GB1214371A - Digital canonical filter - Google Patents

Digital canonical filter

Info

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
Application number
GB747468A
Inventor
Alan Jason Deerfield
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Raytheon Co
Original Assignee
Raytheon Co
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Priority to US607562A priority Critical patent/US3370292A/en
Application filed by Raytheon Co filed Critical Raytheon Co
Priority to GB747468A priority patent/GB1214371A/en
Priority to NL6802332A priority patent/NL6802332A/xx
Priority to BE710966D priority patent/BE710966A/xx
Priority to DE19681616410 priority patent/DE1616410A1/en
Priority to FR1554437D priority patent/FR1554437A/fr
Publication of GB1214371A publication Critical patent/GB1214371A/en
Expired legal-status Critical Current

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 Hardware Design (AREA)
  • Mathematical Physics (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • General Physics & Mathematics (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.
GB747468A 1967-01-05 1968-02-15 Digital canonical filter Expired GB1214371A (en)

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
BE710966D BE710966A (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
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
NL6802332A NL6802332A (en) 1968-02-15 1968-02-19
BE710966 1968-02-19
DER0048039 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)

* Cited by examiner, † Cited by third party
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)

* Cited by examiner, † Cited by third party
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

Cited By (2)

* Cited by examiner, † Cited by third party
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
NL6802332A (en) 1969-08-21
BE710966A (en) 1968-07-01
FR1554437A (en) 1969-01-17
DE1616410A1 (en) 1971-04-15

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Legal Events

Date Code Title Description
PS Patent sealed
PLNP Patent lapsed through nonpayment of renewal fees