ArticlePDF Available

Device for encoding/decoding N - bit source words into corresponding M - bit channel words, and vice versa

Authors:

Abstract

A device for encoding a stream of data bits of a binary source signal (S) into a stream of data bits of a binary channel signal (C), wherein the bit stream of the source signal is divided into n-bit source words (x1, x2), which device includes a converting circuit (CM) adapted to convert the source words into corresponding m-bit channel words (y1, y2, y3). The converting circuit (CM) is further adapted to convert n-bit source words into corresponding m-bit words, such that the conversion for each n-bit source word is parity preserving (table I). The relations hold that m>n, p>0, and that p can vary. Preferably, m=n+1. Further, a decoding device is disclosed for decoding the channel signal obtained by means of the encoding device.
United States Patent
[19J
Kahlman et al.
[54]
DEVICE
FOR
ENCODING/DECODING N-BIT
SOURCE WORDS
INTO
CORRESPONDING
M-BIT CHANNEL WORDS, AND
VICE
VERSA
[75]
Inventors: Josephus A.
H.
M. Kahlman; Kornelis
A.
Schouhamer
Immink,
both
of
Eindhoven, Netherlands
[73]
Assignee: U.S. Philips Corporation, New York,
N.Y.
[21]
Appl. No.: 223,875
[22]
Filed: Apr. 6, 1994
[30]
Foreign Application
Priority
Data
May 4,
1993
[EP]
European Pat. Off ............... 93201264
[51]
Int.
Cl.6
......................................................
H03M
7/00
[52]
U.S. Cl ................................................................. 341/95
[58]
Field
of
Search .................................. 341/95, 68, 69,
341/67, 58; 360/48,
51
[56]
References Cited
U.S. PATENT DOCUMENTS
4,337,458 6/1982 Cohn
et
al .............................. 340/347
4,547,890 11/1985 Gindi ........................................ 375/19
x,
x2
x3
1 , ,
I 1 '2 '3
r
i 1 '2 '3
LC'-
I'--
o,
02
03
04
8
1
~
,,
, ,
c
y1
y2 y3 y4
..
,...,
,__r
4
lllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllll
US0054 77222A
[11]
Patent Number:
[45]
Date of Patent: 5,477,222
Dec.
19,
1995
OTHER PUBLICATIONS
"Coding Techniques for Digital Recorders" by K.
A.
Schou-
harner Immink, Chapter 5.6.7,
pp.
127
to
131, Prentice Hall
(1991).
Bell System Technical Journal, "Spectrum
of
a Binary
Signal Block Coded for DC Suppression", vol. 53, No.6, pp.
1103-1106, 1974.
Primary Examiner-Brian K. Young
Attorney, Agent, or
Firm-Edward
W.
Goodman
[57]
ABSTRACT
A device for encoding a stream
of
databits
of
a binary source
signal
(S)
into a stream
of
databits
of
a binary channel signal
(C), wherein the bitstream
of
the source signal
is
divided
into n-bit source words (x1, x2
),
which device includes a
converting circuit (CM) adapted
to
convert the source words
into corresponding m-bit channel words
(y
1, y2, y3
).
The
converting circuit (CM) is further adapted to convert n-bit
source words into corresponding m-bit words, such that the
conversion for each n-bit source word is parity preserving
(table I). The relations hold that
m>n~
1,
p~
1,
and that p can
vary.
Preferably, m=n+
1.
Further, a decoding device is
disclosed for decoding the channel signal obtained by means
of
the encoding device.
11
Claims, 3 Drawing Sheets
2'
~
l
x4
s
-
~
D1
I
'4 (
10
""
..
~
..
..
..
..
....
, J
.
'4
12
CM'
lJ
05
06
,,
y5
Ys
... minimizes the DC contents [8, §11.4.3], [9], [11], [12], [13], [16]. ...
... , r − 1} is said to be admissible for (n 0 , n 1 , r) if there exists a nonnegative integer pair (η, ω) with r = r(η, ω) = r that satisfies K + = K − = 0 yet violates (9) when (and only when) ℓ ∈ Z. The inequalities (9) are then said to be independent if every subset Z ⊆ {1, 2, . . . , r − 1} is admissible for (n 0 , n 1 , r). ...
Preprint
Previous work by the authors on parity-preserving fixed-length constrained encoders is extended to the variable-length case. Parity-preserving variable-length encoders are formally defined, and, to this end, Kraft conditions are developed for the parity-preserving variable-length setting. Then, a necessary and sufficient condition is presented for the existence of deterministic parity-preserving variable-length encoders for a given constraint. Examples are provided that show that there are coding ratios where parity-preserving variable-length encoders exist, while fixed-length encoders do not.
... One implementation of this strategy uses parity-preserving encoders, whereby the parity (i.e., the modulo-2 sum) of the input sequence within nonoverlapping windows (each consisting of one or more pblocks) is preserved at the output. DC control can be achieved by reserving one input bit in that window and selecting its value so as to minimize the DC contents [9, §11.4.3], [10], [14], [15], [16], [18]. Parity-preserving RLL codes are used in the Blu-ray standard. ...
... The boxes at the bottom row are 1/n b units wide and represent the terminal states of the edges. The respective elements of ∆ b (u) are written just below the bottom row, where we have also shown their grouping into the subsets (8) defined by (10). The double vertical lines group the edges according to their labels. ...
Preprint
Necessary and sufficient conditions are presented for the existence of fixed-length parity-preserving encoders for a given constraint. It is also shown that under somewhat stronger conditions, the stethering method guarantees an encoder that has finite anticipation.
... The scheme requires definitely less complexity than the conventional schemes, and the performance loss is not noticeable in the range investigated. For displaying certain application of the proposed criteria, we apply the proposed criteria to 2/3(1, 7) parity preserving (PP) code [7], and GS scheme satisfying RLL constraints. For better DC-control of (1, 7) PP code, its encoding exploits look ahead (LA) algorithm that looks ahead some codewords. ...
... Parity preserving (PP) means that the modulo-2 addition of a source word (the "parity") is always equal to that of the corresponding channel word. The mapping rule of 2/3 (1, 7) PP code used in this paper is based on the second Table of [7]. This paper uses look ahead (LA) algorithm for better DC-control of (1, 7) PP code. ...
Article
Full-text available
DC-free run-length limited codes have been the cornerstone of all three generations of optical recording, CD, DVD and BD. Research into very efficient coding methods is paramount for the upcoming fourth generation. Guided Scrambling (GS) is an efficient coding method that has been reported in the literature. Under GS rules, a user word is translated into a plurality of possible candidate words, and among the candidate words the encoder selects the codeword with the least low-frequency spectral content. In our paper, we will present results of our attempts to improve the performance of GS-based codes. We will present new selection criteria and evaluate their performance and complexity. Specifically, we will evaluate the new selection criteria to the 2/3(1,7) parity preserving code used in Blu-Ray Disc.
... The scheme requires definitely less complexity than the conventional schemes, and the performance loss is not noticeable in the range investigated. For displaying certain application of the proposed criteria, we apply the proposed criteria to 2/3(1, 7) parity preserving (PP) code [7], and GS scheme satisfying RLL constraints. For better DC-control of (1, 7) PP code, its encoding exploits look ahead (LA) algorithm that looks ahead some codewords. ...
... L code, it shows the performance loss even if it has the acceptable performance at critical frequency for optical recording. We can conclude that GS scheme satisfying RLL constraints can clearly construct the DC-free code with small rate loss even if it uses RLL code with large DCcontent , and thus it is a promising candidate for optical recording. [7]. This paper uses look ahead (LA) algorithm for better DC-control of (1, 7) PP code. Encoding step of (1, 7) PP code using n LA algorithm is processed as follows. The scheme primarily inserts n+1 DC-control bits in the bitstream of the n+1 source words at regular interval. Then, it generates the two tree structure consisting of 2 n possi ...
Conference Paper
This paper proposes new criteria MPRDS (Minimum Peak Running Digital Sum with Sign Change) and ABSRDS (Absolute Running Digital Sum) schemes for evaluating the quality of candidate codewords in multimode codes. The schemes have similar performance and much simpler complexity compared to MSW (Minimum Squared Weight), which is known to be the best. In addition, this paper also introduces MTO/SC (Minimum Threshold Overrun with Sign Change) and MRDS/SC (Minimum Running Digital Sum with Sign Change) criteria. The MTO/SC and MRDS/SC are the improved versions of conventional MTO and RDS, respectively.
... The modulation coding (17PP) adopted by Blu-ray Disc system gives advantages in DC control (absence of merging bits) and the wider timing window in the eye pattern [3], [4]. The read-channel in optical recording is characterized by a modulation transfer function (MTF) with almost linear roll-off, and a cut-off frequency at (2NA)/λ [1]. ...
Article
Full-text available
This paper presents the system design of double-layer Blu-ray Disc recorders built in Philips Research Laboratory. The system architecture, new components, and the advanced signal processing are addressed. The experimental results show that writing HDTV programs to double-layer Blu-ray Discs and reading them back have been achieved. In addition, this paper demonstrates that discs with higher density and higher capacity are possible with the advanced technologies developed.
Article
Previous work by the authors on parity-preserving fixed-length constrained encoders is extended to the variable-length case. Parity-preserving variable-length encoders are formally defined, and, to this end, Kraft conditions are developed for the parity-preserving variable-length setting. Then, a necessary and sufficient condition is presented for the existence of deterministic parity-preserving variable-length encoders for a given constraint. Examples are provided that show that there are coding ratios where parity-preserving variable-length encoders exist, while fixed-length encoders do not.
Article
Bi-modal (respectively, multi-modal) constrained coding refers to an encoding model whereby a user input block can be mapped to two (respectively, multiple) codewords. In current storage applications, such as optical disks, multi-modal coding allows to achieve DC control, in addition to satisfying the runlength limited (RLL) constraint specified by the recording channel. In this work, a study is initiated on bi-modal fixed-length constrained encoders. Necessary and sufficient conditions are presented for the existence of such encoders for a given constraint. It is also shown that under somewhat stronger conditions, one can guarantee a bi-modal encoder with finite decoding delay.
Chapter
Modulation codes such as runlength-limited codes have been widely employed in magnetic and optical data storage systems. We review the main techniques involved in the design and use of these codes: the maximal code rate or capacity, graphical presentations of constraints, encoders and decoders, and code construction methods such as the ACH state-splitting algorithm. We conclude this survey by discussing some recent developments and research trends.
ResearchGate has not been able to resolve any references for this publication.