GB617139A - Improvements in or relating to arrangements for modulating the frequency of an electric carrier wave - Google Patents

Improvements in or relating to arrangements for modulating the frequency of an electric carrier wave

Info

Publication number
GB617139A
GB617139A GB2829946A GB2829946A GB617139A GB 617139 A GB617139 A GB 617139A GB 2829946 A GB2829946 A GB 2829946A GB 2829946 A GB2829946 A GB 2829946A GB 617139 A GB617139 A GB 617139A
Authority
GB
United Kingdom
Prior art keywords
frequency
derived
paths
modulating
voltage
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
GB2829946A
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.)
STANDARD TETEPHONES AND CABLES
THOMAS FREDERICK STANLEY HARGR
Original Assignee
STANDARD TETEPHONES AND CABLES
THOMAS FREDERICK STANLEY HARGR
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 TETEPHONES AND CABLES, THOMAS FREDERICK STANLEY HARGR filed Critical STANDARD TETEPHONES AND CABLES
Priority to GB2829946A priority Critical patent/GB617139A/en
Publication of GB617139A publication Critical patent/GB617139A/en
Expired legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03C—MODULATION
    • H03C3/00—Angle modulation
    • H03C3/38—Angle modulation by converting amplitude modulation to angle modulation
    • H03C3/40—Angle modulation by converting amplitude modulation to angle modulation using two signal paths the outputs of which have a predetermined phase difference and at least one output being amplitude-modulated

Landscapes

  • Amplitude Modulation (AREA)

Abstract

617,139. Frequency modulation. STANDARD TELEPHONES & GABLES, Ltd., HARGREAVES, T. F. S., and FOULKES, E. A. Sept. 20, 1946, No. 28299. [Class 40 (v)] In a frequency modulating device an amplifier 10 including a frequency determining circuit 16, 17, tuned to the mean carrier frequency is associated with two feed-back paths for generating oscillations, one of the paths including an amplitude modulator fed from the terminals 27 and the two paths being arranged to produce respective phase shifts which differ by 90 degrees. A feedback voltage of constant magnitude is derived from a feedback circuit connected to the secondary 29 of a coupling transformer 15 the primary of which is connected to the anode of the valve 10. A voltage of variable magnitude, depending upon the instantaneous value of the modulating signal, is derived from a second feedback circuit connected to the secondary winding 19, the arrangement being such that the frequency generated and derived from the secondary winding 34 is varied with respect to the mean carrier frequency in accordance with the modulations. The frequency deviation is substantially proportional to the modulating signal voltage when the deviation is small. The modulated feedback path includes a network 20, 21, which introduces a phase shift of 90 degrees. The amplitude modulator comprises two full wave bridge rectifiers 24, 25, coupled by transformers 22, 23. Specification. 513,661 is referred to.
GB2829946A 1946-09-20 1946-09-20 Improvements in or relating to arrangements for modulating the frequency of an electric carrier wave Expired GB617139A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB2829946A GB617139A (en) 1946-09-20 1946-09-20 Improvements in or relating to arrangements for modulating the frequency of an electric carrier wave

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB2829946A GB617139A (en) 1946-09-20 1946-09-20 Improvements in or relating to arrangements for modulating the frequency of an electric carrier wave

Publications (1)

Publication Number Publication Date
GB617139A true GB617139A (en) 1949-02-01

Family

ID=10273440

Family Applications (1)

Application Number Title Priority Date Filing Date
GB2829946A Expired GB617139A (en) 1946-09-20 1946-09-20 Improvements in or relating to arrangements for modulating the frequency of an electric carrier wave

Country Status (1)

Country Link
GB (1) GB617139A (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE971380C (en) * 1953-01-19 1959-01-22 Philips Nv Device for generating oscillations frequency-modulated with a modulation signal
DE1268220B (en) * 1965-07-27 1968-05-16 Siemens Ag Frequency modulator
US5155455A (en) * 1989-08-01 1992-10-13 Plessey Overseas Limited Am/fm modulator in which am can be converted to fm by vector addition

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE971380C (en) * 1953-01-19 1959-01-22 Philips Nv Device for generating oscillations frequency-modulated with a modulation signal
DE1268220B (en) * 1965-07-27 1968-05-16 Siemens Ag Frequency modulator
US5155455A (en) * 1989-08-01 1992-10-13 Plessey Overseas Limited Am/fm modulator in which am can be converted to fm by vector addition

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