EP0280549A2
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Data compression method and apparatus
Assignee: Oki Electric Industry Co Ltd
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Filing: 1988-02-25
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Granted: —
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Expires: 2008-02-25
Abstract
Abstract Text data (sentences, programs) is compressed for transmission between computers or terminals. A transmitting terminal (11) inputs words to searching means (14). A dictionary (15) which stores words already entered is searched, and a corresponding codeword transmitted through a modulator (18). An occurrence frequency calculator (17) assigns a shorter codeword to an input word if its frequency rises. New word entry means (16) makes entries in the dictionary (15). The dictionary (15) may contain pseudowords one or two characters in length. A receiving end is similar.
Inventors
- 👤 Takuro Oki Electric Industry Co. Ltd. Sato
- 👤 Yoshihito Oki Electric Industry Co. Ltd Shimazaki
- 👤 Manabu Oki Electric Industry Co. Ltd Kawabe
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-27 12:58
CPC Classifications
H; H03; H03M; H03M7/00; H03M7/30; H03M7/40; H03M7/42; G; G06; G06F; G06F40/00; G06F40/10; G06F40/12
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
52 words
A method of compressing text data which comprises searching a dictionary (15) for an input word and producing a corresponding codeword if it is found in the dictionary (15) characterized by calculating the occurrence frequency of the input word, and if that frequency rises assigning a shorter codeword to the input word.
Claim 2
Independent Claim
52 words
A method of compressing text data which comprises searching a dictionary (15) for an input word and producing a corresponding codeword if it is found in the dictionary (15) characterized by calculating the occurrence frequency of the input word, and if that frequency rises assigning a shorter codeword to the input word.
Claim 3
Dependent Claim
17 words
A method according to claim 1 in which a new word is entered in the dictionary (15).
Claim 4
Dependent Claim
38 words
A method according to claim 1 or claim 2 in which the dictionary (15) contrains pseudowords, and if the searching finds no ordinary word, dividing the input word into pseudowords of fixed length and searching for the pseudowords.
Claim 5
Dependent Claim
17 words
A method according to claim 3 in which the pseudowords are one or two characters in length.
Claim 6
Independent Claim
24 words
A method according to any preceding claim in which a word or pseudoword having a low occurrence count is removed from the dictionary (15).
Claim 7
Dependent Claim
53 words
Apparatus for compressing text data which comprises means (14) for searching a dictionary (15) for an input word and sending a corresponding codeword to a modulator (18) characterized by an occurrence frequency calculator (17) for the input word means for assigning a shorter codeword to the input word if its occurrence frequency rises.
Claim 8
Dependent Claim
53 words
Apparatus for compressing text data which comprises means (14) for searching a dictionary (15) for an input word and sending a corresponding codeword to a modulator (18) characterized by an occurrence frequency calculator (17) for the input word means for assigning a shorter codeword to the input word if its occurrence frequency rises.
Claim 9
Dependent Claim
13 words
Apparatus according to claim 6 including means (16) for entering a new word.
Claim 10
Dependent Claim
18 words
Apparatus according to claim 6 or claim 7 including means (315) for dividing an input word into pseudowords.
References Cited (Backward Citations)
No citation records indexed.
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