US3889064A
Expired / Lapsed
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Asynchronous, multiplexing, single line transmission and recovery data system
Assignee: National Aeronautics and Space Administration
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Filing: 1974-03-27
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Granted: 1975-06-10
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Expires: 1994-03-27
Abstract
Abstract Asynchronously multiplexed sample data sub-systems employ transmission over a single line to a remote synchronizer and demultiplexer. At the remote synchronizer, the data is recovered by synchronizing signals derived from the data itself. A sub-system, or satellite location, supplies continuously sampled binary data along with a satellite identification and synchronizing sequence as a satellite message frame. This information is supplied bit-serially, to a multiplexer junction. The multiplexed satellite information is delivered asynchronously onto a single line transmission channel with other like bit serial satellite message information from other satellite monitoring sites. Such satellite information is transmitted to a central collection and analysis site where it is demultiplexed according to the words and bits that make up a satellite message frame. At least two message frames from each satellite monitoring site are always placed on the single transmission channel as a single block of data for that satellite. This technique, at the demultiplexer, assures proper recognition of a desired message frame based upon a comparison of satellite identification sequences and a frame synchronization sequence.
Inventors
- 👤 James C Administrator Fletcher
- 👤 Tage O Anderson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 18:51
CPC Classifications
H; H04; H04B; H04B7/00; H04B7/14; H04B7/15; H04B7/204; H04B7/212; H04B7/2125; H04J; H04J3/00; H04J3/24
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
115 words
A unidirectional, single channel communication system for transmitting binary data from a plurality of satellite data sampling sites to a central location, comprising: means at each of said satellite data sampling sites for forming of a pair of satellite message frames each having a binary synchronizing sequence, a satellite identification sequence and data words; means responsive to received satellite message frames from said plurality of sampling sites for asynchronously multiplexing a pair of frames from each satellite location onto a single transmission channel; and satellite message receiving means at said central location for synchronizing and demultiplexing a frame in accordance with the satellite identification sequence, the binary synchronizing sequence and the data words per frame.
Claim 2
Dependent Claim
115 words
A unidirectional, single channel communication system for transmitting binary data from a plurality of satellite data sampling sites to a central location, comprising: means at each of said satellite data sampling sites for forming of a pair of satellite message frames each having a binary synchronizing sequence, a satellite identification sequence and data words; means responsive to received satellite message frames from said plurality of sampling sites for asynchronously multiplexing a pair of frames from each satellite location onto a single transmission channel; and satellite message receiving means at said central location for synchronizing and demultiplexing a frame in accordance with the satellite identification sequence, the binary synchronizing sequence and the data words per frame.
Claim 3
Dependent Claim
101 words
The unidirectional, single channel communication system of claim 1 wherein said satellite message frame forming means comprises: an N bit long register for receiving N bits of sampled data; an X bit long register for receiving Y bits of satellite identification sequence and X-Y bits of satellite message frame synchronizing sequence; means for serially transferring said X bits from said X bit long register to said multiplexing means; and means operative immediately after said X bits have been transferred for transferring N bits from said N bit long register to said multiplexing means until M X N bits have been transferred.
Claim 4
Dependent Claim
60 words
The unidirectional, single channel communication system of claim 2 wherein said X bit serial transferring means, comprises: a source of clocking signals; a modulo X bit counter driven by said source of clocking signals; and logic circuit means responsive to the output of said modulo X bit counter for disabling application of the clocking signals to said modulo X counter.
Claim 5
Dependent Claim
75 words
The unidirectional, single channel communication system of claim 2 wherein said N bit serial transferring means, comprises: a source of clocking signals; a modulo N bit counter driven by said source of clocking signals; a modulo M bit counter driven by the output of said modulo N bit counter; and logic circuit means responsive to the output of said modulo M bit counter for disabling application of the clocking signals to said modulo N counter.
Claim 6
Dependent Claim
48 words
The unidirectional, single channel communication system of claim 1 wherein said satellite message frame muLtiplexing means, comprises: a Z to 1 multiplexer circuit; a binary counter means addressing said Z to 1 multiplexer circuit; and a source of clocking signals connected to and driving said binary counter means.
Claim 7
Dependent Claim
45 words
The unidirectional, single channel communication system of claim 5 wherein said source of clocking signals has a signal frequency rate that permits at least a pair of satellite message frames to pass serially through said Z to 1 multiplexer circuit before another satellite is selected.
Claim 8
Dependent Claim
67 words
The unidirectional, single channel communication system of claim 1 wherein said demultiplexing means comprises: an X bit long register means for serially receiving the plurality of multiplexed satellite message frames; and a phase lock loop clocking the bits of the received message frames into said X bit long shift register, said serially received satellite message frames also being supplied to the input of said phase lock loop.
Claim 9
Dependent Claim
96 words
The unidirectional, single channel communication system of claim 7 wherein said demultiplexing means further comprises: means for continuously comparing X-Y bits of a standard synchronizing sequence with X-Y bits in said X bit long register means; a Y bit long satellite identification sequence register means for storing the previously received identification sequence; and means for comprising the Y bits of the identification sequence in said X bit long register means and the Y bits of the identification sequence in said Y bit long register means, whereby the start of a new satellite message frame is identified.
Claim 10
Dependent Claim
74 words
The unidirectional, single channel communication system of claim 8 further comprising: a modulo N bit counter means clocked by the clock output of said phase lock loop for transferring N bit long words from said X bits long shift register; and a modulo M bit counter means clocked by the output of said modulo N bit counter for inhibiting the further transfer of N bit long words from said X bit long register means.
Claim 11
Dependent Claim
87 words
The unidirectional, single channel communication system of claim 1 wherein said demultiplexing means comprises: means for continuously comparing the bits of a standard synchronizing sequence with the bits in received satellite message frames; and means for continuously comparing the bits of a previously received satellite identification sequence with the bits in a subsequently received satellite message frame; and logic means responsive to said satellite identification comparing means and said synchronizing sequence comparing means for emitting a signal indicative of the start of a new satellite message frame.
Claim 12
Dependent Claim
59 words
The unidirectional, single channel communication system of claim 10 and further comprising: means responsive to said synchronizing sequence comparison means for emitting a signal when the compared signals match; means responsive to said satellite identification sequence comparison means for emitting a signal when the compared signals do not match; and means applying said emitted signals to said logic means.
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) | 1978-06-09 | 1978-12-09 | 1979-06-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-06-09 | 1982-12-09 | 1983-06-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-06-09 | 1986-12-09 | 1987-06-10 | $7700.00 | Window Closed / Lapsed |