GB750955A - Improvements in or relating to circuit arrangements for frequency-modulated waves - Google Patents

Improvements in or relating to circuit arrangements for frequency-modulated waves

Info

Publication number
GB750955A
GB750955A GB3511/54A GB351154A GB750955A GB 750955 A GB750955 A GB 750955A GB 3511/54 A GB3511/54 A GB 3511/54A GB 351154 A GB351154 A GB 351154A GB 750955 A GB750955 A GB 750955A
Authority
GB
United Kingdom
Prior art keywords
frequency
mixer
amplifier
output
frequency deviation
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
GB3511/54A
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.)
Siemens and Halske AG
Siemens AG
Original Assignee
Siemens and Halske AG
Siemens AG
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 Siemens and Halske AG, Siemens AG filed Critical Siemens and Halske AG
Publication of GB750955A publication Critical patent/GB750955A/en
Expired legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B14/00—Transmission systems not characterised by the medium used for transmission
    • H04B14/002—Transmission systems not characterised by the medium used for transmission characterised by the use of a carrier modulation
    • H04B14/006—Angle modulation
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03C—MODULATION
    • H03C3/00—Angle modulation
    • H03C3/02—Details
    • H03C3/06—Means for changing frequency deviation
    • 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
    • H04B1/66—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 for reducing bandwidth of signals; for improving efficiency of transmission

Abstract

750,955. Frequency modulation; radio signalling. SIEMENS & HALSKE AKT.- GES. Feb. 5, 1954 [Feb. 5, 1953], No. 3511/54. Class 40 (5). Negative feedback without demodulating an F.M. wave and without instability arising is applied to an F.M. wave of mean frequency f1 and frequency deviation F1 by a retroactive loop to a frequency changer. The loop also reduces the frequency deviation, and comprises a mixer M1 with intermediate frequency output f2, amplifier V, a network N<SP>1</SP> comprising two parallel connected paths one of them introducing a delay time t 0 , a limiter B, frequency multiplier N, filter S, and second mixer M2 producing the output frequency f1-f2 also applied to the first mixer M1. If Á,# are the transfer factors of the amplifier V and feedback loop. for the frequency deviation it is shown that where n is the frequency multiplying factor, w the angular frequency of the modulation, t 1 the delay time of the amplifier V and t 2 =¢ t 0 . K The value of t 0 is preferably chosen as to= -- fo where K is an integer and f o is the mean frequency of the frequency modulated wave. At initial high modulation frequencies, e.g. defined by w(t 1 +t 2 )=# liable to produce instability the value of Á# can therefore be arranged to have such a decreased value as to prevent this. The frequency deviation at the output of the mixer M2 being F1Á#/1+Á# decreases with modulation frequency, and the zeros of the frequency deviation may be arranged on the edge of the pass-band of the I.F. amplifier where the phase shift is the maximum. For the amplifier V, 1Á1=1, due to the frequency deviation being unchanged, but the phase is altered. The frequency deviation F1Á/1+Á# may be restored to the original value F1 by amplifying the output of M2 by a further amplifier V<SP>1</SP> similar to V, and taking the difference of its frequency deviation output FlÁ<SP>2</SP>/1+Á# with the output of V in a third mixer M3. As applied to a relay station a fourth mixer M4 may add a frequency difference #f to the retransmitted carrier frequency.
GB3511/54A 1953-02-05 1954-02-05 Improvements in or relating to circuit arrangements for frequency-modulated waves Expired GB750955A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE322498X 1953-02-05

Publications (1)

Publication Number Publication Date
GB750955A true GB750955A (en) 1956-06-20

Family

ID=6167590

Family Applications (1)

Application Number Title Priority Date Filing Date
GB3511/54A Expired GB750955A (en) 1953-02-05 1954-02-05 Improvements in or relating to circuit arrangements for frequency-modulated waves

Country Status (4)

Country Link
CH (1) CH322498A (en)
FR (1) FR1092830A (en)
GB (1) GB750955A (en)
NL (2) NL96201C (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3258694A (en) * 1964-01-03 1966-06-28 Multi-channel p.m. transmitter with automatic modulation index control

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3258694A (en) * 1964-01-03 1966-06-28 Multi-channel p.m. transmitter with automatic modulation index control

Also Published As

Publication number Publication date
FR1092830A (en) 1955-04-27
CH322498A (en) 1957-06-15
NL96201C (en)
NL184867B (en)

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