US3794995A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Modulation signal generator and apparatus using such generator
Assignee: Raytheon Co
•
Filing: 1972-08-02
•
Granted: 1974-02-26
•
Expires: 1992-08-02
Abstract
Abstract Improved apparatus for generating a time-varying analog signal, as for example, a chirp modulation signal for a pulse compression radar, is shown. The disclosed apparatus incorporates: a memory for storing a set of digital words representative of samples of the time-varying analog signal; at least two digital-to-analog converters having their outputs connected to a common bus; and means for distributing, at a predetermined rate, successively read digital words from the memory to the digital-to-analog converters. Each one of the latter elements is actuated also by a time-varying weighting signal so the frequency spectrum of the desired time-varying analog signal is within predetermined limits.
Inventors
- 👤 B Thompson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 03:59
CPC Classifications
G; G01; G01S; G01S13/00; G01S13/02; G01S13/06; G01S13/08; G01S13/10; G01S13/26; G01S13/28; G01S13/282; H; H03; H03C; H03C1/00
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
149 words
In a pulse radar system periodically transmitting a coded modulation signal, such modulation signal being generated by conversion of a set of digital words stored in a memory, improved conversion apparatus comprising: a. means for periodically reading the set of digital words out of the memory at a first rate and dividing such set into equal interlaced subsets of digital words; b. a number, corresponding to the number of subsets of digital words, of digital-to-analog converters, each one thereof being responsive to a different one of the equal interleaved sets of digital words to produce a different analog signal at a second rate lower than the first rate; c. weighting means for applying a different time-varying signal at the second rate to each one of the diGital-to-analog converters to weight each different analog signal; and d. means for combining each different analog signal to produce the coded modulation signal.
Claim 2
Dependent Claim
149 words
In a pulse radar system periodically transmitting a coded modulation signal, such modulation signal being generated by conversion of a set of digital words stored in a memory, improved conversion apparatus comprising: a. means for periodically reading the set of digital words out of the memory at a first rate and dividing such set into equal interlaced subsets of digital words; b. a number, corresponding to the number of subsets of digital words, of digital-to-analog converters, each one thereof being responsive to a different one of the equal interleaved sets of digital words to produce a different analog signal at a second rate lower than the first rate; c. weighting means for applying a different time-varying signal at the second rate to each one of the diGital-to-analog converters to weight each different analog signal; and d. means for combining each different analog signal to produce the coded modulation signal.
Claim 3
Dependent Claim
77 words
Improved conversion apparatus as in claim 1 wherein the first-named means includes: a. a clock pulse generator producing clock pulses at a first rate; and, b. means for periodically dividing the clock pulses into a number, corresponding to the number of digital-to-analog converters, of equal interlaced subsets of clock pulses and applying such subsets of clock pulses to the memory to actuate each one of the digital-to-analog converters at a second rate, lower than the first rate.
Claim 4
Dependent Claim
76 words
Improved conversion apparatus as in claim 2 wherein the weighting means includes: a. a source of DC voltage; b. a number of oscillator means corresponding in number to the number of D/A converters, each one of such means being synchronized by a different one of the equal interlaced subsets of clock pulses, for producing cosinusoidal signals having different relative phases; and c. summing means to combine the DC voltage and each one of the cosinusoidal signals.
References Cited (Backward Citations)
US3019426A
Cited
US2993202A
Cited
US3345505A
Cited
US3328792A
Cited
US3475749A
Cited
US3422435A
Cited
US3639695A
Cited
US3646549A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-02-25 | 1977-08-27 | 1978-02-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-02-25 | 1981-08-27 | 1982-02-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-02-25 | 1985-08-27 | 1986-02-26 | $7700.00 | Window Closed / Lapsed |