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GB514520A - Improvements in or relating to alternating current signalling systems - Google Patents

Improvements in or relating to alternating current signalling systems

Info

Publication number
GB514520A
GB514520A GB13664/38A GB1366438A GB514520A GB 514520 A GB514520 A GB 514520A GB 13664/38 A GB13664/38 A GB 13664/38A GB 1366438 A GB1366438 A GB 1366438A GB 514520 A GB514520 A GB 514520A
Authority
GB
United Kingdom
Prior art keywords
frequency
signals
impulses
rectifier
condenser
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
GB13664/38A
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.)
Individual
Original Assignee
Individual
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 to BE434099D priority Critical patent/BE434099A/xx
Priority to NL93258D priority patent/NL93258C/xx
Priority to NL64018D priority patent/NL64018C/xx
Application filed by Individual filed Critical Individual
Priority to GB13664/38A priority patent/GB514520A/en
Priority to US269524A priority patent/US2282129A/en
Publication of GB514520A publication Critical patent/GB514520A/en
Expired legal-status Critical Current

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07D—HETEROCYCLIC COMPOUNDS
    • C07D213/00—Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members
    • C07D213/02—Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members having three double bonds between ring members or between ring members and non-ring members
    • C07D213/04—Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members having three double bonds between ring members or between ring members and non-ring members having no bond between the ring nitrogen atom and a non-ring member or having only hydrogen or carbon atoms directly attached to the ring nitrogen atom
    • C07D213/60—Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members having three double bonds between ring members or between ring members and non-ring members having no bond between the ring nitrogen atom and a non-ring member or having only hydrogen or carbon atoms directly attached to the ring nitrogen atom with hetero atoms or with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, e.g. ester or nitrile radicals, directly attached to ring carbon atoms
    • C07D213/78—Carbon atoms having three bonds to hetero atoms, with at the most one bond to halogen, e.g. ester or nitrile radicals
    • C07D213/86—Hydrazides; Thio or imino analogues thereof
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/02—Amplitude-modulated carrier systems, e.g. using on-off keying; Single sideband or vestigial sideband modulation
    • H04L27/06—Demodulator circuits; Receiver circuits
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04Q—SELECTING
    • H04Q1/00—Details of selecting apparatus or arrangements
    • H04Q1/18—Electrical details
    • H04Q1/30—Signalling arrangements; Manipulation of signalling currents
    • H04Q1/44—Signalling arrangements; Manipulation of signalling currents using alternate current
    • H04Q1/444—Signalling arrangements; Manipulation of signalling currents using alternate current with voice-band signalling frequencies
    • H04Q1/446—Signalling arrangements; Manipulation of signalling currents using alternate current with voice-band signalling frequencies using one signalling frequency
    • H04Q1/4465—Signalling arrangements; Manipulation of signalling currents using alternate current with voice-band signalling frequencies using one signalling frequency the same frequency being used for all signalling information, e.g. A.C. nr.9 system

Landscapes

  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Electrotherapy Devices (AREA)
  • Interface Circuits In Exchanges (AREA)
  • Telephonic Communication Services (AREA)

Abstract

514,520. Automatic exchange systems. HADFIELD, B. M. May 7, 1938, No. 13664. [Class 40 (iv)] [Also in Group XL] In a system in which signals are sent in the form of impulses of alternating current which are translated into direct current impulses at the receiving end, the signals pass through a frequency multiplying circuit before translation. In the arrangement shown, which is particularly suitable for single or multi-channel voice frequency telegraph systems or for the reception of 750 cycle dialling impulses in.telephony, the signals pass through two frequency doublers in cascade, the first comprising a pair of valves V1 and the second a full-wave rectifier RD, to a transformer T3 tuned by a condenser C3 to the quadrupled frequency, and thence to a valve V2 which controls a rectifying arrangement of the kind described in Specification 505,500, [Group XL]. The direct current component derived from the rectifier RD is applied across a resistance R and by means of a condenser C and rectifier R1, R2 provides a negative bias which builds up quickly but decays slowly to render the valve V2 inoperative until the signals in the tuned circuit T3, C3, reach one-half the peak voltage. Since all incoming frequencies contribute to the biassing effect, the arrangement automatically prevents operation by speech containing a proportion of the signalling- frequency.
GB13664/38A 1938-05-07 1938-05-07 Improvements in or relating to alternating current signalling systems Expired GB514520A (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
BE434099D BE434099A (en) 1938-05-07
NL93258D NL93258C (en) 1938-05-07
NL64018D NL64018C (en) 1938-05-07
GB13664/38A GB514520A (en) 1938-05-07 1938-05-07 Improvements in or relating to alternating current signalling systems
US269524A US2282129A (en) 1938-05-07 1939-04-22 Alternating current signaling system

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB13664/38A GB514520A (en) 1938-05-07 1938-05-07 Improvements in or relating to alternating current signalling systems

Publications (1)

Publication Number Publication Date
GB514520A true GB514520A (en) 1939-11-10

Family

ID=10027155

Family Applications (1)

Application Number Title Priority Date Filing Date
GB13664/38A Expired GB514520A (en) 1938-05-07 1938-05-07 Improvements in or relating to alternating current signalling systems

Country Status (4)

Country Link
US (1) US2282129A (en)
BE (1) BE434099A (en)
GB (1) GB514520A (en)
NL (2) NL93258C (en)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB654639A (en) * 1947-02-07 1951-06-27 Standard Telephones Cables Ltd Improvements in or relating to electric signalling systems
BE510949A (en) * 1951-04-27
JPS5340824A (en) * 1976-09-27 1978-04-13 Hitachi Ltd Combining circuit

Also Published As

Publication number Publication date
NL64018C (en)
BE434099A (en)
US2282129A (en) 1942-05-05
NL93258C (en)

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