GB775564A - Improvements in or relating to telephone subscribers' instruments - Google Patents

Improvements in or relating to telephone subscribers' instruments

Info

Publication number
GB775564A
GB775564A GB360254A GB360254A GB775564A GB 775564 A GB775564 A GB 775564A GB 360254 A GB360254 A GB 360254A GB 360254 A GB360254 A GB 360254A GB 775564 A GB775564 A GB 775564A
Authority
GB
United Kingdom
Prior art keywords
feb
instruments
relating
tone
transistor
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
GB360254A
Inventor
Lyndall Crossthwaite Pocock
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
Priority to GB360254A priority Critical patent/GB775564A/en
Publication of GB775564A publication Critical patent/GB775564A/en
Expired legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04M—TELEPHONIC COMMUNICATION
    • H04M1/00—Substation equipment, e.g. for use by subscribers
    • H04M1/58—Anti-side-tone circuits

Landscapes

  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Cable Transmission Systems, Equalization Of Radio And Reduction Of Echo (AREA)

Abstract

775,564. Substation anti-side-tone circuits. STANDARD TELEPHONES & CABLES, Ltd. Feb. 4, 1955 [Feb. 8, 1954], No. 3602/54. Class 40 (4). The usual induction coil is omitted, side-tone being minimized by means of a Wheatstone bridge arrangement as shown. The resulting transmission losses are offset by the use of a transistor TR to amplify the output of the transmitter TX. In a modification, Fig. 6 (not shown), a sound-powered transmitter may be used with two stages of transistor amplification in cascade. Compensation for variations in line impedance may be effected by means of a network containing one or more non-linear resistance devices, Figs. 3, 4, 5, 7, 8 (not shown). Specification 694,021 is referred to.
GB360254A 1954-02-08 1954-02-08 Improvements in or relating to telephone subscribers' instruments Expired GB775564A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB360254A GB775564A (en) 1954-02-08 1954-02-08 Improvements in or relating to telephone subscribers' instruments

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB360254A GB775564A (en) 1954-02-08 1954-02-08 Improvements in or relating to telephone subscribers' instruments

Publications (1)

Publication Number Publication Date
GB775564A true GB775564A (en) 1957-05-29

Family

ID=9761424

Family Applications (1)

Application Number Title Priority Date Filing Date
GB360254A Expired GB775564A (en) 1954-02-08 1954-02-08 Improvements in or relating to telephone subscribers' instruments

Country Status (1)

Country Link
GB (1) GB775564A (en)

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