EP0121537A1 - Reduction a l'enregistrement du bruit provoque par des vibrations - Google Patents

Reduction a l'enregistrement du bruit provoque par des vibrations

Info

Publication number
EP0121537A1
EP0121537A1 EP83903151A EP83903151A EP0121537A1 EP 0121537 A1 EP0121537 A1 EP 0121537A1 EP 83903151 A EP83903151 A EP 83903151A EP 83903151 A EP83903151 A EP 83903151A EP 0121537 A1 EP0121537 A1 EP 0121537A1
Authority
EP
European Patent Office
Prior art keywords
signal
channel
recorded
recording
input
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.)
Withdrawn
Application number
EP83903151A
Other languages
German (de)
English (en)
Inventor
Neil Robert Hamilton
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.)
Commonwealth of Australia
Original Assignee
Commonwealth of Australia
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 Commonwealth of Australia filed Critical Commonwealth of Australia
Publication of EP0121537A1 publication Critical patent/EP0121537A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B20/00—Signal processing not specific to the method of recording or reproducing; Circuits therefor
    • G11B20/24—Signal processing not specific to the method of recording or reproducing; Circuits therefor for reducing noise

Definitions

  • This invention relates to an arrangement for use with recording devices using discs or tape to reduce background noise caused by vibrations to the recording apparatus.
  • the signal In field applications, particularly where signal monitor ing is being carried out, the signal is often subject to distortion by vibrations which the recording apparatus is subjected to. These vibrations affect the frequency of the signal and make analysis and monitoring difficult.
  • This method requires a delay of a portion of the signal and comparing the signal with the delayed signal to cancel out the signal to leave a noise signal which is subsequently subtracted from the information signal. This specification does admit that tape speed corrections will need to be made where motor speed variations exist.
  • An object of the present invention is to provide a simpler means of reducing noise.
  • the present invention provides an informatio transmission system in which an input information signal is recorded in a first channel of a record medium and a second constant input signal is recorded in a second channel of said record medium characterized in that the first recorded input signal is divided by the second recorded signal to provide an output signal which is substantially free of any noise produced by vibrations to which the system is subjected.
  • This invention is based on the discovery that the vibra- tions to the system have a multiplying effect on the input signal.
  • figure 1 is a block diagram of the preferred recording system of thi invention
  • figure lb is a block diagram of the playback system
  • figures 2a and 2b illustrate portions of the circuits respectively of the preferred form of the invention.
  • the system is presented as an attachment to a recording device, in this case, a tape recorder 20 with stereo output.
  • the first channel carries the information signal while the second channel carries the constant reference signal.
  • an amplifier 21 is required to amplify the signal.
  • the output of the voltage to frequency converter 22 (voltage controlled oscillator) is not constrained to be of any particular shape. The only con ⁇ straint is that after replay from the tape recorder, a wave- shape which is compatible with the frequency to voltage converter is obtained. This also applies to the reference oscillator 23 which generates the reference signal 54.
  • the voltage to frequency 22 and frequency to voltage convert ⁇ ers 25,26 are only required when used with tape recorders tha do not contain FM recording facilities.
  • the first channel (input channel) voltage to frequency converter 22 is only required if the input signal frequency range is incompatible with the tape recorder being used.
  • a low pass filter is used to remove any unwanted frequencies in the lower range, but, in general, this will depend on the purpose to which the signal receiving system is being put.
  • An inverter is used to invert the reference signal which is subsequently divided into the information signal in the divider circuit to give the noise reduced output signal.
  • the difference signal SI is amplified by the required amount and applied to the voltage to frequency converter (VFC) input (S2).
  • VFC voltage to frequency converter
  • This low frequency signal is converted to a signal of convenient frequency (S3) and applied to channel 1 of the tape recorder.
  • the signal S3, may be adjusted to a particular frequency at zero input voltage and also for scale factor, i.e. change in frequency for change in voltage level.
  • a suitable frequency is selected for the reference oscillator Signal (S4) and applied to the tape recorder second channel.
  • the signals from both channels are recon ⁇ verted by the frequency to voltage converters 25 and 26 to low frequency signals (S7, S8).
  • the signals from the recorder 55 and 56 are amplified by amplifiers 27 and 28 before conversion.
  • the input channel signal (S7) would, if not corrupted by tape speed variations, be identical to the input signal (S2).
  • the reference channel signal (S7) would ideally be a constant DC voltage which is converted to a negative DC voltage (S9) for compatibility with the "X" terminal of the AD533 divider circuit 29.
  • the divider output signal (S10) will be an identical replica of the input signal S2 free of tape speed variation induced errors.
  • the inverter is only required with a certain type of divider circuit (of which the AD533 is one). It is possible to use dividers for which the inverter is not necessary.

Landscapes

  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Signal Processing Not Specific To The Method Of Recording And Reproducing (AREA)

Abstract

Système pour l'enregistrement et la reproduction d'informations dans lequel le bruit provoqué par les vibrations du système est supprimé. Deux canaux sont utilisés, l'un pour enregistrer les informations d'entrée et le second pour enregistrer un signal d'entrée constant. Le signal du premier canal est alors divisé par le signal du second canal pour donner un signal de sortie exempt de bruit induit par des vibrations.
EP83903151A 1982-10-07 1983-10-05 Reduction a l'enregistrement du bruit provoque par des vibrations Withdrawn EP0121537A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
AUPF623282 1982-10-07
AU6232/82 1982-10-07

Publications (1)

Publication Number Publication Date
EP0121537A1 true EP0121537A1 (fr) 1984-10-17

Family

ID=3769778

Family Applications (1)

Application Number Title Priority Date Filing Date
EP83903151A Withdrawn EP0121537A1 (fr) 1982-10-07 1983-10-05 Reduction a l'enregistrement du bruit provoque par des vibrations

Country Status (3)

Country Link
EP (1) EP0121537A1 (fr)
IT (1) IT1171725B (fr)
WO (1) WO1984001656A1 (fr)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2923161B2 (ja) * 1993-03-12 1999-07-26 シャープ株式会社 磁気テープ再生装置

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2807797A (en) * 1955-03-14 1957-09-24 California Research Corp Noise elimination in fm recording
US2951243A (en) * 1958-05-28 1960-08-30 Daniel J Torpy Tape playback system
US3337693A (en) * 1964-06-30 1967-08-22 Silverstein Abraham Chopper demodulator system for direct-record tape recorders
FR2088882A5 (fr) * 1970-04-28 1972-01-07 Thomson Csf
GB1409715A (en) * 1971-09-28 1975-10-15 Lucas Industries Ltd Method ofand apparatus for recording and decoding frequency modulated signals
US3803630A (en) * 1972-05-22 1974-04-09 Signa Signer Inc Apparatus for recording and reproducing handwriting
US4136364A (en) * 1977-07-01 1979-01-23 Signature Systems, Inc. Multi-state wow and flutter reduction system and method
US4291343A (en) * 1977-08-29 1981-09-22 Riddle H S Jun Frequency-ratio apparatus
GB2061647A (en) * 1979-10-26 1981-05-13 Emi Ltd Frequency demodulator

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO8401656A1 *

Also Published As

Publication number Publication date
IT1171725B (it) 1987-06-10
IT8323200A0 (it) 1983-10-07
WO1984001656A1 (fr) 1984-04-26

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Legal Events

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PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

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AK Designated contracting states

Designated state(s): BE CH DE FR GB LI NL SE

STAA Information on the status of an ep patent application or granted ep patent

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18D Application deemed to be withdrawn

Effective date: 19840911

RIN1 Information on inventor provided before grant (corrected)

Inventor name: HAMILTON, NEIL, ROBERT