GB990680A - Improvements in noise cancellers for signal processing systems - Google Patents
Improvements in noise cancellers for signal processing systemsInfo
- Publication number
- GB990680A GB990680A GB2008461A GB2008461A GB990680A GB 990680 A GB990680 A GB 990680A GB 2008461 A GB2008461 A GB 2008461A GB 2008461 A GB2008461 A GB 2008461A GB 990680 A GB990680 A GB 990680A
- Authority
- GB
- United Kingdom
- Prior art keywords
- mixer
- channel
- output
- signals
- filter
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
- G01S7/28—Details of pulse systems
- G01S7/2813—Means providing a modification of the radiation pattern for cancelling noise, clutter or interfering signals, e.g. side lobe suppression, side lobe blanking, null-steering arrays
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q3/00—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system
- H01Q3/26—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system varying the relative phase or relative amplitude of energisation between two or more active radiating elements; varying the distribution of energy across a radiating aperture
- H01Q3/2605—Array of radiating elements provided with a feedback control over the element weights, e.g. adaptive arrays
- H01Q3/2611—Means for null steering; Adaptive interference nulling
- H01Q3/2629—Combination of a main antenna unit with an auxiliary antenna unit
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/06—Receivers
- H04B1/10—Means associated with receiver for limiting or suppressing noise or interference
- H04B1/12—Neutralising, balancing, or compensation arrangements
Landscapes
- Engineering & Computer Science (AREA)
- Radar, Positioning & Navigation (AREA)
- Remote Sensing (AREA)
- Computer Networks & Wireless Communication (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Signal Processing (AREA)
- Radar Systems Or Details Thereof (AREA)
Abstract
990,680. Radio receiving systems; radar; aerials. GENERAL ELECTRIC CO. June 2, 1961, No. 20084/61. Headings H4A, H4D and H4L. A noise canceller for a signal processing system comprises a main signal transmission channel and an auxiliary signal transmission channel, means for adjusting the amplitude and phase of interference signals in the auxiliary channel to equal the amplitude and phase of interference in the main channel, and means for subtracting the adjusted signals in the auxiliary channel from the signals in the main channel. Fig. 1a shows a circuit for reducing the effect of noise jamming in a radar receiver. Signals from a directional aerial 10 are mixed with a local oscillation in mixer 14 and passed through a subtraction circuit 22 and a bandpass filter 23 to an output terminal. Jamming signals from a non-directional aerial 12 are mixed in unit 18 with a local oscillation offset from that of the main channel. One output of mixer 18 is fed through a band-pass filter 27 to a mixer 24 where it is mixed with the output of the main channel; the output of mixer 24 is passed through a narrow band filter 26 to provide a signal at a frequency equal to the difference between the two intermediate frequencies and having an amplitude proportional to the average power of the jammer. The phase of this signal is adjusted to that of the main channel by mixing it with a second output of mixer 18 in mixer 28. The output of mixer 28 is introduced to the radar I.F. channel through subtraction circuit 22 forming a non-linear closed loop providing automatic gain adjustment so that the residual jamming signal approaches zero in the radar I.F. channel. The speed of response of the system is dependent on the loop gain and the bandwidth of filter 26. Since loop gain is proportional to average power the loop cancels jamming signals which have high average power, while it is relatively insensitive to echoes which have low average power. In a modification, Fig. 2 (not shown), aerial 12 is replaced by three non- directional aerials equally spaced in a linear array for side lobe cancelling. The outputs of the aerials are respectively mixed with local oscillations, the frequencies of which form an arithmetical progression, and the sum of the outputs of the mixers replaces the output of mixer 18 in Fig. 1a. The filters 23 and 27 are omitted and filter 26 is replaced by three narrow band filters in parallel. The pattern of the non-directional array is caused to scan by phasing of array outputs.
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US810961A US3202990A (en) | 1959-05-04 | 1959-05-04 | Intermediate frequency side-lobe canceller |
GB2008461A GB990680A (en) | 1961-06-02 | 1961-06-02 | Improvements in noise cancellers for signal processing systems |
FR866665A FR1440603A (en) | 1961-06-02 | 1961-06-30 | Device enhancements to suppress interfering signals in signal receiving assemblies |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB2008461A GB990680A (en) | 1961-06-02 | 1961-06-02 | Improvements in noise cancellers for signal processing systems |
Publications (1)
Publication Number | Publication Date |
---|---|
GB990680A true GB990680A (en) | 1965-04-28 |
Family
ID=10140106
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB2008461A Expired GB990680A (en) | 1959-05-04 | 1961-06-02 | Improvements in noise cancellers for signal processing systems |
Country Status (1)
Country | Link |
---|---|
GB (1) | GB990680A (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2123260A (en) * | 1982-07-02 | 1984-01-25 | Philips Nv | Arrangement for the suppression of signal interference |
-
1961
- 1961-06-02 GB GB2008461A patent/GB990680A/en not_active Expired
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2123260A (en) * | 1982-07-02 | 1984-01-25 | Philips Nv | Arrangement for the suppression of signal interference |
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