GB407405A - Improvements in electro-mechanical devices such as instruments for recording, reproducing, or transmitting sound - Google Patents

Improvements in electro-mechanical devices such as instruments for recording, reproducing, or transmitting sound

Info

Publication number
GB407405A
GB407405A GB2636732A GB2636732A GB407405A GB 407405 A GB407405 A GB 407405A GB 2636732 A GB2636732 A GB 2636732A GB 2636732 A GB2636732 A GB 2636732A GB 407405 A GB407405 A GB 407405A
Authority
GB
United Kingdom
Prior art keywords
loud
speaker
resistance
capacity
instruments
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
GB2636732A
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.)
RUPERT WOODVILLI HARDISTY
STC PLC
Original Assignee
RUPERT WOODVILLI HARDISTY
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 RUPERT WOODVILLI HARDISTY, Standard Telephone and Cables PLC filed Critical RUPERT WOODVILLI HARDISTY
Priority to GB2636732A priority Critical patent/GB407405A/en
Publication of GB407405A publication Critical patent/GB407405A/en
Expired legal-status Critical Current

Links

Classifications

    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04HBROADCAST COMMUNICATION
    • H04H20/00Arrangements for broadcast or for distribution combined with broadcast
    • H04H20/65Arrangements characterised by transmission systems for broadcast
    • H04H20/76Wired systems
    • H04H20/82Wired systems using signals not modulated onto a carrier
    • H04H20/83Wired systems using signals not modulated onto a carrier not sharing the network with any other service

Abstract

407,405. Circuits for magnetic instruments. STANDARD TELEPHONES & CABLES, Ltd., SANDEMAN, E. K., ATHERTON, J. F., and HARDISTY, R. W., Connaught House, Aldwych, London. Sept. 22, 1932, No. 26367. [Class 40 (iv).] A loud-speaker, moving-coil microphone, gramophone recorder or reproducer or the like having two or more inductive windings is given a substantially constant impedance over the voice-frequency range by associating therewith resistance and capacity to form a constant impedance lattice network. The resistance and capacity may be associated with a transformer connected to the loud-speaker &c. In the form shown in Fig. 1, the windings W1, W2 are associated with equal condensers C1, C2 to form a network which is terminated by a resistance R, the values being determined by R = #L/2C where L is the total inductance and C the capacity of each condenser. The inductance may be taken as that corresponding to the knee B in the reactance-angular frequency curve, shown in Fig. 3, of the inductive windings, R being made equal to the impedance of the circuit which works into the loud-speaker &c., or the most suitable corresponding values of R and C may be determined experimentally. The network may be formed by associating the resistance R and condensers C1, C2 with a split-primary transformer as shown in Fig. 2 particularly when the loud-speaker &c. has a single winding. The invention is useful for coupling loud-speakers to pentodes, or where a number of moving iron instruments are connected in parallel so that normally the total impedance at low frequences would be extremely small.
GB2636732A 1932-09-22 1932-09-22 Improvements in electro-mechanical devices such as instruments for recording, reproducing, or transmitting sound Expired GB407405A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB2636732A GB407405A (en) 1932-09-22 1932-09-22 Improvements in electro-mechanical devices such as instruments for recording, reproducing, or transmitting sound

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB2636732A GB407405A (en) 1932-09-22 1932-09-22 Improvements in electro-mechanical devices such as instruments for recording, reproducing, or transmitting sound

Publications (1)

Publication Number Publication Date
GB407405A true GB407405A (en) 1934-03-22

Family

ID=10242543

Family Applications (1)

Application Number Title Priority Date Filing Date
GB2636732A Expired GB407405A (en) 1932-09-22 1932-09-22 Improvements in electro-mechanical devices such as instruments for recording, reproducing, or transmitting sound

Country Status (1)

Country Link
GB (1) GB407405A (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE902016C (en) * 1938-04-15 1954-01-18 Western Electric Co Amplifier with negative feedback
US3061676A (en) * 1959-02-05 1962-10-30 Electro Voice Sound reproducing device
EP1696699A2 (en) * 2005-02-25 2006-08-30 Pantech&Curitel Communications, Inc. IC chip type hearing aid module for mobile communication terminal

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE902016C (en) * 1938-04-15 1954-01-18 Western Electric Co Amplifier with negative feedback
US3061676A (en) * 1959-02-05 1962-10-30 Electro Voice Sound reproducing device
EP1696699A2 (en) * 2005-02-25 2006-08-30 Pantech&Curitel Communications, Inc. IC chip type hearing aid module for mobile communication terminal
EP1696699A3 (en) * 2005-02-25 2009-11-04 Pantech&Curitel Communications, Inc. IC chip type hearing aid module for mobile communication terminal
US7657046B2 (en) 2005-02-25 2010-02-02 Pantech & Curitel Communications, Inc. IC chip type hearing aid module for mobile communication terminal
US7974426B2 (en) 2005-02-25 2011-07-05 Pantech & Curitel Communications, Inc. IC chip type hearing aid module for mobile communication terminal

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