GB540179A - Improvements in or relating to mechanical amplifiers for telephone subsets - Google Patents

Improvements in or relating to mechanical amplifiers for telephone subsets

Info

Publication number
GB540179A
GB540179A GB6174/40A GB617440A GB540179A GB 540179 A GB540179 A GB 540179A GB 6174/40 A GB6174/40 A GB 6174/40A GB 617440 A GB617440 A GB 617440A GB 540179 A GB540179 A GB 540179A
Authority
GB
United Kingdom
Prior art keywords
amplifier
microphone
connections
transmitter
fed
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
GB6174/40A
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 GB6174/40A priority Critical patent/GB540179A/en
Priority to US383401A priority patent/US2318681A/en
Publication of GB540179A publication Critical patent/GB540179A/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
    • H04M1/60—Substation equipment, e.g. for use by subscribers including speech amplifiers
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F13/00—Amplifiers using amplifying element consisting of two mechanically- or acoustically-coupled transducers, e.g. telephone-microphone amplifier

Landscapes

  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Power Engineering (AREA)
  • Amplifiers (AREA)

Abstract

540,179. Substation apparatus. STANDARD TELEPHONES & CABLES, Ltd., and FAIRLEY, F. April 5, 1940, No. 6174. [Class 40 (iv)] A receiving amplifier for a substation set comprises a magneto-microphonic amplifier the carbon granule microphone of which is fed from the same battery as the transmitter of the set. The amplifier is particularly applicable to military field telephones in which the instruments proper are connected to the remainder of the set by a cord and 4-pin plug and socket and is provided with corresponding plug and socket connections. The amplifier comprises an input matching transformer T1, magnetic receiver AR mechanically coupled to a microphone AT and an output matching transformer T2, and the connections between the 4-pin plug on the input side and the 4 sockets on the output side include direct connections for the transmitter T of the set which is fed from local battery B over switch hook contact S, feed for the amplifier microphone being taken from these direct leads over a variable resistance P which may be used for volume control. A known anti-side-tone circuit I, N is used. Residual side-tone which would be increased by amplification is minimized by arranging that the side-tones over the two paths T, I, T1, T2, R and T, P, T2, R are in opposition. The microphone AR may be sealed in a chamber containing dry air or inert gas such as hydrogen.
GB6174/40A 1940-04-05 1940-04-05 Improvements in or relating to mechanical amplifiers for telephone subsets Expired GB540179A (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
GB6174/40A GB540179A (en) 1940-04-05 1940-04-05 Improvements in or relating to mechanical amplifiers for telephone subsets
US383401A US2318681A (en) 1940-04-05 1941-03-14 Telephone set

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB6174/40A GB540179A (en) 1940-04-05 1940-04-05 Improvements in or relating to mechanical amplifiers for telephone subsets

Publications (1)

Publication Number Publication Date
GB540179A true GB540179A (en) 1941-10-08

Family

ID=9809765

Family Applications (1)

Application Number Title Priority Date Filing Date
GB6174/40A Expired GB540179A (en) 1940-04-05 1940-04-05 Improvements in or relating to mechanical amplifiers for telephone subsets

Country Status (2)

Country Link
US (1) US2318681A (en)
GB (1) GB540179A (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE971783C (en) * 1952-07-25 1959-03-26 Standard Elek K Lorenz Ag Arrangement for telephones with an amplifier device which can be connected upstream of the earpiece and is arranged in the handset

Also Published As

Publication number Publication date
US2318681A (en) 1943-05-11

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