GB481888A - Improvements relating to frequency selective systems and to systems for the reception of frequency-modulated waves - Google Patents

Improvements relating to frequency selective systems and to systems for the reception of frequency-modulated waves

Info

Publication number
GB481888A
GB481888A GB25444/36A GB2544436A GB481888A GB 481888 A GB481888 A GB 481888A GB 25444/36 A GB25444/36 A GB 25444/36A GB 2544436 A GB2544436 A GB 2544436A GB 481888 A GB481888 A GB 481888A
Authority
GB
United Kingdom
Prior art keywords
valve
frequency
grid
inductance
capacity
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
GB25444/36A
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 GB481888A publication Critical patent/GB481888A/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
    • 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
    • H03D3/12—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 discharge tubes having more than two electrodes

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Power Engineering (AREA)
  • Amplifiers (AREA)
  • Near-Field Transmission Systems (AREA)

Abstract

481,888. Wireless receiving systems. STANDARD TELEPHONES & CABLES, Ltd. Sept. 18, 1936, No. 25444. Convention date, Jan. 23. [Class 40 (v)] A demodulator for frequency-modulated waves comprises a valve with two grids normally biassed to prevent anode current flow and adapted to be excited in phase from an incoming wave or in opposite phase in dependence upon whether said wave is above or below a predetermined frequency. As shown valves 5, 6 with their outputs in push-pull are fed from a series resonant circuit comprising capacity 3 and inductance 4 and tuned to the mean incoming frequency. The cathode 10 of valve 5 is connected to the outer end of capacity 3, the grid 11 to the outer end of inductance 4 and the grid 12 to the junction of the inductance and capacity. The connections of the cathode 14 and first grid 15 of valve 6 are the reverse of those of the corresponding electrodes of .valve 5. Filter elements 25, 26, 47 prevent radio frequencies from reaching the output transformer 23, 24 which passes on the resulting amplitude variations, corresponding to the modulating signal at the transmitter, to the audio frequency amplifier 45. The resonant circuit 3, 4 may be replaced by a series arrangement of two parallel tuned circuits 49, 50 and 51, 52, Fig. 4,' tuned above and below the mean received frequency, by a conjoint control 55. A separate rectifier may be provided for an amplitudemodulated carrier produced by a single valve arranged in a similar manner to those in Fig. 1 and provided with a further screen grid, Fig. 6 (not shown). In a further embodiment the demodulating valve is arranged to act also as an amplitude limiter and is provided with a neutralizing circuit, Fig. 9 (not shown).
GB25444/36A 1936-01-23 1936-09-18 Improvements relating to frequency selective systems and to systems for the reception of frequency-modulated waves Expired GB481888A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US60420A US2100394A (en) 1936-01-23 1936-01-23 Reception of frequency modulated waves and circuits therefor

Publications (1)

Publication Number Publication Date
GB481888A true GB481888A (en) 1938-03-18

Family

ID=22029352

Family Applications (1)

Application Number Title Priority Date Filing Date
GB25444/36A Expired GB481888A (en) 1936-01-23 1936-09-18 Improvements relating to frequency selective systems and to systems for the reception of frequency-modulated waves

Country Status (5)

Country Link
US (1) US2100394A (en)
DE (1) DE736084C (en)
FR (1) FR818511A (en)
GB (1) GB481888A (en)
NL (1) NL47076C (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2458943A1 (en) * 1979-06-05 1981-01-02 Victor Company Of Japan FREQUENCY MODULATED SIGNAL DEMODULATION CIRCUIT

Families Citing this family (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE759434C (en) * 1940-09-25 1953-05-04 Lorenz A G C Frequency-dependent voltage divider for converting a frequency-modulated alternating voltage into an amplitude-modulated one
US2423594A (en) * 1942-07-23 1947-07-08 Liebel Flarsheim Co Resonance indicating and controlling device
US2518129A (en) * 1943-10-23 1950-08-08 Honeywell Regulator Co Control device
US2558758A (en) * 1944-01-22 1951-07-03 Sperry Corp Radio velocity indicator
US2478311A (en) * 1946-03-04 1949-08-09 Marshall C Pease Circuit for determining carrier frequencies of frequency modulated signals
US2525780A (en) * 1947-01-14 1950-10-17 Charles E Dennis Electrical frequency discriminator circuit
US2499742A (en) * 1948-06-11 1950-03-07 Bell Telephone Labor Inc Frequency modulation detector
US2747146A (en) * 1952-02-12 1956-05-22 Cook Electric Co Frequency enseitive control apparatus

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2458943A1 (en) * 1979-06-05 1981-01-02 Victor Company Of Japan FREQUENCY MODULATED SIGNAL DEMODULATION CIRCUIT

Also Published As

Publication number Publication date
US2100394A (en) 1937-11-30
NL47076C (en) 1939-06-15
DE736084C (en) 1943-06-07
FR818511A (en) 1937-09-30

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