GB1512226A - Facsimile receiver - Google Patents

Facsimile receiver

Info

Publication number
GB1512226A
GB1512226A GB4789175A GB4789175A GB1512226A GB 1512226 A GB1512226 A GB 1512226A GB 4789175 A GB4789175 A GB 4789175A GB 4789175 A GB4789175 A GB 4789175A GB 1512226 A GB1512226 A GB 1512226A
Authority
GB
United Kingdom
Prior art keywords
carrier
signals
error signal
circuit
facsimile receiver
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
GB4789175A
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.)
Xerox Corp
Original Assignee
Xerox Corp
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 Xerox Corp filed Critical Xerox Corp
Priority to GB4789175A priority Critical patent/GB1512226A/en
Publication of GB1512226A publication Critical patent/GB1512226A/en
Expired legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
    • H04N1/00095—Systems or arrangements for the transmission of the picture signal
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03D—DEMODULATION OR TRANSFERENCE OF MODULATION FROM ONE CARRIER TO ANOTHER
    • H03D1/00—Demodulation of amplitude-modulated oscillations
    • H03D1/22—Homodyne or synchrodyne circuits
    • H03D1/24—Homodyne or synchrodyne circuits for demodulation of signals wherein one sideband or the carrier has been wholly or partially suppressed
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03L—AUTOMATIC CONTROL, STARTING, SYNCHRONISATION OR STABILISATION OF GENERATORS OF ELECTRONIC OSCILLATIONS OR PULSES
    • H03L7/00—Automatic control of frequency or phase; Synchronisation
    • H03L7/06—Automatic control of frequency or phase; Synchronisation using a reference signal applied to a frequency- or phase-locked loop
    • H03L7/08—Details of the phase-locked loop

Landscapes

  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Power Engineering (AREA)
  • Facsimile Image Signal Circuits (AREA)
  • Digital Transmission Methods That Use Modulated Carrier Waves (AREA)

Abstract

1512226 AFC systems XEROX CORP 20 Nov 1975 47891/75 Heading H3A A facsimile receiver for receiving carrier suppressed amplitude modulated incoming signals comprises a demodulator 17 and a phase lock circuit including a phase comparator 32, an oscillator 33 controlled by the error signal of 32 for deriving demodulating signals for 17 and a circuit 37 responsive to the incoming signals to restrict the application of the error signal to periods where there is a reliable carrier signal present. If the carrier drift due to variations in transmission lines or individual carrier generators is appreciable or if the carrier appears at instants of large noise, the oscillator may lock incorrectly to a lower sideband or a line transient. The circuit 37 prevents the application of the error signal, if the period of incoming signals (including carrier signals) is more than a predetermined period. Although spurious high frequency signals could be arranged to be eliminated by 37, they are in fact eliminated by the transmission line and line filters. Fig. 1 (not shown) relates to a facsimile receiver arrangement.
GB4789175A 1975-11-20 1975-11-20 Facsimile receiver Expired GB1512226A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB4789175A GB1512226A (en) 1975-11-20 1975-11-20 Facsimile receiver

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB4789175A GB1512226A (en) 1975-11-20 1975-11-20 Facsimile receiver

Publications (1)

Publication Number Publication Date
GB1512226A true GB1512226A (en) 1978-05-24

Family

ID=10446622

Family Applications (1)

Application Number Title Priority Date Filing Date
GB4789175A Expired GB1512226A (en) 1975-11-20 1975-11-20 Facsimile receiver

Country Status (1)

Country Link
GB (1) GB1512226A (en)

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Legal Events

Date Code Title Description
PS Patent sealed
746 Register noted 'licences of right' (sect. 46/1977)
PCNP Patent ceased through non-payment of renewal fee

Effective date: 19931120