US4701744A
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Method and apparatus for compacting and de-compacting text characters
Assignee: RCA Licensing Corp
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Filing: 1986-03-27
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Granted: 1987-10-20
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Expires: 2006-03-27
Abstract
Abstract A television receiver includes a micro-computer which controls the receiver functions and provides on-screen display of messages for prompting the user. Display characters are compacted to minimize memory space by encoding the characters in 4-bit nibbles to maximize storage efficiency in a ROM organized to store 8-bit bytes.
Inventors
- 👤 Warren C. DeVilbiss
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 21:01
CPC Classifications
G; G06; G06F; G06F12/00; H; H03; H03M; H03M7/00; H03M7/30
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
118 words
A method of compacting characters for storage, comprising: generating a sequence of four-bit characters in which some characters are of a first character set and other characters are taken from a second character set; inserting a given four-bit shift character not taken from either character set in said sequence of characters every time a character of either set is followed by a character of the other set; and storing said sequence of characters and said shift character in a memory means in which each memory address represents at least one pair of stored characters, each character of said at least one pair being selected from said first character set said second character set and said given shift character.
Claim 2
Independent Claim
118 words
A method of compacting characters for storage, comprising: generating a sequence of four-bit characters in which some characters are of a first character set and other characters are taken from a second character set; inserting a given four-bit shift character not taken from either character set in said sequence of characters every time a character of either set is followed by a character of the other set; and storing said sequence of characters and said shift character in a memory means in which each memory address represents at least one pair of stored characters, each character of said at least one pair being selected from said first character set said second character set and said given shift character.
Claim 3
Dependent Claim
17 words
A method as recited in claim 1 wherein said memory means stores said characters in 8-bit bytes.
Claim 4
Dependent Claim
18 words
A method as recited in claim 1 wherein said characters exclude the letters J, Q, X and Z.
Claim 5
Dependent Claim
25 words
A method as recited in claim 1 wherein there are 15 characters in said first character set and 15 characters in said second character set.
Claim 6
Dependent Claim
153 words
Apparatus for decompacting four-bit characters stored in a memory in a format wherein each memory address location stores at least a pair of said four-bit characters, comprising: means for reading said memory and providing a sequence of said characters in which each individual character of said sequence is a selected one of of a first character set, a second character set and a unique shift indicating character that separates characters from different sets to indicate that a change of character set has occurred in said sequence; first and second code tables; and means for alternately selecting said first and second code tables in response to each occurrence of said shift indicating character in said sequence for decoding all characters of said first set in accordance with said first code table for decoding all characters of said second set in accordance with said second code table to provide a sequence of decoded output characters.
Claim 7
Dependent Claim
153 words
Apparatus for decompacting four-bit characters stored in a memory in a format wherein each memory address location stores at least a pair of said four-bit characters, comprising: means for reading said memory and providing a sequence of said characters in which each individual character of said sequence is a selected one of of a first character set, a second character set and a unique shift indicating character that separates characters from different sets to indicate that a change of character set has occurred in said sequence; first and second code tables; and means for alternately selecting said first and second code tables in response to each occurrence of said shift indicating character in said sequence for decoding all characters of said first set in accordance with said first code table for decoding all characters of said second set in accordance with said second code table to provide a sequence of decoded output characters.
Claim 8
Dependent Claim
20 words
Apparatus as recited in claim 5 wherein said apparatus comprises a micro-computer having a read-only-memory organized as 8-bits per byte.
Claim 9
Dependent Claim
16 words
Apparatus as recited in claim 5 wherein said memory is organized in multiples of 4 bits.
Claim 10
Dependent Claim
18 words
Apparatus as recited in claim 5 wherein said memory is organized to provide 8-bits per byte of storage.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-10-19 | 1991-04-20 | 1991-10-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-10-19 | 1995-04-20 | 1995-10-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-10-19 | 1999-04-20 | 1999-10-20 | $7700.00 | Window Closed / Lapsed |