GB594769A - Improvements in and relating to frequency modulation receivers - Google Patents

Improvements in and relating to frequency modulation receivers

Info

Publication number
GB594769A
GB594769A GB7770/44A GB777044A GB594769A GB 594769 A GB594769 A GB 594769A GB 7770/44 A GB7770/44 A GB 7770/44A GB 777044 A GB777044 A GB 777044A GB 594769 A GB594769 A GB 594769A
Authority
GB
United Kingdom
Prior art keywords
valve
signal
resistances
load
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
GB7770/44A
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 Thomson Houston Co Ltd
Original Assignee
British Thomson Houston Co 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 Thomson Houston Co Ltd filed Critical British Thomson Houston Co Ltd
Publication of GB594769A publication Critical patent/GB594769A/en
Expired legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03D—DEMODULATION OR TRANSFERENCE OF MODULATION FROM ONE CARRIER TO ANOTHER
    • H03D3/00—Demodulation of angle-, frequency- or phase- modulated oscillations
    • H03D3/02—Demodulation of angle-, frequency- or phase- modulated oscillations by detecting phase difference between two signals obtained from input signal
    • H03D3/06—Demodulation of angle-, frequency- or phase- modulated oscillations by detecting phase difference between two signals obtained from input signal by combining signals additively or in product demodulators
    • H03D3/08—Demodulation of angle-, frequency- or phase- modulated oscillations by detecting phase difference between two signals obtained from input signal by combining signals additively or in product demodulators by means of diodes, e.g. Foster-Seeley discriminator
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03D—DEMODULATION OR TRANSFERENCE OF MODULATION FROM ONE CARRIER TO ANOTHER
    • H03D3/00—Demodulation of angle-, frequency- or phase- modulated oscillations
    • H03D3/02—Demodulation of angle-, frequency- or phase- modulated oscillations by detecting phase difference between two signals obtained from input signal
    • H03D3/06—Demodulation of angle-, frequency- or phase- modulated oscillations by detecting phase difference between two signals obtained from input signal by combining signals additively or in product demodulators
    • H03D3/08—Demodulation of angle-, frequency- or phase- modulated oscillations by detecting phase difference between two signals obtained from input signal by combining signals additively or in product demodulators by means of diodes, e.g. Foster-Seeley discriminator
    • H03D3/10—Demodulation of angle-, frequency- or phase- modulated oscillations by detecting phase difference between two signals obtained from input signal by combining signals additively or in product demodulators by means of diodes, e.g. Foster-Seeley discriminator in which the diodes are simultaneously conducting during the same half period of the signal, e.g. radio detector
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03G—CONTROL OF AMPLIFICATION
    • H03G3/00—Gain control in amplifiers or frequency changers without distortion of the input signal
    • 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
    • H03G3/28—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 in frequency-modulation receivers ; in angle-modulation receivers

Abstract

594,769. Frequency modulation. BRITISH THOMSON-HOUSTON CO., Ltd. April 26, 1944, No. 7770. Convention date, April 27, 1943. [Class 40 (v)] In order to provide steady increase and decrease of signal strength, and to reduce distortion, when tuning a frequencymodulation receiver through a desired station, a balanced discriminator is employed and each rectifier feeds the receiving instrument through a separate channel. These channels each include a valve, and bias potentials derived from the rectifier circuits operate on the valves to diminish the signal response from that rectifier which, owing to mistuning, tends to take the greater load. As shown, a discriminator network 11, 14, 15 of the phasing type feeds oppositely-poled diodes 20, 29, each of which is connected to a divided load resistance 22, 23 and 26, 27, the division points being earthed. The signal is fed from a tap 40 on resistance 22 through a condenser 42 to the grid of a valve 44 and from a tap 41 to the grid of a valve 45. The valve anodes are connected in parallel to the signal output circuit 60 and as the alternating signal voltages are in phase, their effects add in the output circuit. A bias voltage for the valve 44 is provided from the mid-point of resistances 55, 56 connected between the unearthed ends of the load resistances 23, 26 ; and bias voltage for the valve 45 from similar resistances 53, 54 connected between the unearthed ends of load resistances 22, 27. In this way, the channel which, owing to mistuning, would otherwise be operating on the hump of its discriminator curve E or E2, Fig. 3, is reduced in effectiveness, while the other channel is improved. The coupling afforded by the condenser-shunted resistance 48 in the common cathode lead of the valves 44, 45 enhances this reciprocal action. In a modification (Fig. 5, not shown), the triodes 44, 45 are replaced by oppositely-poled diodes, the signal and bias voltages being applied to their anodes and cathodes.
GB7770/44A 1943-04-27 1944-04-26 Improvements in and relating to frequency modulation receivers Expired GB594769A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US484718A US2362806A (en) 1943-04-27 1943-04-27 Frequency modulation receiver

Publications (1)

Publication Number Publication Date
GB594769A true GB594769A (en) 1947-11-19

Family

ID=23925312

Family Applications (1)

Application Number Title Priority Date Filing Date
GB7770/44A Expired GB594769A (en) 1943-04-27 1944-04-26 Improvements in and relating to frequency modulation receivers

Country Status (5)

Country Link
US (1) US2362806A (en)
BE (3) BE479153A (en)
CA (1) CA432262A (en)
FR (2) FR938602A (en)
GB (1) GB594769A (en)

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2519890A (en) * 1944-12-09 1950-08-22 Rca Corp Angle modulated wave receiver
US2501120A (en) * 1945-04-26 1950-03-21 Rca Corp Frequency modulation receiver tuning aid
US2525359A (en) * 1946-04-04 1950-10-10 Rca Corp Frequency modulation receiver tuning aid
US2620439A (en) * 1947-11-05 1952-12-02 Gen Electric Noise balancing circuits
US2612602A (en) * 1948-11-19 1952-09-30 Gen Electric Noise suppression circuit
CN107453346B (en) * 2016-05-30 2022-03-18 中国电力科学研究院 Load curve time interval division method suitable for power distribution network reconstruction

Also Published As

Publication number Publication date
BE479154A (en)
BE482547A (en)
FR961086A (en) 1950-05-03
BE479153A (en)
US2362806A (en) 1944-11-14
CA432262A (en) 1946-01-01
FR938602A (en) 1948-10-20

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