GB556319A - Improvements relating to radio receivers - Google Patents

Improvements relating to radio receivers

Info

Publication number
GB556319A
GB556319A GB406442A GB406442A GB556319A GB 556319 A GB556319 A GB 556319A GB 406442 A GB406442 A GB 406442A GB 406442 A GB406442 A GB 406442A GB 556319 A GB556319 A GB 556319A
Authority
GB
United Kingdom
Prior art keywords
aerial
alarm
wavelength
receiver
circuit
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
GB406442A
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
Publication of GB556319A publication Critical patent/GB556319A/en
Expired legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L15/00—Apparatus or local circuits for transmitting or receiving dot-and-dash codes, e.g. Morse code
    • H04L15/24—Apparatus or circuits at the receiving end
    • H04L15/26—Apparatus or circuits at the receiving end operating only on reception of predetermined code signals, e.g. distress signals, party-line call signals
    • 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
    • H04B1/02—Transmitters
    • H04B1/03—Constructional details, e.g. casings, housings
    • H04B1/034—Portable transmitters

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Monitoring And Testing Of Transmission In General (AREA)
  • Circuits Of Receivers In General (AREA)

Abstract

556,319. Wireless signalling. STANDARD TELEPHONES & CABLES, Ltd., and HOLLAND, J. D. March 27, 1942, No. 4064. [Class 40 (v)] A testing arrangement for a radio alarm system comprises an aerial, a radio receiver adapted to be tuned to the alarm wavelength, means for switching the aerial from the receiver to a variable inductance to form therewith a circuit resonant at the alarm wavelength, and means to excite the resonant circuit to cause it to generate waves adapted to be detected by the receiver. An aerial A is connected by a switch S in the ON position to a receiver RR tuned to the alarm wavelength. A test circuit comprises a variable inductance L1 which, with the inherent capacity C of the aerial, forms a circuit resonant at the alarm wavelength. A fixed inductance L2 is coupled to L1 and is arranged in series with a resistance R and the make and break contacts of a buzzer B. Closure of a key K energizes a relay RY to connect the aerial to the inductance Ll and also energizes the buzzer B so as to excite the circuit L1C through L2 and radiate a signal from the aerial at the alarm wavelength. Reception of this signal by the receiver RR indicates that the aerial is operative and is connected by switch S to the receiver which is tuned to the alarm wavelength. A low pass filter F prevents radiation of buzzer modulation from the leads.
GB406442A 1942-10-30 1942-03-27 Improvements relating to radio receivers Expired GB556319A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB1526442A GB561091A (en) 1942-10-30 1942-10-30 Improvements relating to radio receivers

Publications (1)

Publication Number Publication Date
GB556319A true GB556319A (en) 1943-09-29

Family

ID=10055970

Family Applications (2)

Application Number Title Priority Date Filing Date
GB406442A Expired GB556319A (en) 1942-10-30 1942-03-27 Improvements relating to radio receivers
GB1526442A Expired GB561091A (en) 1942-10-30 1942-10-30 Improvements relating to radio receivers

Family Applications After (1)

Application Number Title Priority Date Filing Date
GB1526442A Expired GB561091A (en) 1942-10-30 1942-10-30 Improvements relating to radio receivers

Country Status (1)

Country Link
GB (2) GB556319A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE964251C (en) * 1955-02-10 1957-05-23 Hagenuk Neufeldt Kuhnke Gmbh Method and device for testing receiving systems that automatically indicate the reception of certain high-frequency signals

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE964251C (en) * 1955-02-10 1957-05-23 Hagenuk Neufeldt Kuhnke Gmbh Method and device for testing receiving systems that automatically indicate the reception of certain high-frequency signals

Also Published As

Publication number Publication date
GB561091A (en) 1944-05-04

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