GB997893A - Frequency-shift keying arrangement - Google Patents

Frequency-shift keying arrangement

Info

Publication number
GB997893A
GB997893A GB2578163A GB2578163A GB997893A GB 997893 A GB997893 A GB 997893A GB 2578163 A GB2578163 A GB 2578163A GB 2578163 A GB2578163 A GB 2578163A GB 997893 A GB997893 A GB 997893A
Authority
GB
United Kingdom
Prior art keywords
capacitor
key
frequency
transistor
emitter
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
GB2578163A
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
Application filed by Standard Telephone and Cables PLC filed Critical Standard Telephone and Cables PLC
Publication of GB997893A publication Critical patent/GB997893A/en
Expired legal-status Critical Current

Links

Classifications

    • 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
    • H04L27/12—Modulator circuits; Transmitter circuits

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Sub-Exchange Stations And Push- Button Telephones (AREA)
  • Inductance-Capacitance Distribution Constants And Capacitance-Resistance Oscillators (AREA)
  • Stabilization Of Oscillater, Synchronisation, Frequency Synthesizers (AREA)

Abstract

997,893. Frequency modulation. STANDARD TELEPHONES & CABLES Ltd. June 28, 1963 [July 2, 1962], No. 25781/63. Headings H3R and H4P. In F.S.K. telegraphy a capacitor is shunted across the tuned circuit of an oscillator, to shift its frequency, by a transistor switch with emitter/collector conduction path in series with the capacitor. In Fig. 3, a transistor T is normally biased to conduct when key Ta is open, but when the key is closed the base and emitter both have earth potential and the transistor is blocked to render ineffective the capacitor (not shown) in its collector lead connected with the oscillator tuned circuit. Network L 1 , C 3 , C 4 eliminates keying transients by converting the square wave keying voltage into trapezoidal form. Rectifier G 1 and resistors R 1 , R 2 , R 3 ensure that the impedance presented to the input end of the network is the same, provided R 1 = R 2 , whether the key Ta is up or down.
GB2578163A 1962-07-02 1963-06-28 Frequency-shift keying arrangement Expired GB997893A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DEST019426 1962-07-02

Publications (1)

Publication Number Publication Date
GB997893A true GB997893A (en) 1965-07-14

Family

ID=7458198

Family Applications (2)

Application Number Title Priority Date Filing Date
GB3855756A Expired GB804411A (en) 1962-07-02 1956-12-18 Improvements in or relating to telegraph frequency modulators
GB2578163A Expired GB997893A (en) 1962-07-02 1963-06-28 Frequency-shift keying arrangement

Family Applications Before (1)

Application Number Title Priority Date Filing Date
GB3855756A Expired GB804411A (en) 1962-07-02 1956-12-18 Improvements in or relating to telegraph frequency modulators

Country Status (1)

Country Link
GB (2) GB804411A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5612650A (en) * 1994-09-14 1997-03-18 Kabushiki Kaisha Tokai Rika Denki Seisakusho Transmitting device for a frequency modulated digital transmission signal

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5612650A (en) * 1994-09-14 1997-03-18 Kabushiki Kaisha Tokai Rika Denki Seisakusho Transmitting device for a frequency modulated digital transmission signal

Also Published As

Publication number Publication date
GB804411A (en) 1958-11-12

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