EP0150082A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Method of transmitting information, encoding device for use in the method, and decoding device for use in the method
Assignee: Koninklijke Philips NV
•
Filing: 1985-01-18
•
Granted: —
•
Expires: 2005-01-18
Abstract
Abstract A method of converting n-bit information words into m-bit code words, and the other way round, is described. The code words have a limited disparity. For every information word two code words are assigned to a group of information words, which code words can be derived from one another by inversion. A choice between these two code words is made to limit the digital sum value so as to obtain a d.c. free code. In order to obtain a further limitation of the digital sum value within the code words these code words are derived from each other by inversion and reversal.
Inventors
- 👤 Kornelis Antonie Schouhamer Immink
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-01 09:36
CPC Classifications
G; G06; G06F; G06F13/00; G11; G11B; G11B20/00; G11B20/10; G11B20/14; G11B20/1403; G11B20/1423; G11B20/1426; H; H04; H04L; H04L25/00; H04L25/38; H04L25/40; H04L25/49; H04L25/4906
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
394 words
A method of transmitting information, in which n-bit information-words are converted into m-bit code words before transmission and said m-bit code words are re-converted into n-bit information words after transmission and in which for converting consecutive n-bit information words into m-bit information words with a limited maximum disparity ± d prior to transmission, where n, m and d are integers which comply with n < m and d < m, in such a way that the digital sum value taken over all the preceding code words at the beginning of a code word remains limited to a range which is bounded by a first and a second value, the following code word is selected, at least with respect to the polarity of the disparity, as a function of said digital sum value over all the preceding code words so as to ensure that said following code word cannot cause an increase of the absolute value of said digital sum value, for which purpose a pair of code words is assigned to at least a first group of possible n-bit information words, the code words of said pair having opposite disparities with an absolute value d and being the bit-by-bit inverse of one another for each associated information word, characterized in that for limiting the instantaneous digital sum value to a range which is bounded by a third and a fourth value, which third and which fourth values are situated outside the range bounded by the first and the second value in such a way that the spacing between the second and the fourth value is smaller than the spacing between the third and the first value, first and second code words with a disparity +d and -d, respectively are assigned to at least a part of the first group of code words, which second code words of said part of the first group for every associated information word are the bit-by-bit inverses of the first code words whose transmission sequence has been reversed, said first code words having been selected from at least that group of code words which in conformity with said selection rule remain within the range which is bounded by the third and the fourth value, whilst the corresponding bit-by-bit inverted code word does not remain within said range and after reversal of the transmission sequence does remain within said range.
Claim 2
Independent Claim
394 words
A method of transmitting information, in which n-bit information-words are converted into m-bit code words before transmission and said m-bit code words are re-converted into n-bit information words after transmission and in which for converting consecutive n-bit information words into m-bit information words with a limited maximum disparity ± d prior to transmission, where n, m and d are integers which comply with n < m and d < m, in such a way that the digital sum value taken over all the preceding code words at the beginning of a code word remains limited to a range which is bounded by a first and a second value, the following code word is selected, at least with respect to the polarity of the disparity, as a function of said digital sum value over all the preceding code words so as to ensure that said following code word cannot cause an increase of the absolute value of said digital sum value, for which purpose a pair of code words is assigned to at least a first group of possible n-bit information words, the code words of said pair having opposite disparities with an absolute value d and being the bit-by-bit inverse of one another for each associated information word, characterized in that for limiting the instantaneous digital sum value to a range which is bounded by a third and a fourth value, which third and which fourth values are situated outside the range bounded by the first and the second value in such a way that the spacing between the second and the fourth value is smaller than the spacing between the third and the first value, first and second code words with a disparity +d and -d, respectively are assigned to at least a part of the first group of code words, which second code words of said part of the first group for every associated information word are the bit-by-bit inverses of the first code words whose transmission sequence has been reversed, said first code words having been selected from at least that group of code words which in conformity with said selection rule remain within the range which is bounded by the third and the fourth value, whilst the corresponding bit-by-bit inverted code word does not remain within said range and after reversal of the transmission sequence does remain within said range.
Claim 3
Dependent Claim
61 words
A method as claimed in Claim 1, characterized in that after transmission of the code words it is checked whether they exhibit a disparity +d or -d, and code words belonging to said part of the first group of information words are converted directly or after bit-by-bit inversion and reversal of the transmission sequence, depending on the polarity of the disparity.
Claim 4
Dependent Claim
182 words
A method as claimed in Claim 1 or 2, characterized in that the maximum disparity I d is equel to the minimum possible disparity is unequal to zero, so that the digital sum value taken over all the preceding code words at the beginning of a code word remains limited to either the first value or the second value, which values are spaced from each other, and the first code words which belong to the first group of information words cause said digital sum value to vary from the first value to the second value, whilst the associatdd second code words cause said digital sum value to vary from the second value to the first value, a selection being made from the first code words to encode an information word of the first group if the digital sum value exhibits the first value at the beginning of the code word and the bit-by-bit inverse of the code word whose transmission sequence has been reversed being selected if the digital sum value exhibits the second value at. the beginning of the code word.
Claim 5
Dependent Claim
88 words
A method as claimed in Claim 3, characterized in that the maximum disparity ±d is equal to ±2 and code words of the disparity are assigned to a second group of information words, which code words are selected independently of the digital sum value at the beginning of the code word, which do not exceed the third value when they vary from the first value to the first value, and which do not exceed the fourth value when they vary from the second value to the second value.
Claim 6
Dependent Claim
45 words
A method as claimed in Claim 4, characterized in that n = 8 and m = 10 and the third value is situated at a spacing 2 from the first value and the fourth value is situated at & spacing 1 from the second value.
Claim 7
Dependent Claim
78 words
An encoding device for use in the method as claimed in any one of the preceding Claims, for converting n-bit information words into m-bit code words, characterized by:means for determining the digital sum value taken over all the preceding words, means for converting the information words of the first group, means for inverting and reversing the code words obtained by converting information words of the first group if this is required by the digital sum value thus determined.
Claim 8
Dependent Claim
80 words
A decoding device for use in the method as claimed in any one of the Claims 1 to 5, for converting m-bit code words into n-bit information words, characterized by: means for determining the disparity of the code words received, means for inverting and reversing the code words which correspond to information words of the first group if this is required by the disparity found, and means for converting the code words corresponding to information words of the first group.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.