US2486076A - Circuit arrangement for changing the frequency of electrical oscillations - Google Patents

Circuit arrangement for changing the frequency of electrical oscillations Download PDF

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Publication number
US2486076A
US2486076A US697769A US69776946A US2486076A US 2486076 A US2486076 A US 2486076A US 697769 A US697769 A US 697769A US 69776946 A US69776946 A US 69776946A US 2486076 A US2486076 A US 2486076A
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United States
Prior art keywords
frequency
circuit
feedback
voltage
control grid
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Expired - Lifetime
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US697769A
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English (en)
Inventor
Strutt Maximiliaan Julius Otto
Ziel Aldert Van Der
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Hartford National Bank and Trust Co
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Hartford National Bank and Trust Co
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Publication date
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    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03D—DEMODULATION OR TRANSFERENCE OF MODULATION FROM ONE CARRIER TO ANOTHER
    • H03D7/00—Transference of modulation from one carrier to another, e.g. frequency-changing
    • H03D7/06—Transference of modulation from one carrier to another, e.g. frequency-changing by means of discharge tubes having more than two electrodes
    • H03D7/10—Transference of modulation from one carrier to another, e.g. frequency-changing by means of discharge tubes having more than two electrodes the signals to be mixed being applied between different pairs of electrodes
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03D—DEMODULATION OR TRANSFERENCE OF MODULATION FROM ONE CARRIER TO ANOTHER
    • H03D7/00—Transference of modulation from one carrier to another, e.g. frequency-changing
    • H03D7/06—Transference of modulation from one carrier to another, e.g. frequency-changing by means of discharge tubes having more than two electrodes
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F1/00—Details of amplifiers with only discharge tubes, only semiconductor devices or only unspecified devices as amplifying elements
    • H03F1/26—Modifications of amplifiers to reduce influence of noise generated by amplifying elements
    • H03F1/28—Modifications of amplifiers to reduce influence of noise generated by amplifying elements in discharge-tube amplifiers

Definitions

  • second frequency-changing stage is formed by a hexode in which the (intermediate-frequency) oscillations changed in frequency are supplied to the inner control grid and the local oscillations .are supplied to the outer control grid while the feedback voltage for the negative feedback as well as the amplified signal of intermediate frequency are taken from the anode circuit.
  • This embodiment has the drawback that the amplification of the oscillations of intermediate frequency by the hexode cannot be controlled without acting at the same time upon the negative feedback, for if, at the occurrence of a strong ,signal, the amplification brought about by the hexode would be decreased in the usual manner, this would result in a decrease of the intensity of the negative feedback and therefore of the damping of the input circuit so that a great signal strength would be attended with an increased selectivity. Such an influence exerted on the feedback is of course undesirable.
  • the invention has for its object to provide a circuit-arrangement with which it is possible to control the amplification of the second frequencychanging stagev for the oscillations changed in frequency without simultaneously acting upon the intensity of the negative feedback.
  • the second frethe local oscillations, to the inner control grid and a controlling voltage for the control of the amplification is supplied to the outer control grid, the feedback current or voltage for the negative feedback and the amplified oscillations changed in frequency being taken from the cathode lead and from the anode circuit respectively.
  • the drawing represents a circuit-arrangement for the change of frequency which comprises a hexode l.
  • the circuit of the inner control grid of this hexode comprises an input oscillatory circuit 2 to which is supplied the signal to be changed in frequency (input signal) which is taken from an aerial 3.
  • the anode circuit comprises an intermediate-frequency circuit 4 across which appear the (intermediate-frequency) oscillations changed in frequency.
  • the circuit of the outer control grid comprises an inductance coil 5 which is coupled to a local oscillator 6 which is represented by a block.
  • the anode circuit of the hexode further comprises an inductance coil 1 which is .coupled to the oscillator 6 in the same manner as the coil 5.
  • the oscillations of the oscillator frequency which appear across the coil l are supplied, through the intermediary of a .coupling condenser 8, to the inner control grid of a second hexode 9.
  • This second hexode acts simultaneously as an intermediate-frequency amplifier and as a second frequency changer.
  • the amplified oscillations of intermediate frequency appear across a circuit it which is included in the anode circuit of the hexode 9 and are supplied via terminals l I to the remainder of the circuit-arrangement.
  • a resistance I2 which serves to generate the required bias voltage for the inner control grid and which has connected in series with it a highfrequency choke .coil l3, this series-connection being shunted by a condenser I l.
  • the condenser M has so low a capacity that across this condenser is set up an appreciable voltage of the frequency of the input signal supplied to the inner control grid.
  • This voltage is supplied through a condenser l5 to the inner control grid, owing to which a positive feedback for the input signal is obtained. It may be noticed that this positive feedback is obtained 0wing to the fact, that, together with the condensers l4 and IS, the circuit 2 is connected to the tube l in a three-point system of the so-called Colpittstype.
  • a resistance l6 in series with a high-frequency choke coil 11 is provided in a similar manner a resistance l6 in series with a high-frequency choke coil 11, said series connection being shunted by a condenser i8 of comparatively low capacity. Since, in addition to the intermediate-frequency oscillations, a voltage of the oscillator frequency is also supplied to the inner control grid of the tube 9, a current of the frequency of the input signal is set up in the cathode lead of this tube. The voltage of this frequency which appears across the condenser I8 is supplied through a condenser I9 to the inner control grid of the hexode I, owing to which a negative feedback for the input signal is obtained.
  • the voltages of oscillator frequency which are supplied to the hexodes l and 9 are mutually in phase and that the tube l causes in the known manner a phase displacement of 180 so that the voltage of the input signal frequency which is set up across the condenser 18 is in anti-phase with the voltage across the condenser 14.
  • the feedback brought about by the condensers i8 and I9 is opposite in phase to the feedback brought about by the condensers and 15.
  • the parts of the circuit arrangement which have hitherto been described function as follows: Since the conversion conductance of a frequency changer is always less than the mutual conductance in the case of amplification, the signal to noise ratio in the intermediate-frequency anode current is always smaller than that in the current of the input signal frequency. Besides, the oathode current always constitutes a smaller noise component than the anode current since the current distribution fluctuations between the anode and the screen grids have no influence on the cathode current.
  • the voltage of the input signal frequency which is set up across the condenser I4 is consequently particularly free from noises in comparison with the intermediate-frequency voltage set up across the circuit 4.
  • circuit-arrangement proposed for this purpose in the previously identified copending application exhibits the drawback that an automatic control of the amplification of the combined intermediate-frequency amplification and second frequency-changing stages was not possible without influencing the efiect of the negative feedback.
  • this drawback is eliminated owing to the fact that the control voltage for the automatic control of the amplification is supplied to a second control grid of the tube in question while the feedback voltage is taken from the cathode lead.
  • controlling voltage is supplied through a resistance 20 to the outer control gridof the hexode 9.
  • the controlling voltage acts in the usual manner on the intermediate-frequency anode current and consequently on the output voltage across the circuit in but it has no influence on the cathode current so that the effect of the negative feedback is not affected by the control.
  • a frequency converter system for changing a radio wave into an intermediate-frequency signal comprising a first mixer including an electron discharge device provided with at least a cathode, first and second control grids and an anode, a first resonant circuit tuned to the radio wave and coupled between the first control grid and the cathode, a second resonant circuit tuned to the intermediate-frequency signal and coupled between the anode and the cathode, a feedback I network interposed between the cathode and said first and second resonant circuits to develop a positive feedback wave proportional to'said radio wave, means to apply said positive feedback wave to said first control grid, a source of local oscillae tions and means to apply said local oscillations to said second control grid and to said'second resonant circuit, a second mixer including an electron discharge device provided with a cathode, a control grid and an anode, means to apply the local oscillations and the intermediate frequency signal appearing in the second resonant circuit of said first mixer as an input to said control
  • a frequency converter system for changing a radio wave into an intermediate frequency signal comprising a first mixer including an electron discharge device provided with at least a cathode, first and second control grids and an anode, a first resonant circuit tuned to the radio wave and coupled between the first control grid and the cathode, a second resonant circuit tuned to the intermediate-frequency signal and coupled be-- tween the anode and the cathode,-a feedback network interposed between the cathode and said first and second resonant circuits to developa positive feedback wave proportional to said radio wave, means to apply said positive feedback wave to said first control grid, a source of local oscillations and means to apply said local oscillations to said second control grid and to said second resonant circuit, a second mixer including an electron discharge device provided with a cathode, first and second control grids and an anode, means to apply the local oscillations and the intermediate-frequency signal appearing in the second resonant circuit of said first mixer as an input to the

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Superheterodyne Receivers (AREA)
US697769A 1942-04-16 1946-09-18 Circuit arrangement for changing the frequency of electrical oscillations Expired - Lifetime US2486076A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
NL245848X 1942-04-16
NL2486076X 1943-02-23

Publications (1)

Publication Number Publication Date
US2486076A true US2486076A (en) 1949-10-25

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Family Applications (1)

Application Number Title Priority Date Filing Date
US697769A Expired - Lifetime US2486076A (en) 1942-04-16 1946-09-18 Circuit arrangement for changing the frequency of electrical oscillations

Country Status (6)

Country Link
US (1) US2486076A (ko)
BE (1) BE450187A (ko)
CH (1) CH245848A (ko)
FR (2) FR894004A (ko)
GB (1) GB613681A (ko)
NL (1) NL60694C (ko)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2591264A (en) * 1947-08-14 1952-04-01 Hartford Nat Bank & Trust Co Television receiver
US2662172A (en) * 1950-02-21 1953-12-08 Sperry Prod Inc Oscillator cancellation frequency converter
US2691103A (en) * 1947-08-25 1954-10-05 Hartford Nat Bank & Trust Co Circuit-arrangement for controlling the amplitude and the frequency of an electricaloscillation
US2713118A (en) * 1951-05-04 1955-07-12 Robert W Hart Communication system
US2963660A (en) * 1954-04-02 1960-12-06 Northrop Corp Signal frequency converter

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2662939A (en) * 1949-04-02 1953-12-15 Nowak Karl High selectivity amplifier
US2659776A (en) * 1949-05-13 1953-11-17 Nowak Karl Selective receiving and amplifying circuit
DE1081514B (de) * 1957-02-05 1960-05-12 Deutsche Bundespost Breitbandverstaerkerstufe

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2190243A (en) * 1937-12-14 1940-02-13 Robinson James Retroactive valve apparatus
US2223835A (en) * 1938-01-29 1940-12-03 Rca Corp Ultra high frequency device
US2256067A (en) * 1938-05-27 1941-09-16 Rca Corp Receiver selectivity control

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2190243A (en) * 1937-12-14 1940-02-13 Robinson James Retroactive valve apparatus
US2223835A (en) * 1938-01-29 1940-12-03 Rca Corp Ultra high frequency device
US2256067A (en) * 1938-05-27 1941-09-16 Rca Corp Receiver selectivity control

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2591264A (en) * 1947-08-14 1952-04-01 Hartford Nat Bank & Trust Co Television receiver
US2691103A (en) * 1947-08-25 1954-10-05 Hartford Nat Bank & Trust Co Circuit-arrangement for controlling the amplitude and the frequency of an electricaloscillation
US2662172A (en) * 1950-02-21 1953-12-08 Sperry Prod Inc Oscillator cancellation frequency converter
US2713118A (en) * 1951-05-04 1955-07-12 Robert W Hart Communication system
US2963660A (en) * 1954-04-02 1960-12-06 Northrop Corp Signal frequency converter

Also Published As

Publication number Publication date
FR894004A (fr) 1944-12-12
NL60694C (ko)
GB613681A (en) 1948-12-01
BE450187A (ko)
CH245848A (de) 1946-11-30
FR53342E (fr) 1945-10-16

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