US2199820A - Coupling circuits - Google Patents

Coupling circuits Download PDF

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Publication number
US2199820A
US2199820A US171917A US17191737A US2199820A US 2199820 A US2199820 A US 2199820A US 171917 A US171917 A US 171917A US 17191737 A US17191737 A US 17191737A US 2199820 A US2199820 A US 2199820A
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US
United States
Prior art keywords
network
circuit
resistance
balanced
line
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
US171917A
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English (en)
Inventor
Danforth K Gannett
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.)
AT&T Corp
Original Assignee
Bell Telephone Laboratories Inc
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 Bell Telephone Laboratories Inc filed Critical Bell Telephone Laboratories Inc
Priority to US171917A priority Critical patent/US2199820A/en
Priority to US182658A priority patent/US2178453A/en
Priority to FR845376D priority patent/FR845376A/fr
Application granted granted Critical
Publication of US2199820A publication Critical patent/US2199820A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H11/00—Networks using active elements
    • H03H11/02—Multiple-port networks
    • H03H11/32—Networks for transforming balanced signals into unbalanced signals and vice versa, e.g. baluns

Definitions

  • FIG. 1 A first figure.
  • This invention relates to coupling circuits and more specifically to circuits for connecting a balanced line or network to an unbalanced line or network.
  • a coupling circuit for interconnecting a balanced line or network and an unbalanced line or network which makes use of a phase inverting device such as an electron discharge tube.
  • the input circuit of this phase inverting device is connected between one of the terminals of the balanced line or network and ground, While the output circuit of this device is connected directly to the unbalanced line or network.
  • the other half of the balanced line or network is connected, without passing through the phase inverting device, to the terminals of the unbalanced line or network.
  • one-half of the balanced line I or network is connected to the input of the first stage of a two-stage amplifier and the other half of the balanced line or network is connected to the input of a single stage amplifier.
  • the anode of the output tube in each amplifier is connected to the terminal of the unbalanced line or network which is not connected to ground or to a fixed potential.
  • the total gain of the two tubes comprising the two-stage amplifier is adjusted to equal the gain of the single tube in the one-stage amplifier. In this arrangement longitudinal noise potentials present in the balanced line or network are balanced out and are not present in the unbalanced line or network.
  • Fig. 1 shows a circuit for connecting a balanced line or network to an unbalanced line or network
  • Fig. 2 discloses a circuit which is a modification of that shown in Fig. 1.
  • Fig. 1 shows a circuit H! for connecting a balanced line or network I! toan unbalanced line or network I l.
  • Connected across the terminals l3 and M of the balanced line or network It are the high resistances l5 and It, the common terminal ll of which is connected to ground (or to a fixed potential with respect to ground).
  • a phase inverting tube It comprising a cathode 19, an anode 20 and a control grid 2! has its cathodegrid circuit connected by means of the coupling condenser 22 to the resistance 15.
  • the customary resistance 23 and biasing source of potential 24 are also included in the grid-cathode circuit.
  • the circuit between the cathode It and the anode'lll includes an anode resistance 25 and a source of anode potential 25.
  • a tap 21 on the resistance 25 is connected by means of a coupling condenser 28 to the terminal 29 of the unbalanced line or network H, the other terminal 30 of which is connected to ground or to the potential of the common terminal I? of the resistances l5 and I6 if this potential is other than ground.
  • the gain of the electron discharge device I8 is adjusted so that the potential impressed on the point 32 from the electron discharge device is equal to the potential of the terminal l4 minus the drop of potential across the condenser 3!.
  • the terminal M of the balanced line or network is connected through coupling condenser 3i, which is similar to the coupling condenser 22, to the point 32.
  • the ratio of the potential between terminals 29 and 30 of the unbalanced line or network to the current in terminal E3 of the balanced line or network can be shown by ordinary circuit theory to be,
  • a stage of amplification is added to each side of the circuit shown in Fig. 1 so that a two-stage amplifier comprising the tubes [8 and 40 in tandem is connected across the resistance l5 and a singlestage amplifier comprising the tube 44 is connected across the resistance IS.
  • the output circuits of the tubes 40 and 44 are connected in parallel.
  • the electron discharge device 40 comprising a cathode 4
  • the resistance 48 and the biasing battery 49 complete the input circuit of the electron discharge device 40 while the resistance 50 and the biasing source of potential 5
  • the tubes 40 and 44 have a common output resistance 52 and source of anode potential 53, the two anodes 42 and 43 being connected to the terminal 29 of the unbalanced line or network II by means of the coupling condenser 54.
  • the tube it can be adjusted to have a zero gain and the tubes 40 and 44 to have any appropriate gain but equal to each other.
  • the gain of the tube H3 is not made equal to zero, but is of any desired value.
  • the longitudinal noise currents through the resistance l5 are twice 4 reversed in phase so that they are approximately equal to the phase in the resistance l5, while the longitudinal noise currents through the resistance l6 are once reversed in phase by means of the phase inverting tube 44.
  • the longitudinal noise currents through resistances l5 and I6 are present in the resistance 52 but are substantiallydegrees out of phase with respect to each other.
  • Fig. 2 has the advantage over that of Fig. 1 that the longitudinal noise currents may be accurately, instead of only approximately, balanced out. That this is true is evident without resort to equations from the symmetry of the impedances to ground at the input of the circuit of Fig. 2, and also at its output.
  • a first circuit terminating in a shunt impedance the effective central point of which is maintained at a fixed potential and which has two external terminals
  • a second circuit one terminal of Which is maintained at said fixed potential and the second terminal of which is free to vary in potential
  • said coupling means comprising an electron discharge device having an anode, a cathode and a control electrode, means for connecting the control electrode of said electron discharge device to one external terminal of said first circuit, means for maintaining the cathode of said device at said fixed potential, a second electron discharge device having an anode, a cathode and a control electrode, means for maintaining the cathode of said second electron discharge device at said fixed potential, means for connecting the control electrode of said second electron discharge device to the anode of the first electron discharge device, a third electron discharge device having an anode, a cathode and a control electrode, means for connecting the control electrode of said third electron discharge device to the other external

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  • Amplifiers (AREA)
  • Networks Using Active Elements (AREA)
US171917A 1937-10-30 1937-10-30 Coupling circuits Expired - Lifetime US2199820A (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
US171917A US2199820A (en) 1937-10-30 1937-10-30 Coupling circuits
US182658A US2178453A (en) 1937-10-30 1937-12-31 Coupling circuits
FR845376D FR845376A (fr) 1937-10-30 1938-10-29 Circuits de couplage pour systèmes de transmission électriques

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US171917A US2199820A (en) 1937-10-30 1937-10-30 Coupling circuits
US182658A US2178453A (en) 1937-10-30 1937-12-31 Coupling circuits

Publications (1)

Publication Number Publication Date
US2199820A true US2199820A (en) 1940-05-07

Family

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Family Applications (2)

Application Number Title Priority Date Filing Date
US171917A Expired - Lifetime US2199820A (en) 1937-10-30 1937-10-30 Coupling circuits
US182658A Expired - Lifetime US2178453A (en) 1937-10-30 1937-12-31 Coupling circuits

Family Applications After (1)

Application Number Title Priority Date Filing Date
US182658A Expired - Lifetime US2178453A (en) 1937-10-30 1937-12-31 Coupling circuits

Country Status (2)

Country Link
US (2) US2199820A (fr)
FR (1) FR845376A (fr)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2441387A (en) * 1944-10-30 1948-05-11 Us Sec War Electronic squaring circuit
US2505061A (en) * 1948-06-30 1950-04-25 Bell Telephone Labor Inc Phase inverter circuit
US2605962A (en) * 1944-11-04 1952-08-05 France B Berger Instantaneous square-root-extracting circuit
US2613285A (en) * 1946-08-16 1952-10-07 Farnsworth Res Corp Balanced input high-frequency amplifier
US2626349A (en) * 1942-08-13 1953-01-20 Irving H Page Interference eliminating circuits
US2882351A (en) * 1955-02-03 1959-04-14 Philco Corp Neutralized amplifier circuit
US3219943A (en) * 1961-01-18 1965-11-23 Trw Inc Common mode rejection input circuit

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3614628A (en) * 1968-12-05 1971-10-19 Antennacraft Co Uhf-vhf antenna preamplifier

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2626349A (en) * 1942-08-13 1953-01-20 Irving H Page Interference eliminating circuits
US2441387A (en) * 1944-10-30 1948-05-11 Us Sec War Electronic squaring circuit
US2605962A (en) * 1944-11-04 1952-08-05 France B Berger Instantaneous square-root-extracting circuit
US2613285A (en) * 1946-08-16 1952-10-07 Farnsworth Res Corp Balanced input high-frequency amplifier
US2505061A (en) * 1948-06-30 1950-04-25 Bell Telephone Labor Inc Phase inverter circuit
US2882351A (en) * 1955-02-03 1959-04-14 Philco Corp Neutralized amplifier circuit
US3219943A (en) * 1961-01-18 1965-11-23 Trw Inc Common mode rejection input circuit

Also Published As

Publication number Publication date
US2178453A (en) 1939-10-31
FR845376A (fr) 1939-08-21

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