GB897980A - Improvements in or relating to carrier frequency telegraph systems - Google Patents

Improvements in or relating to carrier frequency telegraph systems

Info

Publication number
GB897980A
GB897980A GB3003759A GB3003759A GB897980A GB 897980 A GB897980 A GB 897980A GB 3003759 A GB3003759 A GB 3003759A GB 3003759 A GB3003759 A GB 3003759A GB 897980 A GB897980 A GB 897980A
Authority
GB
United Kingdom
Prior art keywords
frequency
filter
telegraph
channel
band
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
GB3003759A
Inventor
William Francis S Chittleburgh
Eric Robert Aylott
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.)
STC PLC
Original Assignee
Standard Telephone and Cables PLC
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 claimed from GB2829846A external-priority patent/GB620715A/en
Application filed by Standard Telephone and Cables PLC filed Critical Standard Telephone and Cables PLC
Priority to GB3003759A priority Critical patent/GB897980A/en
Priority to BE609060A priority patent/BE609060A/en
Publication of GB897980A publication Critical patent/GB897980A/en
Expired legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00—Arrangements affording multiple use of the transmission path
    • H04L5/02—Channels characterised by the type of signal
    • H04L5/06—Channels characterised by the type of signal the signals being represented by different frequencies
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/10—Frequency-modulated carrier systems, i.e. using frequency-shift keying
    • H04L27/16—Frequency regulation arrangements

Landscapes

  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Radio Relay Systems (AREA)

Abstract

897,980. Multiplex transmission systems. STANDARD TELEPHONES & CABLES Ltd. Sept. 3, 1959, No. 30037/59. Addition to 620,715. Class 40 (4). [Also in Groups XL (b) and XL (c)] A multi-channel carrier frequency telegraph modulation system for operation over a communication path which is liable to introduce a change in the mean carrier frequency of each channel includes means at the transmitting end for the transmission with the telegraph signals of a pilot wave having a frequency outside the band of frequencies occupied by the telegraph signals but within the frequency band of the carrier channel, and at the receiving end means for correcting the change in the mean carrier frequency for each channel by the received pilot wave for introducing a frequencyshift which is substantially equal and opposite to the frequency-shift introduced by said communication path whereby the last mentioned frequency-shift is substantially neutralized. In the diagrammatic arrangement of Fig. 1, the modulated output of a transmitter including the pilot frequency is received over a line 1, passes to a carrier telephone receiving system 7, and after passage through a frequency corrector 8 is applied to filters 9 leading to associated telegraph demodulators 10. The corrector 8, Fig. 2, included between the system 7 and the filter 9 comprises a modulator 13 to which is applied the frequency #1 from an oscillator 14 and, for example, f + df, where f is one of the telegraph frequencies and df is the frequency shift introduced by the telephone channel and a filter 15 passes the lower side band #1 - (#+d#) to the demodulator 20. A filter 22 passes the received pilot frequency F + df to a modulator 23 fed with the frequency #1 from the oscillator 14. The lower side-band, i.e. #1 - (F + df) from the modulator 23 is selected by a filter 16 and passed to a modulator 17 which receives the pilot frequency F from the oscillator 18 and a filter 19 passes the upper side band i.e. #1 - df which is applied as the second input to the demodulator 20. A filter 21 selects from the output of the demodulator 20 the lower side band #1 - d# - [#1 - (f + df] i.e., f which is independent of the frequency shift df and is passed by a filter 21 to a terminal 12 leading to the telegraph channel filters.
GB3003759A 1946-09-20 1959-09-03 Improvements in or relating to carrier frequency telegraph systems Expired GB897980A (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
GB3003759A GB897980A (en) 1946-09-20 1959-09-03 Improvements in or relating to carrier frequency telegraph systems
BE609060A BE609060A (en) 1959-09-03 1961-10-12 Improvements to Frequency Slip Telegraphy Systems

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB2829846A GB620715A (en) 1946-09-20 1946-09-20 Improvements in or relating to electric carrier frequency modulation system
GB3003759A GB897980A (en) 1946-09-20 1959-09-03 Improvements in or relating to carrier frequency telegraph systems

Publications (1)

Publication Number Publication Date
GB897980A true GB897980A (en) 1962-06-06

Family

ID=26259303

Family Applications (1)

Application Number Title Priority Date Filing Date
GB3003759A Expired GB897980A (en) 1946-09-20 1959-09-03 Improvements in or relating to carrier frequency telegraph systems

Country Status (1)

Country Link
GB (1) GB897980A (en)

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