GB1529563A - Frequency search circuits - Google Patents

Frequency search circuits

Info

Publication number
GB1529563A
GB1529563A GB957957A GB957957A GB1529563A GB 1529563 A GB1529563 A GB 1529563A GB 957957 A GB957957 A GB 957957A GB 957957 A GB957957 A GB 957957A GB 1529563 A GB1529563 A GB 1529563A
Authority
GB
United Kingdom
Prior art keywords
signal
noise
pulses
frequency
regular
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
GB957957A
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.)
British Aircraft Corp Ltd
Original Assignee
British Aircraft Corp Ltd
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
Application filed by British Aircraft Corp Ltd filed Critical British Aircraft Corp Ltd
Priority to GB957957A priority Critical patent/GB1529563A/en
Publication of GB1529563A publication Critical patent/GB1529563A/en
Expired legal-status Critical Current

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
    • 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
    • G01S13/58—Velocity or trajectory determination systems; Sense-of-movement determination systems
    • G01S13/585—Velocity or trajectory determination systems; Sense-of-movement determination systems processing the video signal in order to evaluate or display the velocity value
    • G01S13/586—Velocity or trajectory determination systems; Sense-of-movement determination systems processing the video signal in order to evaluate or display the velocity value using, or combined with, frequency tracking means

Landscapes

  • Engineering & Computer Science (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
  • Multimedia (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Radar Systems Or Details Thereof (AREA)

Abstract

1529563 Electromagnetic and inductive field communication pulse modulation BRITISH AIRCRAFT CORP (OPERATING) Ltd 19 March 1958 [22 March 1957] 9579/57 Heading H4L In a Doppler radar system a range of frequencies is scanned and the search circuit distinguishes between noise and the regular signal to which it must "lock on". The input signal at the receiver is amplified to a predetermined stabilized level, by an automatically operated gain control. The stabilized level amplitude is greater than the amplitude of the regular signal but is less than the noise peak amplitude. Thus, noise is detected when occasional noise peaks overswing the stabilization level and as these instants pulses, of fixed duration, are produced. The pulses are applied to a spectrum analyser which is stepped from one frequency band to the next by each pulse and the frequency search continues until pulses cease to be produced, that is, when the required regular signal is reached. Where the required signal has a variable frequency, changes in frequency are "tracked" by an automatic frequency control loop which produces a D.C. control voltage after the required signal has been found. Alternatively, the first differential of the input signal may be employed to produce the control pulses, the noise signal differential having a larger amplitude than that of the required signal. In a further arrangement, a predetermined level is chosen near the zero of the amplified signal. With this, the regular required signal, the envelope does not approach zero while the noise signal has frequent near-zero values which cause control pulses to be generated.
GB957957A 1958-03-19 1958-03-19 Frequency search circuits Expired GB1529563A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB957957A GB1529563A (en) 1958-03-19 1958-03-19 Frequency search circuits

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB957957A GB1529563A (en) 1958-03-19 1958-03-19 Frequency search circuits

Publications (1)

Publication Number Publication Date
GB1529563A true GB1529563A (en) 1978-10-25

Family

ID=9874725

Family Applications (1)

Application Number Title Priority Date Filing Date
GB957957A Expired GB1529563A (en) 1958-03-19 1958-03-19 Frequency search circuits

Country Status (1)

Country Link
GB (1) GB1529563A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4679048A (en) * 1985-04-25 1987-07-07 Grumman Aerospace Corporation Adaptive spread spectrum radar

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4679048A (en) * 1985-04-25 1987-07-07 Grumman Aerospace Corporation Adaptive spread spectrum radar

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Legal Events

Date Code Title Description
CSNS Application of which complete specification have been accepted and published, but patent is not sealed