US3706992A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Constant-duty transponder
Assignee: International Standard Electric Corp
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Filing: 1970-07-23
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Granted: 1972-12-19
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Expires: 1990-07-23
Abstract
Abstract This invention relates to a high efficiency transponder of the type which receives and decodes interrogation pulse pairs and transmits reply pulse pairs. Filler pulses (squitter) are transmitted to achieve a constant duty operation. Squitter is initiated by a local noise pulse generator, not be receiver noise. Therefor, the countdown due to dead-time following decoding of the squitter is eliminated and recognition of genuine interrogations is not inhibited.
Inventors
- 👤 Jacques Daniel Philippe Brisse
- 👤 Jean-Claude Joguet
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 01:28
CPC Classifications
G; G01; G01S; G01S13/00; G01S13/74; G01S13/76; G01S13/78; G01S13/785; G01S13/787
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
176 words
A transponder for transmitting a coded, spaced response pulse pair whenever coded interrogation pulse pair having predetermined spacing is received and recognized, comprising: means including an antenna and receiver for receiving said interrogation pulse pairs; a decoder responsive to the output of said receiver for recognizing said coded interrogation pulse pair and for generating an output signal representative of said recognition; response pulse pair encoding and transmitting means; delay means responsive to and in series with said decoder output for introducing a predetermined system delay between said recognition and transmission of said response pulse pair; a random distribution noise pulse generator and control means for generating a predetermined maximum number of randomly distributed noise pulses per unit of time, said random pulses being applied to said encoding and transmitting means for transmitting pulse pairs from said transponder substantially independently of said decoder output signal; and first inhibiting means responsive to said decoder output signal for preventing said randomly distributed pulses from reaching said encoding and transmitting means during a predetermined dead time after each transmitted response.
Claim 2
Dependent Claim
176 words
A transponder for transmitting a coded, spaced response pulse pair whenever coded interrogation pulse pair having predetermined spacing is received and recognized, comprising: means including an antenna and receiver for receiving said interrogation pulse pairs; a decoder responsive to the output of said receiver for recognizing said coded interrogation pulse pair and for generating an output signal representative of said recognition; response pulse pair encoding and transmitting means; delay means responsive to and in series with said decoder output for introducing a predetermined system delay between said recognition and transmission of said response pulse pair; a random distribution noise pulse generator and control means for generating a predetermined maximum number of randomly distributed noise pulses per unit of time, said random pulses being applied to said encoding and transmitting means for transmitting pulse pairs from said transponder substantially independently of said decoder output signal; and first inhibiting means responsive to said decoder output signal for preventing said randomly distributed pulses from reaching said encoding and transmitting means during a predetermined dead time after each transmitted response.
Claim 3
Dependent Claim
92 words
Apparatus according to claim 1 including second inhibiting means associated with said decoder for inhibiting the generation of said decoder output signals for a period at least equal to said predetermined dead time after each of said decoder output signals corresponding to an interrogation recognition, and said first inhibiting means are defined as being responsive to both said delay means output and said random pulses to inhibit said encoding and transmitting means after each transmission, whether said transmission was initiated by said recognized interrogations or by any of said random noise pulses.
Claim 4
Dependent Claim
56 words
Apparatus according to claim 2 in which said control means associated with said noise pulse generator is responsive to the signals at the input of said encoding means, whereby the number of noise pulses generated is controlled so that the sum of said noise pulses and decoder output pulses does not exceed said maximum predetermined number.
Claim 5
Dependent Claim
33 words
Apparatus according to claim 3 including means responsive to said encoder input for inhibiting the operation of said receiver for a second predetermined time following each interrogation recognition output signal from said decoder.
Claim 6
Dependent Claim
37 words
Apparatus according to claim 4 in which said second predetermined time is at least equal to the time separation between the pulses of a response pair plus the durations of the two pulses of said response pair.
Claim 7
Dependent Claim
30 words
Apparatus according to claim 4 in which said second predetermined time is substantially equal to twice the transmitted pulse width plus the spacing between pulses of said response pulse pair.
Claim 8
Dependent Claim
41 words
Apparatus according to claim 1 in which said delay means and said response pulse pair coder comprises a first shift register having a total overall delay of said predetermined system delay plus the time between pulses of said response pulse pair.
Claim 9
Dependent Claim
62 words
Apparatus according to claim 7 in which said random distribution noise pulse generator includes a second shift register having a total delay equal to said time between pulses of said response pulse pair, said shift register being connected to generate the second pulse of said response pair from the first pulse of said pair at the input of said second shift register.
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) | 1975-12-19 | 1976-06-19 | 1976-12-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-12-19 | 1980-06-19 | 1980-12-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-12-19 | 1984-06-19 | 1984-12-19 | $7700.00 | Window Closed / Lapsed |