GB726240A - Improvements in and relating to high frequency communication systems - Google Patents

Improvements in and relating to high frequency communication systems

Info

Publication number
GB726240A
GB726240A GB7913/53A GB791353A GB726240A GB 726240 A GB726240 A GB 726240A GB 7913/53 A GB7913/53 A GB 7913/53A GB 791353 A GB791353 A GB 791353A GB 726240 A GB726240 A GB 726240A
Authority
GB
United Kingdom
Prior art keywords
valve
tube
carrier
resistance
received
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
GB7913/53A
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.)
General Electric Co
Original Assignee
General Electric Co
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 General Electric Co filed Critical General Electric Co
Publication of GB726240A publication Critical patent/GB726240A/en
Expired legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W88/00—Devices specially adapted for wireless communication networks, e.g. terminals, base stations or access point devices
    • H04W88/02—Terminal devices
    • H04W88/022—Selective call receivers
    • H04W88/025—Selective call decoders
    • H04W88/027—Selective call decoders using frequency address codes
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03G—CONTROL OF AMPLIFICATION
    • H03G3/00—Gain control in amplifiers or frequency changers
    • H03G3/20—Automatic control
    • H03G3/22—Automatic control in amplifiers having discharge tubes
    • H03G3/26—Muting amplifier when no signal is present or when only weak signals are present, or caused by the presence of noise, e.g. squelch systems
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • H04B1/06—Receivers
    • H04B1/16—Circuits
    • H04B1/26—Circuits for superheterodyne receivers

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Alarm Systems (AREA)
  • Fire-Detection Mechanisms (AREA)
  • Mobile Radio Communication Systems (AREA)

Abstract

726,240. Radio signalling; receiving systems. GENERAL ELECTRIC CO. March 23, 1953 (March 25, 1952], No. 7913/53. Class 40 (5). In a selective calling system a receiver has a gaseous discharge tube 49 to the anode of which H.T. is applied by the received carrier and to the grid of which a particular call tone of short duration, e.g. one half second, when transmitted is applied from a selective amplifier 59 to fire the tube. This short circuits one resistance 46 of a resistance bridge so that the voltage across the terminals 54, 53 alters from zero to a value cutting off the valve 71 and therefore opening a normally blocked gate valve 72 to which the demodulated incoming signal is applied. The signal therefore is received so long as the carrier is transmitted but is cut off when the carrier ceases, the gaseous tube 49 then reverting to its unenergized condition. The H.T. may be derived from the cathode of a series-connected gate valve 39 operated from an amplifier valve 29 and cathode follower 24, operated by the negative bias voltage which builds up on the grid of a limiter valve 4 of a frequency modulation receiver when a carrier is received. In a modification the valve 39 is omitted, the resistance 36 being connected direct to the anode of the gaseous tube, and the tube cathode through the resistance 45 to a H.T. voltage-divider network.
GB7913/53A 1952-03-25 1953-03-23 Improvements in and relating to high frequency communication systems Expired GB726240A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US726240XA 1952-03-25 1952-03-25
US278420A US2647993A (en) 1952-03-25 1952-03-25 High-frequency communication system

Publications (1)

Publication Number Publication Date
GB726240A true GB726240A (en) 1955-03-16

Family

ID=26753560

Family Applications (1)

Application Number Title Priority Date Filing Date
GB7913/53A Expired GB726240A (en) 1952-03-25 1953-03-23 Improvements in and relating to high frequency communication systems

Country Status (2)

Country Link
US (1) US2647993A (en)
GB (1) GB726240A (en)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2770721A (en) * 1952-05-03 1956-11-13 Motorola Inc Squelch circuit
US2800582A (en) * 1953-06-30 1957-07-23 Westinghouse Air Brake Co Noise suppression and limiter circuits
US2900498A (en) * 1955-08-02 1959-08-18 Gen Railway Signal Co Fail-safe protection for code communication control systems
US3599099A (en) * 1967-02-15 1971-08-10 Nippon Broadcasting System System for transferring audio system output to predetermined broadcast signal

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR953214A (en) * 1946-09-27
US2591937A (en) * 1947-05-01 1952-04-08 Automatic Elect Lab Selective calling system
US2610293A (en) * 1948-02-14 1952-09-09 Rca Corp Signal responsive receiver

Also Published As

Publication number Publication date
US2647993A (en) 1953-08-04

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