US4095225A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Range side lobe suppression method for a phase modulated radar pulse
Assignee: Telefonaktiebolaget LM Ericsson AB
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Filing: 1976-11-22
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Granted: 1978-06-13
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Expires: 1996-11-22
Abstract
Abstract The present invention relates to a method for eliminating range side lobes of a phase modulated radar pulse when compressing the same in the receiver of a radar equipment. The incoming radar pulse is inverse filtered in the receiver by means of two digital filters. After filtering in the first filter the sequence thus obtained is reversed in time and the reversed sequence is again filtered in the second filter so that it is possible to use only stable filters for the inverse filtering.
Inventors
- 👤 Erik Osten Erikmats
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 09:09
CPC Classifications
G; G01; G01S; G01S13/00; G01S13/02; G01S13/06; G01S13/08; G01S13/10; G01S13/26; G01S13/28; G01S13/284; G01S13/288; H; H03; H03H; H03H17/00
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
187 words
In a radar equipment, a method for eliminating unwanted range side lobes in a received radar pulse when compressing the pulse, said pulse when transmitted being coded according to a certain code pattern and when received being converted to a sequence of digital values, said method comprising the steps of: filtering the sequence of digital values in a first digital filter whose digital transfer function has a number of poles with positions in the complex z-plane all corresponding to the positions of the zeros of the z-transform defining the certain code pattern situated within the unity circle |z| = 1 whereby a first digital sequence is obtained; reversing said first digital sequence to obtain a second digital sequence in which the digital values appear in reverse order relative to the digital values in said first digital sequence; and filtering said second digital sequence in a second digital filter whose digital transfer function has a number of poles with positions in the complex z-plane corresponding to the positions of the inverted values of the zeros outside the unity circle |z|= 1 of the z-transform of said code pattern.
Claim 2
Dependent Claim
187 words
In a radar equipment, a method for eliminating unwanted range side lobes in a received radar pulse when compressing the pulse, said pulse when transmitted being coded according to a certain code pattern and when received being converted to a sequence of digital values, said method comprising the steps of: filtering the sequence of digital values in a first digital filter whose digital transfer function has a number of poles with positions in the complex z-plane all corresponding to the positions of the zeros of the z-transform defining the certain code pattern situated within the unity circle |z| = 1 whereby a first digital sequence is obtained; reversing said first digital sequence to obtain a second digital sequence in which the digital values appear in reverse order relative to the digital values in said first digital sequence; and filtering said second digital sequence in a second digital filter whose digital transfer function has a number of poles with positions in the complex z-plane corresponding to the positions of the inverted values of the zeros outside the unity circle |z|= 1 of the z-transform of said code pattern.
Claim 3
Dependent Claim
18 words
Method as claimed in claim 1, wherein the sequence obtained from said second digital filter, is time reversed.
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) | 1981-06-12 | 1981-12-12 | 1982-06-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-06-12 | 1985-12-12 | 1986-06-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-06-12 | 1989-12-12 | 1990-06-13 | $7700.00 | Window Closed / Lapsed |