US2710350A - Ratio detector circuit for frequencymodulated oscillations - Google Patents

Ratio detector circuit for frequencymodulated oscillations Download PDF

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Publication number
US2710350A
US2710350A US381870A US38187053A US2710350A US 2710350 A US2710350 A US 2710350A US 381870 A US381870 A US 381870A US 38187053 A US38187053 A US 38187053A US 2710350 A US2710350 A US 2710350A
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United States
Prior art keywords
resistor
oscillations
ratio detector
frequencymodulated
circuit
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Expired - Lifetime
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US381870A
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English (en)
Inventor
Va Adelbertus Hermanus Nieveen
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Hartford National Bank and Trust Co
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Hartford National Bank and Trust Co
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    • 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

Definitions

  • This invention relates to a circuit for demodulating frequency-modulated oscillations by means of a ratiodetector of the type comprising two coupled circuits, two rectifiers and an RC-filter which ofiers substantially a short-circuit to the modulation frequencies. Its particular object is to improve in a simple manner the characteristic curve of a frequency-detecting circuit of the said kind on reception of larger input amplitudes.
  • the said RC-filter comprises a VDR-resistor.
  • VDR-resistor is to be understood to mean a resistor body, the resistance of which greatly decreases with increasing voltage irrespective of the direction of the voltage impressed.
  • the material used to constitute such a resistor is frequently silicon carbide.
  • the frequency-modulated input oscillations produced across the anode circuit of a tube 1 and required to be demodulated are fed via two circuits 2 and 3, which are about critically coupled and tuned to the input frequency, to two rectifiers 4 and 5 opposite in conductive direction, the output of which includes an RC-filter comprising a resistor 6 and a capacitor 7 and ofiering substantially no resistance to the modulation frequencies.
  • an RC-filter comprising a resistor 6 and a capacitor 7 and ofiering substantially no resistance to the modulation frequencies.
  • Via a coil 11 tightly coupled to the inductance of the primary circuit 2 the midpoint of the secondary circuit 3 is connected to a detector-output filter 8 so as to permit the demodulated oscillations to be abstracted from an ouput terminal 9.
  • a ratio detector exhibits full limiting only for a given value of the mean input amplitude.
  • a VDR-resistor 10 is connected in parallel with the RC-filter 6, 7.
  • the values C are widely differing for the various types in which the said resistors are to be had.
  • the value of B ranges about between 0.2 and 0.35.
  • Fig. 2 shows a known modification of the ratio detector of Fig. 1, the rectifiers 4 and 5 having the same conductive direction and their output including a detector filter 14 comprising two resistors 15 and 16 and two capacitors 17 and 18, the points of connection to which are connected via the above described RC-filter 6, 7 which according to the invention, has the VDR-resistor 10 connected in parallel therewith.
  • the other reference numerals designate like circuit elements as in Fig. 1.
  • a ratio detector for demodulating frequency-modulated oscillations comprising first and second resonant circuits in coupled relationship, means connected to supply said oscillations to said first resonant circuit, a pair of seriesconnected capacitors, a first diode having an anode connected to one end of said second resonant circuit and a cathode connected to one end of said series-connected capacitors, a second diode having an anode connected to the other end of said second resonant circuit and a cathode connected to the other end of said series-connected capacitors, a pair of series-connected resistors connected in parallel with said pair of series-connected capacitors, a coil coupled to said first resonant circuit and connected at one end to said second resonant circuit, the other end of said coil being connected to the junction between said pair of series-connected capacitors, a resistance-capacitance filter for by-passing modulation frequencies, said filter comprising a resistor and a capacitor connected in parallel combination, said combination being connected at one end to

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Digital Transmission Methods That Use Modulated Carrier Waves (AREA)
US381870A 1952-10-13 1953-09-23 Ratio detector circuit for frequencymodulated oscillations Expired - Lifetime US2710350A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL2710350X 1952-10-13

Publications (1)

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US2710350A true US2710350A (en) 1955-06-07

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US381870A Expired - Lifetime US2710350A (en) 1952-10-13 1953-09-23 Ratio detector circuit for frequencymodulated oscillations

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US (1) US2710350A (pt)
BE (1) BE523441A (pt)
FR (1) FR1084893A (pt)
NL (1) NL173091B (pt)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2878384A (en) * 1954-10-26 1959-03-17 Rca Corp Angle modulation detector
US2880315A (en) * 1954-10-05 1959-03-31 Gen Electric Angular modulation detector
US2980332A (en) * 1956-10-26 1961-04-18 Gen Electric Electronic curve follower and analog computer
US3130372A (en) * 1960-07-28 1964-04-21 Blair J Zajac Ratio detector with zener diode voltage regulator
US3159743A (en) * 1956-10-26 1964-12-01 Gen Electric Electronic curve follower and analog computer
US3585513A (en) * 1969-05-02 1971-06-15 Motorola Inc Frequency modulation discriminator having first branch with resonator and second branch providing voltage and temperature compensation
US4342000A (en) * 1979-04-04 1982-07-27 Nippon Gakki Seizo Kabushiki Kaisha FM Detecting circuit

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2282910A (en) * 1940-10-31 1942-05-12 Rca Corp Variable frequency detector system
US2309481A (en) * 1941-03-01 1943-01-26 Gen Electric Frequency monitoring system
US2572424A (en) * 1947-09-11 1951-10-23 Du Mont Allen B Lab Inc Frequency modulation ratio detector

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2282910A (en) * 1940-10-31 1942-05-12 Rca Corp Variable frequency detector system
US2309481A (en) * 1941-03-01 1943-01-26 Gen Electric Frequency monitoring system
US2572424A (en) * 1947-09-11 1951-10-23 Du Mont Allen B Lab Inc Frequency modulation ratio detector

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2880315A (en) * 1954-10-05 1959-03-31 Gen Electric Angular modulation detector
US2878384A (en) * 1954-10-26 1959-03-17 Rca Corp Angle modulation detector
US2980332A (en) * 1956-10-26 1961-04-18 Gen Electric Electronic curve follower and analog computer
US3159743A (en) * 1956-10-26 1964-12-01 Gen Electric Electronic curve follower and analog computer
US3130372A (en) * 1960-07-28 1964-04-21 Blair J Zajac Ratio detector with zener diode voltage regulator
US3585513A (en) * 1969-05-02 1971-06-15 Motorola Inc Frequency modulation discriminator having first branch with resonator and second branch providing voltage and temperature compensation
US4342000A (en) * 1979-04-04 1982-07-27 Nippon Gakki Seizo Kabushiki Kaisha FM Detecting circuit

Also Published As

Publication number Publication date
NL173091B (nl)
FR1084893A (fr) 1955-01-25
BE523441A (pt)

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