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US3805234A
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Digital data transmission system
Assignee: Westinghouse Electric Corp
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Filing: 1972-07-31
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Granted: 1974-04-16
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Expires: 1992-07-31
Abstract
Abstract Apparatus for transmitting digital data and for correcting errors which occur in the transmission of the data while maintaining high transmission efficiency is disclosed. Digital data words are sequentially transmitted with each of the data words containing a field code related to the sequence in which the data words are extracted from the data source. A receiver detects and retransmits each of the digital data words including the field codes. The retransmitted data words are detected by the transmitter and compared to the words as originally transmitted. If an error is detected, the transmission sequence is repeated beginning with the word found to contain an error. This unique arrangement of the field codes permits the receiver to determine which words have been verified as correct by the transmitter. Transmission is not interrupted. Supervisory signals are not exchanged between transmitter and receiver.
Inventors
- 👤 H Masters
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 03:47
CPC Classifications
H; H04; H04L; H04L1/00; H04L1/12; H04L1/14
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
151 words
A digital data communication system comprising in combination: a. transmitting means for sequentially transmitting digital data words, each of said data words including a field code related to the sequence in which said data words were inputted by a data source to said transmitting means; b. receiving means including a memory for temporarily storing a selected number Of said data words and apparatus for restransmitting said temporarily stored data words to said transmitting means; c. compare means for comparing each said transmitted digital data words with its corresponding retransmitted data word and for generating an error signal when a difference is detected; d. means for inserting in the continuous data stream any data word which said error signal indicates was incorrectly transmitted; and e. output means for outputting one of said temporarily stored data words when the sequence of subsequent field codes indicates that the word to be outputted is correct.
Claim 2
Dependent Claim
151 words
A digital data communication system comprising in combination: a. transmitting means for sequentially transmitting digital data words, each of said data words including a field code related to the sequence in which said data words were inputted by a data source to said transmitting means; b. receiving means including a memory for temporarily storing a selected number Of said data words and apparatus for restransmitting said temporarily stored data words to said transmitting means; c. compare means for comparing each said transmitted digital data words with its corresponding retransmitted data word and for generating an error signal when a difference is detected; d. means for inserting in the continuous data stream any data word which said error signal indicates was incorrectly transmitted; and e. output means for outputting one of said temporarily stored data words when the sequence of subsequent field codes indicates that the word to be outputted is correct.
Claim 3
Dependent Claim
28 words
The digital communication system in accordance with claim 1 wherein all error detection is based on a bit comparison of the retransmitted data word to its stored counterpart.
Claim 4
Dependent Claim
34 words
The apparatus of claim 1 wherein said field codes are selected such that there is a low probability of one valid code being changed into a second valid code due to errors in transmission.
Claim 5
Dependent Claim
31 words
The digital communication system in accordance with claim 1 wherein said data word includes a non-data portion comprising a start bit, a stop bit and the bits of said field code.
Claim 6
Dependent Claim
56 words
The digital system in accordance with claim 4 wherein the number of said non-data bits is independent of the number of data bits contained in each of said data words thereby providing a system wherein the ratio of data to non-data bits increases as the number of data bits in each of said data words increases.
Claim 7
Dependent Claim
42 words
A digital communication system in accordance with claim 1 wherein: 9 said transmission means assigns in sequential order one of four field codes and any data word retransmitted because of an error introduced in the transmission process retains its original field code.
Claim 8
Dependent Claim
43 words
A digital communication system in accordance with claim 1 wherein the transmitting station determines which words have been verified as transmitted error free and the data words stored at the receiver are outputted in the same sequence they were entered into the transmitter.
Claim 9
Dependent Claim
20 words
The digital communication system in accordance with claim 1 including apparatus for retransmitting two words when an error is detected.
Claim 10
Independent Claim
167 words
A method of accurately transferring a data message between remote locations, the method comprising the steps of: a. combining each of the digital information words comprising the message to be transmitted with a field code to form digital words; b. temporary storing in a first memory and in the absence of error sequentially transmitting said digital data words in a continuous data stream via first transmission means to a receiver where said data words are temporarily stored in a second memory; c. returning said digital data words via a second transmission means to compare means located at the point of origin of said data words where each of said retransmitted data words are compared with the corresponding transmitted word; d. reinserting into the continuous data stream any data word, which is found to differ from the word as transmitted; and e. outputting said temporarily stored data words in a sequence determined by examining the field codes of subsequently arriving data words to form an output data signal.
Claim 11
Independent Claim
167 words
A method of accurately transferring a data message between remote locations, the method comprising the steps of: a. combining each of the digital information words comprising the message to be transmitted with a field code to form digital words; b. temporary storing in a first memory and in the absence of error sequentially transmitting said digital data words in a continuous data stream via first transmission means to a receiver where said data words are temporarily stored in a second memory; c. returning said digital data words via a second transmission means to compare means located at the point of origin of said data words where each of said retransmitted data words are compared with the corresponding transmitted word; d. reinserting into the continuous data stream any data word, which is found to differ from the word as transmitted; and e. outputting said temporarily stored data words in a sequence determined by examining the field codes of subsequently arriving data words to form an output data signal.
Claim 12
Dependent Claim
22 words
The method of transmitting digital data in accordance with claim 9 wherein the number of data words comprising a message is variable.
Claim 13
Independent Claim
99 words
A system for accurately transmitting digital data words between remote locations, comprising in combination: a. means located at the point where the data originates for transmitting data in a continuous stream to the point of destination; b. means located at the point of destination for returning said data to the point of origin; c. means located at said point of origin for comparing each of the returned data to the previously transmitted counterpart and generating an error signal when a difference is found; d. means for reinserting into said continuous data stream any data word found to contain errors.
Claim 14
Independent Claim
99 words
A system for accurately transmitting digital data words between remote locations, comprising in combination: a. means located at the point where the data originates for transmitting data in a continuous stream to the point of destination; b. means located at the point of destination for returning said data to the point of origin; c. means located at said point of origin for comparing each of the returned data to the previously transmitted counterpart and generating an error signal when a difference is found; d. means for reinserting into said continuous data stream any data word found to contain errors.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-04-15 | 1977-10-15 | 1978-04-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-04-15 | 1981-10-15 | 1982-04-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-04-15 | 1985-10-15 | 1986-04-16 | $7700.00 | Window Closed / Lapsed |