US3963869A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Parity framing of pulse systems
Assignee: AT&T Inc
•
Filing: 1974-12-02
•
Granted: 1976-06-15
•
Expires: 1994-12-02
Abstract
Abstract A carrier system is described in which a number of pulse encoded signals are multiplexed on a single transmission and demultiplexed and decoded at a remote terminal for distribution to a number of receivers at that location. A similar multiplex system uses a separate return pair of transmitting signals in the opposite direction. The multiplexed signals on each transmission line are framed by means of a framing pulse in each frame having a value which insures a preselected parity for each frame. To make sure that parity discrepancies will exist for other pulse positions even under all "1s" and all "0s" conditions, a second bit position is filled with a randomly-valued bit.
Inventors
- 👤 James Lewis Caldwell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 16:04
CPC Classifications
H; H04; H04J; H04J3/00; H04J3/02; H04J3/06; H04J3/0602; H04J3/0605; H04J3/0611; H04L; H04L7/00; H04L7/04; H04L7/048
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
84 words
A multiplex pulse transmission terminal comprising: means for interleaving a plurality of pulse streams into a single pulse stream, means for dividing said single pulse stream into successive frames of pulses including preselected sequences of pulses from said plurality of pulse streams, means for inserting a randomly-valued pulse derived independently of said pulse streams into each said frame of pulses, means for ascertaining the parity of each said frame of pulses, and means for inserting a parity pulse in each said frame of pulses.
Claim 2
Dependent Claim
84 words
A multiplex pulse transmission terminal comprising: means for interleaving a plurality of pulse streams into a single pulse stream, means for dividing said single pulse stream into successive frames of pulses including preselected sequences of pulses from said plurality of pulse streams, means for inserting a randomly-valued pulse derived independently of said pulse streams into each said frame of pulses, means for ascertaining the parity of each said frame of pulses, and means for inserting a parity pulse in each said frame of pulses.
Claim 3
Dependent Claim
95 words
A multiplex pulse receiving terminal comprising: means for receiving a single pulse stream including pulse positions dividing said single pulse stream into successive frames of pulses, means for ascertaining the parity of groups of successive pulses in said single pulse stream, each of said groups including one of said frames and the final pulse of the next previous frame, means for detecting a bit position providing a preselected parity over said group of successive pulses, and means, responsive to said detecting means, for separating said single pulse stream into a plurality of separate pulse streams.
Claim 4
Dependent Claim
95 words
A multiplex pulse receiving terminal comprising: means for receiving a single pulse stream including pulse positions dividing said single pulse stream into successive frames of pulses, means for ascertaining the parity of groups of successive pulses in said single pulse stream, each of said groups including one of said frames and the final pulse of the next previous frame, means for detecting a bit position providing a preselected parity over said group of successive pulses, and means, responsive to said detecting means, for separating said single pulse stream into a plurality of separate pulse streams.
Claim 5
Dependent Claim
64 words
A pulse framing circuit comprising: a source of a stream of information-bearing pulses having regularly recurring pulse position dependent properties, means for subdividing said stream into repetitive groups of pulse positions, means for inserting a randomly-valued pulse derived independently of said information-bearing pulses into each said group of pulse positions, and means for adding a parity bit to each said group of pulse positions.
Claim 6
Dependent Claim
64 words
A pulse framing circuit comprising: a source of a stream of information-bearing pulses having regularly recurring pulse position dependent properties, means for subdividing said stream into repetitive groups of pulse positions, means for inserting a randomly-valued pulse derived independently of said information-bearing pulses into each said group of pulse positions, and means for adding a parity bit to each said group of pulse positions.
Claim 7
Dependent Claim
21 words
The pulse framing circuit according to claim 3 wherein said pulse stream comprises frames of multiplexed pulses from different pulse sources.
Claim 8
Dependent Claim
42 words
The pulse framing circuit according to claim 3 wherein the value of said parity bit is determined by the parity bit of the previous group of pulse positions as well as by the group of pulse positions to whic it is added.
Claim 9
Dependent Claim
76 words
A frame detection circuit comprising a source of a stream of information-bearing pulses including pulse positions dividing said stream into successive frames of pulse positions, means for parity-checking groups of pulse positions of said stream, said groups each including one of said frames and at least one preceding pulse position, means, responsive to said parity-checking means, for framing said successive groups of pulse positions, and means, responsive to said framing means, for demultiplexing said pulse stream.
Claim 10
Dependent Claim
76 words
A frame detection circuit comprising a source of a stream of information-bearing pulses including pulse positions dividing said stream into successive frames of pulse positions, means for parity-checking groups of pulse positions of said stream, said groups each including one of said frames and at least one preceding pulse position, means, responsive to said parity-checking means, for framing said successive groups of pulse positions, and means, responsive to said framing means, for demultiplexing said pulse stream.
Claim 11
Dependent Claim
21 words
The frame detection circuit according to claim 6 wherein said pulse stream comprises frames of multiplexed pulses from different pulse sources.
Claim 12
Dependent Claim
47 words
The frame detection circuit according to claim 6 further comprising: a misframe detecting means, responsive to said parity-checking means, for detecting a preselected pattern of incorrectly framed groups of pulse positions, and means responsive to said misframe detecting means for reframing said groups of successive pulse positions.
Claim 13
Dependent Claim
35 words
The frame detection circuit according to claim 8 further comprising: an error detection circuit for detecting errors in said pulse stream, and means responsive to said error detecting circuit for disabling said misframe detection means.
Claim 14
Dependent Claim
45 words
A multiplex pulse transmission system comprising: means for adding parity bits to successive multiplex frames in said system, means for adding independently derived random bits to said successive multiplex frames in said system, and means, utilizing said parity bits, for detecting misframing in said system.
Claim 15
Dependent Claim
45 words
A multiplex pulse transmission system comprising: means for adding parity bits to successive multiplex frames in said system, means for adding independently derived random bits to said successive multiplex frames in said system, and means, utilizing said parity bits, for detecting misframing in said system.
Claim 16
Independent Claim
94 words
The method of maintaining correct framing of a multiplex pulse transmission system comprising the steps of: 1. inserting an independently derived randomly-valued pulse in each frame of pulse positions in said system; 2. inserting a framing pulse in each said frame having a value dependent on the parity of the preceding frame of pulse positions in said system; 3. detecting the parity of each frame of pulse positions in said system; and 4. determining the proper framing of said pulse positions by comparing said parity to pulse value in any prospective framing pulse position.
Claim 17
Independent Claim
94 words
The method of maintaining correct framing of a multiplex pulse transmission system comprising the steps of: 1. inserting an independently derived randomly-valued pulse in each frame of pulse positions in said system; 2. inserting a framing pulse in each said frame having a value dependent on the parity of the preceding frame of pulse positions in said system; 3. detecting the parity of each frame of pulse positions in said system; and 4. determining the proper framing of said pulse positions by comparing said parity to pulse value in any prospective framing pulse position.
Claim 18
Dependent Claim
40 words
The method of maintaining correct framing according to claim 11 further including the steps of: 5. detecting improperly framed groups of pulse positions; and 6. reframing said pulse positions in response to a plurality of misframed groups of pulse positions.
Claim 19
Dependent Claim
33 words
The method of maintaining correct framing according to claim 12 further including the steps of: 7. detecting transmission errors occurring in said system; and 8. inhibiting step (5) whenever a transmission error occurs.
References Cited (Backward Citations)
US3456239A
Cited
US3529089A
Cited
US3591720A
Cited
US3587043A
Cited
US3707604A
Cited
US3740478A
Cited
US3766316A
Cited
US3804982A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-06-15 | 1979-12-15 | 1980-06-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-06-15 | 1983-12-15 | 1984-06-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-06-15 | 1987-12-15 | 1988-06-15 | $7700.00 | Window Closed / Lapsed |