
latch Y on the next clock, and latch Z on the clock after that.
Combinatorial logic is used to select the proper bits for the output
from latches X, Y, and Z.

      The timing diagram in Fig. 2 illustrates the encoding of four
consecutive bytes:

      A7A6A5A4A3A2A1A0  = >  E9E8E7E6E5E4E3E2D1E0

      B7B6B5B4B3B2B1B0  = >  F9F8F7F6F5F4F3F2F1F0

      C7C6C5C4C3C2C1C0  = >  G9G8G7G6G5G4G3G2G1G0

      D7D6D5D4D3D2D1D0  = > ...