GB555526A - Frequency modulation receivers - Google Patents

Frequency modulation receivers

Info

Publication number
GB555526A
GB555526A GB4158/42A GB415842A GB555526A GB 555526 A GB555526 A GB 555526A GB 4158/42 A GB4158/42 A GB 4158/42A GB 415842 A GB415842 A GB 415842A GB 555526 A GB555526 A GB 555526A
Authority
GB
United Kingdom
Prior art keywords
frequency
resistances
amplitude
effected
local oscillator
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
GB4158/42A
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 GB555526A publication Critical patent/GB555526A/en
Expired legal-status Critical Current

Links

Classifications

    • HELECTRICITY
    • H03ELECTRONIC CIRCUITRY
    • H03DDEMODULATION OR TRANSFERENCE OF MODULATION FROM ONE CARRIER TO ANOTHER
    • H03D3/00Demodulation of angle-, frequency- or phase- modulated oscillations
    • H03D3/001Details of arrangements applicable to more than one type of frequency demodulator
    • H03D3/003Arrangements for reducing frequency deviation, e.g. by negative frequency feedback
    • H03D3/004Arrangements for reducing frequency deviation, e.g. by negative frequency feedback wherein the demodulated signal is used for controlling an oscillator, e.g. the local oscillator

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Transmitters (AREA)
  • Circuits Of Receivers In General (AREA)

Abstract

555,526. Frequency modulation. STANDARD TELEPHONES & CABLES, Ltd. March 28, 1942, No. 4158. Convention date, Nov. 13, 1940. [Class 40 (v)] Relates to frequency-modulation radio receivers of the kind described in Specification 489,636 in which the detected signal is fed back to modulate in degenerative phase the frequency of the local oscillator, and consists in providing means for maintaining a substantially uniform amplitude of IF carrier despite variations in incoming carrier amplitude. The incoming wave passes through a frequency changer 42 and IF amplifier 44 to two parallel-connected amplifiers 56, 57 which have their output circuits 52, 54 tuned above and below the true IF., the coils of each tuned circuit being closely coupled. The tuned circuits feed rectifiers 58, 59 and load resistances 64, 65, and the detected signal appearing across the joint resistances is fed in push-pull to amplifiers 68, 69 and to the signal reproducer. The detected signal is also fed back through a network 49 of the kind described in Specification 514,567 to modulate the frequency of the local oscillator 43 in such sense as to reduce the frequency deviation of the incoming wave. Automatic tuning correction is also effected by smoothed D.C. voltages derived from the resistances 64, 65 and applied through the leads 73 to control the local oscillator. Changes of amplitude in the wave applied to the frequency discriminator are detected across resistances 81, 82 connected in series between earth and the junction of the resistances 64, 65. Slow changes are applied through a delay diode 84 and resistance 86 to modify the gain of the frequency-changer 42 and amplifier 44. More rapid changes are substantially eliminated by negative feed-back provided by resistance 81 and stabilizing network 89. The receiver may have two frequency-changing stages, the frequencycontrol being effected at the second stage, and the amplitude control at the first. Amplitude control may be effected by a limiter.
GB4158/42A 1940-11-13 1942-03-28 Frequency modulation receivers Expired GB555526A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US365424A US2272401A (en) 1940-11-13 1940-11-13 Frequency modulation receiver

Publications (1)

Publication Number Publication Date
GB555526A true GB555526A (en) 1943-08-26

Family

ID=23438857

Family Applications (1)

Application Number Title Priority Date Filing Date
GB4158/42A Expired GB555526A (en) 1940-11-13 1942-03-28 Frequency modulation receivers

Country Status (2)

Country Link
US (1) US2272401A (en)
GB (1) GB555526A (en)

Families Citing this family (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2527523A (en) * 1944-08-11 1950-10-31 Farnsworth Res Corp Frequency control system
US2551348A (en) * 1945-03-28 1951-05-01 Philco Corp Electrical apparatus
NL144559B (en) * 1949-01-27 Pechiney Saint Gobain PROCESS FOR THE PREPARATION OF ACTIVE ALUMINUM OXIDE AGGLOMERATES AND FORMED ALUMINUM OXIDE AGGLOMERATES OBTAINED BY THIS PROCESS.
US2692330A (en) * 1950-05-22 1954-10-19 Rca Corp Noise reduction arrangement
US2676247A (en) * 1950-07-28 1954-04-20 Hartford Nat Bank & Trust Co Circuit arrangement for silent tuning in frequency-modulation receivers
US3909725A (en) * 1957-03-29 1975-09-30 Massachusetts Inst Technology Frequency modulation receiver
US3053981A (en) * 1959-07-06 1962-09-11 Security First Nat Bank High-gain frequency modulation tuner
NL277424A (en) * 1961-04-25
US3231819A (en) * 1961-09-07 1966-01-25 Bell Telephone Labor Inc Intermodulation distortion correction of angle modulated transmission system by use of nonlinear cancellation circuit
JPS6042533Y2 (en) * 1977-02-23 1985-12-27 株式会社ケンウッド FM receiver
US4293818A (en) * 1979-01-22 1981-10-06 International Telephone And Telegraph Corporation Frequency modulation threshold extension demodulator utilizing frequency compression feedback with frequency drift correction
US4991226A (en) * 1989-06-13 1991-02-05 Bongiorno James W FM detector with deviation manipulation
US5034695A (en) * 1989-06-16 1991-07-23 Owen Joseph C Full threshold FM demodulator
US5691666A (en) * 1995-06-07 1997-11-25 Owen; Joseph C. Full threshold FM deviation compression feedback demodulator and method
US8045947B2 (en) * 2004-09-17 2011-10-25 Massachusetts Institute Of Technology RF power extracting circuit and related techniques

Also Published As

Publication number Publication date
US2272401A (en) 1942-02-10

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