GB735506A - Improvements in and relating to variable impedance devices - Google Patents

Improvements in and relating to variable impedance devices

Info

Publication number
GB735506A
GB735506A GB3152550A GB3152550A GB735506A GB 735506 A GB735506 A GB 735506A GB 3152550 A GB3152550 A GB 3152550A GB 3152550 A GB3152550 A GB 3152550A GB 735506 A GB735506 A GB 735506A
Authority
GB
United Kingdom
Prior art keywords
circuit
valve
oscillator
rectifiers
rectifier
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
GB3152550A
Inventor
Dennis Godson Holloway
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.)
British Telecommunications PLC
British Telecommunications Research Ltd
Original Assignee
British Telecommunications PLC
British Telecommunications Research Ltd
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 British Telecommunications PLC, British Telecommunications Research Ltd filed Critical British Telecommunications PLC
Priority to GB3152550A priority Critical patent/GB735506A/en
Publication of GB735506A publication Critical patent/GB735506A/en
Expired legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03C—MODULATION
    • H03C3/00—Angle modulation
    • H03C3/02—Details
    • H03C3/09—Modifications of modulator for regulating the mean frequency
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03J—TUNING RESONANT CIRCUITS; SELECTING RESONANT CIRCUITS
    • H03J7/00—Automatic frequency control; Automatic scanning over a band of frequencies
    • H03J7/02—Automatic frequency control
    • H03J7/04—Automatic frequency control where the frequency control is accomplished by varying the electrical characteristics of a non-mechanically adjustable element or where the nature of the frequency controlling element is not significant
    • H03J7/042—Automatic frequency control where the frequency control is accomplished by varying the electrical characteristics of a non-mechanically adjustable element or where the nature of the frequency controlling element is not significant with reactance tube
    • 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
    • H04B1/38—Transceivers, i.e. devices in which transmitter and receiver form a structural unit and in which at least one part is used for functions of transmitting and receiving
    • H04B1/40—Circuits

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Electrostatic, Electromagnetic, Magneto- Strictive, And Variable-Resistance Transducers (AREA)
  • Channel Selection Circuits, Automatic Tuning Circuits (AREA)
  • Superheterodyne Receivers (AREA)

Abstract

735,506. Impedance networks. BRITISH TELECOMMUNICATIONS RESEARCH, Ltd. Dec. 17, 1951 [Dec. 28, 1950], No. 31525/50. Class 40 (8). [Also in Group XL (c)] A variable impedance comprises a capacitor and a rectifier connected in series between two terminals, and a further rectifier and a source of variable bias voltage is connected across the first rectifier, the two rectifiers being in reversed parallel connection and the source of bias voltage is a capacitor shunted by a leakage resistance connected across both the rectifiers, the bias thus varying according to the current circulating in the impedance circuit. In Fig. 7, the arrangement is shown applied to the frequency modulation of an oscillator. A control voltage is applied at terminal T4 of valve V2 and the current in resistance R is thus varied, this resistance supplying the bias for a circuit (capacitors C1 and C2 and rectifiers D1 and D2) according to the invention. This circuit is linked with a resonant circuit LS in the output connection of an oscillator valve V1. In the receiving and transmitting set shown in Fig. 8, current from a microphone H with its associated valve V2 modulates the output from oscillator valve V1 through a variable impedance circuit C2 as in the previous construction. The receiver circuit comprises a local oscillator O, a mixer M, amplifier E, discriminator F, valve B and earphones G. Specification 667,065, [Group XL (c)], is referred to.
GB3152550A 1950-12-28 1950-12-28 Improvements in and relating to variable impedance devices Expired GB735506A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB3152550A GB735506A (en) 1950-12-28 1950-12-28 Improvements in and relating to variable impedance devices

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB3152550A GB735506A (en) 1950-12-28 1950-12-28 Improvements in and relating to variable impedance devices

Publications (1)

Publication Number Publication Date
GB735506A true GB735506A (en) 1955-08-24

Family

ID=10324392

Family Applications (1)

Application Number Title Priority Date Filing Date
GB3152550A Expired GB735506A (en) 1950-12-28 1950-12-28 Improvements in and relating to variable impedance devices

Country Status (1)

Country Link
GB (1) GB735506A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1171029B (en) * 1961-04-05 1964-05-27 Siemens Ag Circuit for frequency readjustment of tunable oscillators

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1171029B (en) * 1961-04-05 1964-05-27 Siemens Ag Circuit for frequency readjustment of tunable oscillators

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