US2433377A - Frequency discriminator circuits - Google Patents

Frequency discriminator circuits Download PDF

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Publication number
US2433377A
US2433377A US515016A US51501643A US2433377A US 2433377 A US2433377 A US 2433377A US 515016 A US515016 A US 515016A US 51501643 A US51501643 A US 51501643A US 2433377 A US2433377 A US 2433377A
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US
United States
Prior art keywords
resistors
resistor
condenser
winding
secondary winding
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 - Lifetime
Application number
US515016A
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English (en)
Inventor
Grand Jesse S Le
Bossiere Edward La
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
Federal Telephone and Radio Corp
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
Priority to BE465457D priority Critical patent/BE465457A/xx
Application filed by Standard Telephone and Cables PLC filed Critical Standard Telephone and Cables PLC
Priority to US515016A priority patent/US2433377A/en
Priority to GB25211/44A priority patent/GB587212A/en
Priority to FR939061D priority patent/FR939061A/fr
Application granted granted Critical
Publication of US2433377A publication Critical patent/US2433377A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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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
    • H03D3/08—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 diodes, e.g. Foster-Seeley discriminator

Definitions

  • ThisY inventionV relates toimprovementsv in. fre-- quency discriminator circuits, and more: particu.- larly to such circuits as are adaptedto be used ⁇ with frequency modulation receivers.
  • An object of this invention is to provide a frequency discriminator circuit which is satisfactory atvery highv frequencies as well as at the morefusual, lower frequencies.
  • the invention provides a fre.- quency discriminator circuit ink which the diode' load resistors are not shunted byy any discriminator. or inputv circuitcondensers, and which will remain completelybalanced..
  • Fig. l is a circuit diagram of a preferred fornil offrequency discriminator in accordance with the pres ent invention
  • Fig. 2 is a circuit diagram of a modified. form offrequency discriminator.
  • this condenser is made of low capacity, loss of efficiency occurs dueto the reactance of the condenser becoming large at the carrier frequency.
  • a radio frequency choke serially connected With this condenser is unsuitable at higher frequencies', while if a large resistor is used instead of this choke, loss of ef.- ciency occurs due to the fact that thevalue of this resistor becomes comparable in value to that of the dioderesistors'.
  • the frequency discriminator circuit according to the present invention, anda preferred example of which is illustrated. in Eig. 1', overcomes thek aforementioned diflculties.
  • the frequency discriminator input coupling or transformer I0 has its primary and secondary windings coupled and one end of its secondary Winding connected to the anode I2 of one diode and4 theV cathode I4" of. a second diode, both di odes preferably being. embodied in a double diodev tube
  • cathode I4 of the one diode is connected toy the input, as from the prior intermediate fre-- quency or limiter stage, will be. connected to the center tap ofthe secondary Winding II of the coupling Ill as well as tothe tuned primary cir cuit comprising condenser 8 and primary wind-'1 ing 9.
  • this input maybe connected through a blocking condenser 2.1 prior to the interconnection to the coupling It.. By grounding the common center terminal between the resistors I8 and 2D, it. will thus. be seeny that.
  • the modified form of invention shown in Fig.. 2 is identical with the principles of the inventionV illustrated in Fig. 1, but in this case the secondary winding II of the input coupling I0 is connected across the anodes I2 and I2 of the double diode I6, While the cathodes I4 and I4 are connected to ground through resistors 28 and 30 respectively.
  • the blocking condenser 21 is still so positioned that it, or any other discriminator circuit condenser, will not be in shunt with the resistors 28 and 30, the lower end of the primary winding 9 of the coupling I0 being also grounded, as heretofore described.
  • the diierence between the Voltage drops across resistors 28 and 30 is measured by the balanced output circuit consisting of condensers 32 and 34 and resistors 36 and 38, this output being applied to the grids 40 and 42 of the double triode 26 having anodes 44 and 48 connected to a source of anode potential and, connected for equal amplitude amplications but for 180 phase shift in one section, and 0 phase shift in the other.
  • This arrangement comprises connecting cathodes 50 and 52 serially through resistors 54 and 56, their midpoint being connected to ground, a bypass condenser being connected across resistor 58, and will result in a completely balanced output taken from cathode 50 through condenser 60 and anode 48 through condenser 62, while at the same time the only capacity in shunt with the diode resistors 28 and 30 will be the inter-tube capacities and the external wire capacity, if any.
  • Frequency discriminator circuit including, in combination, input coupling means comprising an input transformer having primary and secondary windings, means galvanically connecting one end of said primary winding to the substantial midpoint of said secondary winding, a condenser in shunt with each winding and forming with each a tuned circuit, a first resistor, iirst rectier means serially connecting one end of the secondary winding t one end of said resistor, a second resistor, second rectier means serially connecting the other end of said secondary winding to one end of said second resistor, means having negligibly low loss interconnecting the other end of the primary winding with the other end of the two resistors, and means deriving and comparing the potentials across said two resistors.
  • Frequency discriminator circuit including, in combination, input coupling means comprising an input transformer having primary and secondary windings, means galvanically connecting one end of said primary winding to the substantial midpoint of said secondary winding, a condenser in shunt with each winding and forming with each a tuned circuit, a rst resistor, rst rectifier means serially connecting one end of the secondary winding to one end of said resistor, a second resistor, second rectier means serially connecting the other end of said secondary Winding to one end of said second resistor, means galvanically comparing the potentials tron discharge devices each having an anode, a
  • Frequency discriminator circuit including, in combination, input coupling means comprising an input transformer having primary and secondary windings, means galvanically connecting one end of said primary winding to the substantial midpoint of said secondary winding, a condenser in shunt with each winding and forming with each a tuned circuit, a rst resistor, rst rectier means having an anode and a cathode, means connecting said anode to one end of said secondary winding and said cathode to one end of said resistor, a second resistor, second rectier means having an anode and a cathode, means respectively connecting the cathode of the second rectifier means to the other end of said secondary winding and the anode to one end of the second resistor, means grounding the other end of said primary winding and the other ends of said two resistors, and translating means responsive to the sum of the voltages across the two resistors including a pair of electron discharge devices each having an anode, a cathode and
  • Frequency discriminator circuit including, in combination, input coupling means comprising an input transformer having primary and secondary windings, means galvanically connecting one end of said primary winding to the substantial midpoint of said secondary winding, and a condenser in shunt with each winding and forming with each a tuned circuit, a first resistor, rst and second rectifier means each having an anode and a cathode, a pair of resistors, means respectively connecting the anodes of said two rectifier means to opposite ends of said secondary winding, means respectively connecting the cathodes of said two rectifier means to one end of said resistors, means grounding the other end of said primary winding and' the other ends of said resistors, and translating means responsive to the diierence between the voltage across the resistors including a pair of electron discharge devices each having an anode, a cathode and a grid with their grids coupled respectively to the one end of each of said resistors, a third and fourth resistor having one end of each connected respectively

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Measurement Of Current Or Voltage (AREA)
  • Digital Transmission Methods That Use Modulated Carrier Waves (AREA)
US515016A 1943-12-20 1943-12-20 Frequency discriminator circuits Expired - Lifetime US2433377A (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
BE465457D BE465457A (en)) 1943-12-20
US515016A US2433377A (en) 1943-12-20 1943-12-20 Frequency discriminator circuits
GB25211/44A GB587212A (en) 1943-12-20 1944-12-15 Frequency discriminator circuits
FR939061D FR939061A (fr) 1943-12-20 1946-03-29 Circuits discriminateurs de fréquence

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US515016A US2433377A (en) 1943-12-20 1943-12-20 Frequency discriminator circuits

Publications (1)

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US2433377A true US2433377A (en) 1947-12-30

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US515016A Expired - Lifetime US2433377A (en) 1943-12-20 1943-12-20 Frequency discriminator circuits

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US (1) US2433377A (en))
BE (1) BE465457A (en))
FR (1) FR939061A (en))
GB (1) GB587212A (en))

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2525359A (en) * 1946-04-04 1950-10-10 Rca Corp Frequency modulation receiver tuning aid

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2282105A (en) * 1940-10-16 1942-05-05 Rca Corp Detection of frequency modulated waves
US2286410A (en) * 1941-04-09 1942-06-16 Rca Corp Frequency modulation receiver tuning indicator
US2296056A (en) * 1939-08-16 1942-09-15 Rca Corp Frequency modulation receiver

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2296056A (en) * 1939-08-16 1942-09-15 Rca Corp Frequency modulation receiver
US2282105A (en) * 1940-10-16 1942-05-05 Rca Corp Detection of frequency modulated waves
US2286410A (en) * 1941-04-09 1942-06-16 Rca Corp Frequency modulation receiver tuning indicator

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2525359A (en) * 1946-04-04 1950-10-10 Rca Corp Frequency modulation receiver tuning aid

Also Published As

Publication number Publication date
BE465457A (en))
GB587212A (en) 1947-04-17
FR939061A (fr) 1948-11-03

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