GB1023974A - Improvements in or relating to recording systems or apparatus - Google Patents

Improvements in or relating to recording systems or apparatus

Info

Publication number
GB1023974A
GB1023974A GB4361862A GB4361862A GB1023974A GB 1023974 A GB1023974 A GB 1023974A GB 4361862 A GB4361862 A GB 4361862A GB 4361862 A GB4361862 A GB 4361862A GB 1023974 A GB1023974 A GB 1023974A
Authority
GB
United Kingdom
Prior art keywords
pulses
output
transistor
square wave
tracks
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
GB4361862A
Inventor
Derek John Mauchel
William Denis Woodman
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.)
Communications Patents Ltd
Original Assignee
Communications Patents 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 Communications Patents Ltd filed Critical Communications Patents Ltd
Priority to GB4361862A priority Critical patent/GB1023974A/en
Publication of GB1023974A publication Critical patent/GB1023974A/en
Expired legal-status Critical Current

Links

Classifications

    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04NPICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N5/00Details of television systems
    • H04N5/76Television signal recording
    • H04N5/91Television signal processing therefor
    • H04N5/92Transformation of the television signal for recording, e.g. modulation, frequency changing; Inverse transformation for playback

Landscapes

  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Networks Using Active Elements (AREA)

Abstract

1,023,974. Local circuits for magnetic recording &c. apparatus; electric analogue calculating. COMMUNICATIONS PATENTS Ltd. Nov. 4, 1963 [Nov. 19, 1962], No. 43618/62. Headings G4G and G5K. [Also in Divisions H3 and H4] Variations in signals reproduced from a recording medium due to variations in speed of the medium are corrected by a correction signal derived from a constant frequency signal recorded on the medium. Referring to Fig. 2 the magnetic tape 30 carries eight tracks, a speech track 1, a reference track 4 containing a constant frequency square wave, and other tracks such as 2 containing a square wave frequency modulated in accordance with the data fed to the original recording circuit. The outputs from tracks 2 and 4 are fed to pulseshaping units 14 and 15 and then to monostable multivibrators 16 and 17 which produce negative pulses of uniform width at twice the input frequencies. These pulses are integrated in filters 18 and 19 to produce voltages V m and V, respectively. Errors in tape speed affect V m and V, in the same ratio and the voltage V r is used to correct V m . V m is used in unit 21 to modulate the pulse width of square wave pulses of constant frequency from a generator 20, the length T m of the pulses being inversely proportional to V m . V r amplitude modulates the pulses in unit 22 to give an output propor- V r tional to-, and this output is integrated by V m a filter 23 and passed through a D.C. amplifier 24 to an output device 26 which may be a voltmeter or a pen-type recorder. Electric analogue calculating.-In Fig. 3 a mono-stable multivibrator is triggered by a square wave input f 0 applied to terminal 60, and its timing capacitor 45 is discharged through a constant current generator 52 controlled by an input voltage V m at transistor 54. Thus the length T m of the negative-going part of the output pulses is inversely proportional to V m .-These pulses pass to a switching circuit, Fig. 4, wherein the output of transistor 74 is clamped to an input voltage V, for the pulse duration when the transistor is non-conducting. The output of transistor 74 passes to emitterfollower circuits 83 and 86 and comprises pulses of a width inversely proportional to V m and of an amplitude proportional to V r .-The final output may be integrated in a filter to produce a voltage proportional to V r /V m-
GB4361862A 1962-11-19 1962-11-19 Improvements in or relating to recording systems or apparatus Expired GB1023974A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB4361862A GB1023974A (en) 1962-11-19 1962-11-19 Improvements in or relating to recording systems or apparatus

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB4361862A GB1023974A (en) 1962-11-19 1962-11-19 Improvements in or relating to recording systems or apparatus

Publications (1)

Publication Number Publication Date
GB1023974A true GB1023974A (en) 1966-03-30

Family

ID=10429559

Family Applications (1)

Application Number Title Priority Date Filing Date
GB4361862A Expired GB1023974A (en) 1962-11-19 1962-11-19 Improvements in or relating to recording systems or apparatus

Country Status (1)

Country Link
GB (1) GB1023974A (en)

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