GB544364A - Telephone circuits - Google Patents

Telephone circuits

Info

Publication number
GB544364A
GB544364A GB12490/41A GB1249041A GB544364A GB 544364 A GB544364 A GB 544364A GB 12490/41 A GB12490/41 A GB 12490/41A GB 1249041 A GB1249041 A GB 1249041A GB 544364 A GB544364 A GB 544364A
Authority
GB
United Kingdom
Prior art keywords
amplitude
filter
transmitter
receiver
circuits
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
GB12490/41A
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 US278411A external-priority patent/US2287998A/en
Application filed by Standard Telephone and Cables PLC filed Critical Standard Telephone and Cables PLC
Publication of GB544364A publication Critical patent/GB544364A/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

544,364. Substation circuits. STANDARD TELEPHONES & CABLES, Ltd. May 17, 1940, No. 12490/41. Convention date, June 10, 1939. Divided out of 542,643. [Class 40 (iv)] [Also in Group XL] For avoiding side-tone and room noise effects, a telephone set is provided with one or more amplitude-filters in the form of bridge circuits which are balanced for all levels above a given limit or for all levels below a given limit. In circuits for eliminating room noise, a high-pass amplitude filter R2, V, Rp is inserted between the transmitter T and the receiver R, Figs. 9, 10 (not shown) and Fig. 11. 'In arrangements for eliminating side-tone, an amplitude-filter of the low-pass type is associated with the receiver R and disables it when the transmitter T is spoken into, Figs. 12 to 14 (not shown) and Fig. 15. In other arrangements, Fig. 16 (not shown) and Fig. 8, a high-pass amplitude-filter is associated with the transmitter T and a lowpass amplitude-filter with the receiver R to give both advantages.
GB12490/41A 1939-06-10 1940-05-17 Telephone circuits Expired GB544364A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US278411A US2287998A (en) 1939-06-10 1939-06-10 Telephone circuit
US434372A US2332643A (en) 1939-06-10 1942-03-12 Telephone set circuit

Publications (1)

Publication Number Publication Date
GB544364A true GB544364A (en) 1942-04-09

Family

ID=26959081

Family Applications (2)

Application Number Title Priority Date Filing Date
GB8841/40A Expired GB542643A (en) 1939-06-10 1940-05-17 Telephone set circuits
GB12490/41A Expired GB544364A (en) 1939-06-10 1940-05-17 Telephone circuits

Family Applications Before (1)

Application Number Title Priority Date Filing Date
GB8841/40A Expired GB542643A (en) 1939-06-10 1940-05-17 Telephone set circuits

Country Status (5)

Country Link
US (1) US2332643A (en)
BE (1) BE439637A (en)
CH (1) CH222392A (en)
FR (1) FR866096A (en)
GB (2) GB542643A (en)

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2559778A (en) * 1948-04-02 1951-07-10 Modern Telephone Corp Intercommunication telephone system
DE886766C (en) * 1951-03-03 1953-08-17 Normalzeit G M B H Device to prevent unauthorized eavesdropping on telephone conversations
US2764731A (en) * 1953-05-06 1956-09-25 Bell Telephone Labor Inc Thermistor network
DE1016760B (en) * 1953-07-07 1957-10-03 Deutsche Bundespost Circuit arrangement for volume control in telephone subscriber connection lines
NL100978C (en) * 1956-03-29
US3143700A (en) * 1960-08-12 1964-08-04 Computing Devices Canada Resistance networks for stabilizing phase shift in resolvers and the like

Also Published As

Publication number Publication date
BE439637A (en)
FR866096A (en) 1941-06-16
US2332643A (en) 1943-10-26
GB542643A (en) 1942-01-21
CH222392A (en) 1942-07-15

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