Patent US4032756A successfully refreshed from Google Patents.
US4032756A
Expired / Lapsed
US
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Tacan-dme identity detector
Assignee: International Telephone and Telegraph Corp
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Filing: 1975-08-14
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Granted: 1977-06-28
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Expires: 1995-08-14
Abstract
Abstract This relates to a method and apparatus for extracting identity information from a Tacan signal which occurs during a 5 second interval every 37.5 seconds. The identity information consists of marks and spaces wherein a mark comprises a predetermined number of adjacent group reference signals, each having therebetween a plurality of regularly spaced Tacan pulse pairs. The Tacan signal is sampled at regular intervals following each group reference signals by means of a gating arrangement. A first counter counts the number of coincidences between pulse pairs and gates generated by the gating arrangement. A second counter counts the total number of gates generated and when the ratio of the number of coincidences to the total number of gates reaches a preset threshold, a mark counter is incremented. When the ratio of the contents of the mark counter to the total number of group reference signals reaches a preset value, a mark is declared. If a preset number of intervals between group reference signals occur which do not meet the requirements of a mark, a space is declared.
Inventors
- 👤 Maurice Leon Jean Jezo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 14:09
CPC Classifications
G; G01; G01S; G01S1/00; G01S1/02; G01S1/08; G01S1/44
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
229 words
An apparatus for extracting identity information from a Tacan signal wherein said identity information consists of marks and spaces and wherein said Tacan signal includes group reference signals, said marks comprising a predetermined number of adjacent group reference signals having therebetween a plurality of regularly spaced Tacan pulse pairs comprising: means for sampling said Tacan signal at predetermined sample intervals after each of said group reference signals, said means for sampling comprising: first means for receiving said group reference signals; second means for receiving said pulse pairs; trigger means coupled to said first and second receiving means for generating trigger signals in response to said group reference signals and pulse pairs; and means responsive to said trigger signals for generating a plurality of regularly spaced gating signals; means for indicating a hit when one of said regularly spaced pulse pairs is present during said sample interval; a mark counter; means for incrementing said mark counter when the ratio of hits to sample intervals between adjacent group reference signals equals a preselected value; and means for declaring a mark when the ratio of the contents of said mark counter to the total number of group reference signals equals a preselected value and for declaring a space when the ratio of the contents of said mark counter to the total number of group reference signals is less than said preselected value.
Claim 2
Independent Claim
229 words
An apparatus for extracting identity information from a Tacan signal wherein said identity information consists of marks and spaces and wherein said Tacan signal includes group reference signals, said marks comprising a predetermined number of adjacent group reference signals having therebetween a plurality of regularly spaced Tacan pulse pairs comprising: means for sampling said Tacan signal at predetermined sample intervals after each of said group reference signals, said means for sampling comprising: first means for receiving said group reference signals; second means for receiving said pulse pairs; trigger means coupled to said first and second receiving means for generating trigger signals in response to said group reference signals and pulse pairs; and means responsive to said trigger signals for generating a plurality of regularly spaced gating signals; means for indicating a hit when one of said regularly spaced pulse pairs is present during said sample interval; a mark counter; means for incrementing said mark counter when the ratio of hits to sample intervals between adjacent group reference signals equals a preselected value; and means for declaring a mark when the ratio of the contents of said mark counter to the total number of group reference signals equals a preselected value and for declaring a space when the ratio of the contents of said mark counter to the total number of group reference signals is less than said preselected value.
Claim 3
Dependent Claim
29 words
An apparatus according to claim 1 wherein said indicating means comprises means for generating a hit signal each time a pulse pair coincides with one of said gating signals.
Claim 4
Dependent Claim
128 words
An apparatus according to claim 2 wherein said incrementing means comprises: a first counter coupled to said indicating means, which first counter is incremented each time a hit is indicated; a second counter coupled to said trigger means, which second counter is incremented each time a trigger signal is generated; first means for comparing the contents of said first counter with a predetermined value and generating a first output signal when an affirmative comparison is made, said first output signal incrementing said mark counter; second means for comparing the contents of said second counter with a predetermined value and generating a second output when an affirmative comparison is made; and means responsive to the first of said first and second outputs for resetting said first and second counters.
Claim 5
Dependent Claim
98 words
An apparatus according to claim 3 wherein said declaring means comprises: a third counter for counting the total number of group reference signals; means for comparing the contents of said mark counter with a predetermined value and generating a third output indicating a mark when an affirmative comparison is made; means for comparing the contents of said third counter with a predetermined value and generating a fourth output indicating a space when an affirmative comparison is made; and means responsive to the first of said third and fourth outputs for resetting said mark counter and said third counter.
Claim 6
Dependent Claim
17 words
An apparatus according to claim 4 further including means for indicating the conclusion of said identity information.
Claim 7
Dependent Claim
59 words
An apparatus according to claim 5 wherein said means for indicating the conclusion of said identity information comprises: a fourth counter for counting successive spaces; means for comparing the contents of said fourth counter with a predetermined value and generating a fifth output when an affirmative comparison is made, said fourth counter being reset when a mark is declared.
Claim 8
Dependent Claim
37 words
An apparatus according to claim 6 wherein said identity information occurs at specified time intervals and further including means for enabling said sampling means during said specified intervals and inhibiting said sampling means at all other times.
Claim 9
Dependent Claim
98 words
An apparatus according to claim 1 wherein said declaring means comprises: a third counter for counting the total number of group reference signals; means for comparing the contents of said mark counter with a predetermined value and generating a third output indicating a mark when an affirmative comparison is made; means for comparing the contents of said third counter with a predetermined value and generating a fourth output indicating a space when an affirmative comparison is made; and means responsive to the first of said third and fourth outputs for resetting said mark counter and said third counter.
Claim 10
Dependent Claim
17 words
An apparatus according to claim 1 further including means for indicating the conclusion of said identity information.
Claim 11
Dependent Claim
59 words
An apparatus according to claim 9 wherein said means for indicating the conclusion of said identity information comprises: a fourth counter for counting successive spaces; means for comparing the contents of said fourth counter with a predetermined value and generating a fifth output when an affirmative comparison is made, said fourth counter being reset when a mark is declared.
Claim 12
Dependent Claim
37 words
An apparatus according to claim 1 wherein said identity information occurs at specified time intervals and further including means for enabling said sampling means during said specified intervals and inhibiting said sampling means at all other times.
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) | 1980-06-27 | 1980-12-27 | 1981-06-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-06-27 | 1984-12-27 | 1985-06-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-06-27 | 1988-12-27 | 1989-06-28 | $7700.00 | Window Closed / Lapsed |