US4074263A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Code signal processing circuitry for iff transponder beacon
Assignee: United States Department of the Army
•
Filing: 1969-01-27
•
Granted: 1978-02-14
•
Expires: 1989-01-27
Abstract
Abstract The circuit includes means for regenerating and removing noise from a reced pseudo-random IFF interrogation signal modulated onto a radar signal. The regenerated code is decoded by correlating it with a locally generated replica thereof which is run at a different bit rate, thus achieving asynchronous correlation.
Inventors
- 👤 Albert M. Sullivan, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 06:18
CPC Classifications
G; G01; G01S; G01S13/00; G01S13/74; G01S13/79
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
114 words
Transponder beacon circuitry for processing received binary coded signals, comprising a received radar video pulse train which is time modulated in accordance with a binary code, means to extract the binary code from said pulse train in two-level form, said means including a resonant filter tuned to the pulse repetition frequency of said radar video pulse train and a pulse shaper in cascade therewith and wherein said resonant filter is shock excited by said received video pulse train, whereby said pulse shaper produces an unmodulated video pulse train, and means for correlating said extracted binary code with a locally stored code which is run at a different bit rate than said extracted binary code.
Claim 2
Dependent Claim
114 words
Transponder beacon circuitry for processing received binary coded signals, comprising a received radar video pulse train which is time modulated in accordance with a binary code, means to extract the binary code from said pulse train in two-level form, said means including a resonant filter tuned to the pulse repetition frequency of said radar video pulse train and a pulse shaper in cascade therewith and wherein said resonant filter is shock excited by said received video pulse train, whereby said pulse shaper produces an unmodulated video pulse train, and means for correlating said extracted binary code with a locally stored code which is run at a different bit rate than said extracted binary code.
Claim 3
Dependent Claim
76 words
The circuitry of claim 1 wherein said last-named means comprises an Exclusive-OR gate and a stored code generator, the inputs of said gate being said extracted binary code and the output of said stored code generator, an inverter and a low pass filter connected in cascade to the output of said gate, and a threshold circuit comprising a Schmitt trigger connected to said low pass filter, said Schmitt trigger being arranged to actuate reply control circuits.
Claim 4
Dependent Claim
97 words
Decoding circuitry for an IFF transponder beacon, comprising, a received interrogating signal comprising a pseudo-random code, means to correlate said received signal in an asynchronous manner with a locally stored replica of said received signal by operating said locally stored replica at a different bit rate than said received signal, and wherein said means comprises an Exclusive - or gate, an inverter and a low pass filter all connected in cascade in the order named, and a stored code generator, the inputs of said gate being said received signal and the output of said stored code generator.
Claim 5
Dependent Claim
97 words
Decoding circuitry for an IFF transponder beacon, comprising, a received interrogating signal comprising a pseudo-random code, means to correlate said received signal in an asynchronous manner with a locally stored replica of said received signal by operating said locally stored replica at a different bit rate than said received signal, and wherein said means comprises an Exclusive - or gate, an inverter and a low pass filter all connected in cascade in the order named, and a stored code generator, the inputs of said gate being said received signal and the output of said stored code generator.
Claim 6
Dependent Claim
42 words
The circuitry of claim 3 further including a threshold device connected to the output of said low pass filter, said device being arranged to actuate a reply circuit when the threshold thereof is exceeded by the output of said low pass filter.
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) | 1981-02-13 | 1981-08-15 | 1982-02-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-02-13 | 1985-08-15 | 1986-02-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-02-13 | 1989-08-15 | 1990-02-14 | $7700.00 | Window Closed / Lapsed |