US3852746A
Expired / Lapsed
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Pulse compression radar
Assignee: Raytheon Co
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Filing: 1972-11-14
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Granted: 1974-12-03
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Expires: 1992-11-14
Abstract
Abstract An improved digital technique for generating a chirp modulation signal for a pulse compression radar is shown. A stored set of digital numbers having a minimum number of different absolute values of successive samples of the desired modulation signal is processed through a logic circuit to derive a second set of complex digital numbers describing such modulation signal; such second set is then converted to an analog signal which is taken as the chirp modulation signal.
Inventors
- 👤 O Lowenschuss
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 01:02
CPC Classifications
G; G01; G01S; G01S13/00; G01S13/02; G01S13/06; G01S13/08; G01S13/10; G01S13/26; G01S13/28; G01S13/282
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
190 words
A modulation signal generator in the transmitter of a pulse compression radar, such generator being responsive to a set of N clock pulses at the Nyquist rate, where ''''N'''' equals 3.2x and ''''x'''' is a positive integer greater than ''''1,'''' to produce a set of ''''N'''' complex digital numbers descriptive of a desired modulation signal and comprising: a. a read only memory having stored therein a set of digital members representing the possible absolute values of the in phase and quadrature components of the complex digital numbers to be produced; b. selection means, responsive to each successive one of a set of ''''N'''' clock pulses, for selecting ''''N'''' pairs of digital numbers in the read only memory corresponding to the absolute values of the in phase and quadrature components of successive ones of the complex digital numbers to be produced and for generating a digital representation of the sign of each one of such components; and c. a pair of digital multipliers for combining the selected in phase and quadrature components with a digital representation of sign to produce, at the Nyquist rate, the set of ''''N'''' complex digital numbers.
Claim 2
Dependent Claim
190 words
A modulation signal generator in the transmitter of a pulse compression radar, such generator being responsive to a set of N clock pulses at the Nyquist rate, where ''''N'''' equals 3.2x and ''''x'''' is a positive integer greater than ''''1,'''' to produce a set of ''''N'''' complex digital numbers descriptive of a desired modulation signal and comprising: a. a read only memory having stored therein a set of digital members representing the possible absolute values of the in phase and quadrature components of the complex digital numbers to be produced; b. selection means, responsive to each successive one of a set of ''''N'''' clock pulses, for selecting ''''N'''' pairs of digital numbers in the read only memory corresponding to the absolute values of the in phase and quadrature components of successive ones of the complex digital numbers to be produced and for generating a digital representation of the sign of each one of such components; and c. a pair of digital multipliers for combining the selected in phase and quadrature components with a digital representation of sign to produce, at the Nyquist rate, the set of ''''N'''' complex digital numbers.
Claim 3
Dependent Claim
121 words
A modulation signal generator as in claim 1 wherein the selection means includes: a. a counter, responsive to successive clock pulses, for producing a different count signal for each successive clock pulse; b. addressing means, responsive to each different count signal, for addressing the read only memory to derive the absolute values of the in phase and quadrature components of successive ones of the complex digital numbers to be produced; and, c. logic means, responsive to the addressing means, for selecting a digital representation of -1 for every odd clock pulse and a digital representation of +1 for every even clock pulse and for reversing the addressed in phase and quadrature components to the digital multipliers after every N/2 clock pulse.
Claim 4
Dependent Claim
76 words
A modulation signal generator as in claim 2 wherein the addressing means includes: a. means for squaring each different count signal out of the counter; b. a modulo-N divider, responsive to each squared count signal, for producing a remainder varying between a 0 and N for each count signal to actuate the logic means; c. a modulo-N/2 divider, responsive to the remainder out of the modulo-N divider, for producing an address for the read only memory.
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) | 1977-12-02 | 1978-06-03 | 1978-12-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-12-02 | 1982-06-03 | 1982-12-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-12-02 | 1986-06-03 | 1986-12-03 | $7700.00 | Window Closed / Lapsed |