GB683841A - Improvements relating to radio receivers - Google Patents

Improvements relating to radio receivers

Info

Publication number
GB683841A
GB683841A GB1862750A GB1862750A GB683841A GB 683841 A GB683841 A GB 683841A GB 1862750 A GB1862750 A GB 1862750A GB 1862750 A GB1862750 A GB 1862750A GB 683841 A GB683841 A GB 683841A
Authority
GB
United Kingdom
Prior art keywords
frequency
periodic
fading
gain control
rapid
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
GB1862750A
Inventor
Harry Norman Gant
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.)
EMI Ltd
Electrical and Musical Industries Ltd
Original Assignee
EMI Ltd
Electrical and Musical Industries 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 EMI Ltd, Electrical and Musical Industries Ltd filed Critical EMI Ltd
Priority to GB1862750A priority Critical patent/GB683841A/en
Publication of GB683841A publication Critical patent/GB683841A/en
Expired legal-status Critical Current

Links

Classifications

    • 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
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03G—CONTROL OF AMPLIFICATION
    • H03G11/00—Limiting amplitude; Limiting rate of change of amplitude ; Clipping in general
    • H03G11/004—Limiting amplitude; Limiting rate of change of amplitude ; Clipping in general using discharge tubes
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03G—CONTROL OF AMPLIFICATION
    • H03G11/00—Limiting amplitude; Limiting rate of change of amplitude ; Clipping in general
    • H03G11/06—Limiters of angle-modulated signals; such limiters combined with discriminators

Landscapes

  • Mobile Radio Communication Systems (AREA)
  • Noise Elimination (AREA)
  • Circuits Of Receivers In General (AREA)

Abstract

683,841. Frequency modulation; automatic gain control. ELECTRIC & MUSICAL INDUSTRIES, Ltd. June 29, 1951 [July 26, 1950], No. 18627/50. Class 40 (v). Rapid fading in F.M. receivers, such as is observed in car receivers moving quickly through a built-up area, is liable to cause a " fluttering " of the received signal owing to the action of the automatic gain control giving periodic bursts of enhanced noise every time the car passes through a position of low field strength. The invention provides means for reducing this effect by arranging that the A.G.C. circuit does not function for periodic fading of the order of frequency (e.g. 10-60 c/s.) at which this phenomenon is observed. As shown, the F.M. receiver comprises a frequency-changing stage 1 and I.F. amplifiers 6, 7 feeding a gridcurrent pentode limiter 11, the output of which passes to a frequency-discriminating detector 14, amplifier 15 and loud-speaker 16. Gaincontrol voltage is taken from a tapping on the grid-cathode resistor 12, 13 of the limiter 11 and is fed back through a low-pass filter 18, 19 to the grid of the I.F. valve 6. The time constant of the filter is chosen so that the gain control, whilst effective for slow changes of field strength, is ineffective at the frequency of the periodic rapid fading, and at higher frequencies. In practice this time constant may be one-fifth of a second. The system may be used on a stationary receiver for receiving transmissions from a mobile transmitter, or in other circumstances in which rapid periodic fading may occur.
GB1862750A 1950-07-26 1950-07-26 Improvements relating to radio receivers Expired GB683841A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB1862750A GB683841A (en) 1950-07-26 1950-07-26 Improvements relating to radio receivers

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB1862750A GB683841A (en) 1950-07-26 1950-07-26 Improvements relating to radio receivers

Publications (1)

Publication Number Publication Date
GB683841A true GB683841A (en) 1952-12-03

Family

ID=10115706

Family Applications (1)

Application Number Title Priority Date Filing Date
GB1862750A Expired GB683841A (en) 1950-07-26 1950-07-26 Improvements relating to radio receivers

Country Status (1)

Country Link
GB (1) GB683841A (en)

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