US4709237A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Device for eliminating low frequency noise from a transmission system, in particular 1/f noise in a homodyne radar receiver
Assignee: LMT Radio Professionnelle
•
Filing: 1985-12-03
•
Granted: 1987-11-24
•
Expires: 2005-12-03
Abstract
Abstract Device for eliminating the noise in 1/f from a Doppler radar comprising in the HF emitting system, a phase coder introducing, at frequency PRF/2 a phase shift of 0 and π alternately, and in the receiving system, after the receiver, a decoder, or gain inverter progrmmable between -1 and +1, acting, in the same manner as the coder, upon the receiving signal and comprising a low-pass filter downstream from the decoder for eliminating the noise in 1/f, that appears at PRF/2, the device being applied to a ground surveying radar.
Inventors
- 👤 Michel Poullain
- 👤 Alain Marcuard
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 02:16
CPC Classifications
G; G01; G01S; G01S13/00; G01S13/02; G01S13/06; G01S13/08; G01S13/10; G01S13/26; G01S7/00; G01S7/02; G01S7/28
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
133 words
Device for eliminating low frequency noise from a transmission system, in particular noise in l/f in a homodyne radar receiver the transmitted signal which is a frequency Fo carrier, modulated, chopped at a repetition frequency PRF by time-slots of width to, wherein said device comprises in the transmitting circuit a coder device acting, according to two complementary values, upon the transmitted signal, these two values being alternately introduced at a frequency at most equal to PRF/2 and in the receiving circuit a decoder acting in the same way as the coder device, upon the receiving signal, wherein the coder device and the decoder device each comprise a phase coder for phase shifting alternately by 0 and π, the transmitted and the received signal, respectively, and followed by a sample-and-hold device and a low-pass
Claim 2
Dependent Claim
133 words
Device for eliminating low frequency noise from a transmission system, in particular noise in l/f in a homodyne radar receiver the transmitted signal which is a frequency Fo carrier, modulated, chopped at a repetition frequency PRF by time-slots of width to, wherein said device comprises in the transmitting circuit a coder device acting, according to two complementary values, upon the transmitted signal, these two values being alternately introduced at a frequency at most equal to PRF/2 and in the receiving circuit a decoder acting in the same way as the coder device, upon the receiving signal, wherein the coder device and the decoder device each comprise a phase coder for phase shifting alternately by 0 and π, the transmitted and the received signal, respectively, and followed by a sample-and-hold device and a low-pass
Claim 3
Dependent Claim
36 words
Device according to claim 1, wherein the coder device is connected between a modulator circuit and a transmitting amplifier circuit, and the decoder device is connected at the output of the receiver of the receiving circuit.
Claim 4
Dependent Claim
44 words
Device according to claim 1, applied to a Doppler-type radar system, wherein the coder device is constituted by a PIN diode phase shift device and the decoder device is constituted by a video-frequency amplifier having a gain that is programmable between +1 and -1.
Claim 5
Dependent Claim
134 words
Device for eliminating low frequency noise from a transmission system, in particular noise in l/f in a homodyne radar receiver the transmitted signal which is a frequency Fo carrier, coded, chopped at a repetition frequency PRF by time-slots of width to, wherein said device comprises in the transmitting circuit a coder device acting, according to two complementary values, upon the transmitted signal, these two values being alternately introduced at a frequency at most equal to PRF/2 and in the receiving circuit a decoder acting in the same way as the coder device, upon the receiving signal, wherein the coder device and the decoder device each comprise a phase coder for phase shifting alternately by 0 and π, the transmitted and the received signal, respectively, and followed by a sample-and-hold device and a low-pass filter.
Claim 6
Dependent Claim
134 words
Device for eliminating low frequency noise from a transmission system, in particular noise in l/f in a homodyne radar receiver the transmitted signal which is a frequency Fo carrier, coded, chopped at a repetition frequency PRF by time-slots of width to, wherein said device comprises in the transmitting circuit a coder device acting, according to two complementary values, upon the transmitted signal, these two values being alternately introduced at a frequency at most equal to PRF/2 and in the receiving circuit a decoder acting in the same way as the coder device, upon the receiving signal, wherein the coder device and the decoder device each comprise a phase coder for phase shifting alternately by 0 and π, the transmitted and the received signal, respectively, and followed by a sample-and-hold device and a low-pass filter.
Claim 7
Dependent Claim
36 words
Device according to claim 4 wherein the coder device is connected between a modulator circuit and a transmitting amplifier circuit, and the decoder device is connected at the output of the receiver of the receiving circuit.
Claim 8
Dependent Claim
44 words
Device according to claim 4, applied to a Doppler-type radar system, wherein the coder device is constituted by a PIN diode phase shift device and the decoder device is constituted by a video-frequency amplifier having a gain that is programmable between +1 and -1.
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) | 1990-11-23 | 1991-05-25 | 1991-11-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-11-23 | 1995-05-25 | 1995-11-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-11-23 | 1999-05-25 | 1999-11-24 | $7700.00 | Window Closed / Lapsed |