GB1214371A - Digital canonical filter - Google Patents
Digital canonical filterInfo
- Publication number
- GB1214371A GB1214371A GB747468A GB747468A GB1214371A GB 1214371 A GB1214371 A GB 1214371A GB 747468 A GB747468 A GB 747468A GB 747468 A GB747468 A GB 747468A GB 1214371 A GB1214371 A GB 1214371A
- Authority
- GB
- United Kingdom
- Prior art keywords
- filter
- values
- digital
- registers
- reference table
- 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
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H17/00—Networks using digital techniques
- H03H17/02—Frequency selective networks
- H03H17/04—Recursive filters
-
- 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
- G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
- G01S13/02—Systems using reflection of radio waves, e.g. primary radar systems; Analogous systems
- G01S13/50—Systems of measurement based on relative movement of target
- G01S13/52—Discriminating between fixed and moving objects or between objects moving at different speeds
- G01S13/522—Discriminating between fixed and moving objects or between objects moving at different speeds using transmissions of interrupted pulse modulated waves
- G01S13/524—Discriminating between fixed and moving objects or between objects moving at different speeds using transmissions of interrupted pulse modulated waves based upon the phase or frequency shift resulting from movement of objects, with reference to the transmitted signals, e.g. coherent MTi
- G01S13/526—Discriminating between fixed and moving objects or between objects moving at different speeds using transmissions of interrupted pulse modulated waves based upon the phase or frequency shift resulting from movement of objects, with reference to the transmitted signals, e.g. coherent MTi performing filtering on the whole spectrum without loss of range information, e.g. using delay line cancellers or comb filters
Landscapes
- Engineering & Computer Science (AREA)
- Radar, Positioning & Navigation (AREA)
- Remote Sensing (AREA)
- Physics & Mathematics (AREA)
- Computer Networks & Wireless Communication (AREA)
- General Physics & Mathematics (AREA)
- Computer Hardware Design (AREA)
- Mathematical Physics (AREA)
- Radar Systems Or Details Thereof (AREA)
- Complex Calculations (AREA)
Abstract
1,214,371. Pulse radar; active filters. RAYTHEON CO. 15 Feb., 1968, No. 7474/68. Headings H3U and H4D. A known "digital canonical filter" comprises an input adder feeding into a series of registers (each register acts as a digital delay device and represents a pole or a zero of the filter) from which weighted-by B factors-are fed back to the input adder and an output adder fed with further weighted-by A factors-outputs from the registers, Fig. 1 (not shown). A single such filter cannot perform different filtering operations and according to the present invention a reference table is provided to store all possible values of a set of variables weighted by a corresponding set of weighting constants. The invention permits a reduction in the number of multiplications to be carried out and achieves high speed operation. Considering the embodiment of Fig. 2 if B 1 is specified and X N-1 (the variable provided by register 20) is an eightbit number only 256 products of B 1 X N-1 are possible; a magnetic storage reference table 10 consists of 256 words, the products corresponding to B 1 being written into a portion of each word and stored in column 12 and similarly for B 2 , B 3 , B 4 . The values of variables X N-1 . . . X N-4 are identical to the values of X N at a time one . . . four cycles earlier respectively i.e. XN at time N becomes X N-1 at time N + 1. The register arrangement is as depicted. Similar considerations apply to the A-products. An embodiment utilizing fewer components utilizes less registers but more adders, Fig. 3 (not shown). Radar.-The radar bi-polar video output signal is fed to an analogue-to-digital converter (122, Fig. 4 (not shown)), the converter output is temporarily stored in a digital memory (124) and a succession of stored values from the memory are read out in any desired sequence into the canonical filter. Targets in intense clutter can be detected; a magnetic tape unit (128) fills the reference table (130) with desired values: for example one set of filter characteristics may be used in clear weather and a different set in the event of rain. Other applications mentioned are speech and frequency spectrum analysis.
Priority Applications (6)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US607562A US3370292A (en) | 1967-01-05 | 1967-01-05 | Digital canonical filter |
GB747468A GB1214371A (en) | 1968-02-15 | 1968-02-15 | Digital canonical filter |
NL6802332A NL6802332A (en) | 1968-02-15 | 1968-02-19 | |
DE19681616410 DE1616410A1 (en) | 1968-02-15 | 1968-02-19 | Canonical digital filter and circuit with such a filter |
BE710966D BE710966A (en) | 1968-02-15 | 1968-02-19 | |
FR1554437D FR1554437A (en) | 1968-02-15 | 1968-02-20 |
Applications Claiming Priority (5)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB747468A GB1214371A (en) | 1968-02-15 | 1968-02-15 | Digital canonical filter |
BE710966 | 1968-02-19 | ||
DER0048039 | 1968-02-19 | ||
NL6802332A NL6802332A (en) | 1968-02-15 | 1968-02-19 | |
FR140436 | 1968-02-20 |
Publications (1)
Publication Number | Publication Date |
---|---|
GB1214371A true GB1214371A (en) | 1970-12-02 |
Family
ID=27507687
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB747468A Expired GB1214371A (en) | 1967-01-05 | 1968-02-15 | Digital canonical filter |
Country Status (5)
Country | Link |
---|---|
BE (1) | BE710966A (en) |
DE (1) | DE1616410A1 (en) |
FR (1) | FR1554437A (en) |
GB (1) | GB1214371A (en) |
NL (1) | NL6802332A (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE2451235A1 (en) * | 1973-12-11 | 1975-06-12 | Ibm | CIRCUIT ARRANGEMENT FOR A DIGITAL FILTER |
GB2151426A (en) * | 1983-12-09 | 1985-07-17 | Plessey Co Plc | Radar clutter filter |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2418579A2 (en) * | 1977-03-09 | 1979-09-21 | Onera (Off Nat Aerospatiale) | RECURRING DIGITAL FILTER WITH COEFFICIENTS IN REDUCED POWER COMBINATION BY TWO |
-
1968
- 1968-02-15 GB GB747468A patent/GB1214371A/en not_active Expired
- 1968-02-19 NL NL6802332A patent/NL6802332A/xx unknown
- 1968-02-19 BE BE710966D patent/BE710966A/xx unknown
- 1968-02-19 DE DE19681616410 patent/DE1616410A1/en active Pending
- 1968-02-20 FR FR1554437D patent/FR1554437A/fr not_active Expired
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE2451235A1 (en) * | 1973-12-11 | 1975-06-12 | Ibm | CIRCUIT ARRANGEMENT FOR A DIGITAL FILTER |
GB2151426A (en) * | 1983-12-09 | 1985-07-17 | Plessey Co Plc | Radar clutter filter |
Also Published As
Publication number | Publication date |
---|---|
FR1554437A (en) | 1969-01-17 |
NL6802332A (en) | 1969-08-21 |
DE1616410A1 (en) | 1971-04-15 |
BE710966A (en) | 1968-07-01 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
PS | Patent sealed | ||
PLNP | Patent lapsed through nonpayment of renewal fees |