US2078974A - Modulating system - Google Patents

Modulating system Download PDF

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Publication number
US2078974A
US2078974A US89363A US8936336A US2078974A US 2078974 A US2078974 A US 2078974A US 89363 A US89363 A US 89363A US 8936336 A US8936336 A US 8936336A US 2078974 A US2078974 A US 2078974A
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US
United States
Prior art keywords
resistance
conductive
linear
bridge
carrier
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
US89363A
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English (en)
Inventor
Robert R Riesz
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
Priority to NL44525D priority Critical patent/NL44525C/xx
Application filed by Bell Telephone Laboratories Inc filed Critical Bell Telephone Laboratories Inc
Priority to US89363A priority patent/US2078974A/en
Application granted granted Critical
Publication of US2078974A publication Critical patent/US2078974A/en
Priority to GB14851/37A priority patent/GB478994A/en
Priority to FR824728D priority patent/FR824728A/fr
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03C—MODULATION
    • H03C1/00—Amplitude modulation
    • H03C1/52—Modulators in which carrier or one sideband is wholly or partially suppressed
    • H03C1/54—Balanced modulators, e.g. bridge type, ring type or double balanced type
    • H03C1/56—Balanced modulators, e.g. bridge type, ring type or double balanced type comprising variable two-pole elements only
    • H03C1/58—Balanced modulators, e.g. bridge type, ring type or double balanced type comprising variable two-pole elements only comprising diodes

Definitions

  • FIG. 1 A first figure.
  • This invention relates to modulating systems, and moreparticularl-yto modulating systems employing physically inert non-linear; resistance applying a signaling voltage across the points 2
  • resistance elements arrangediin the form of a Wheatstone bridge in l l a" modulating, system to effect: signal 'modulation of carrier waves.
  • relatively small"resistance connected in series in one carrier conductive arm and arelatively large in the output circuit.
  • FIG. 1 illustrates a preferred embodiment of the invention
  • Fig. 1A shows one'modification' of-the invention
  • Figs. 13, 1C and 1D illustrate-other modifications of the invention.
  • Fig. 1 illustrates a modulatingsystem-embody connectedin shunt with filters ll 'and l2f
  • the filter I l adapted to pass a band of modulating frequencies produced-at'a signaling source I3 is directly connected to the output filter l2.
  • a load M is connected across the output filter 12 which is adapted to pass side-band frequencies lying adjacent to the carrier vfrequency produced by a generator l5.
  • Leads l9 and 20 connecting filters l l and 12 are also joined to points 2i and 22 of the bridge network l0 whose points 24 and 25 are connected to filter 23 associated with the carrier generator l5.
  • the Wheatstone bridge network It! comprises physically inert non-linear resistance elements 29, 30, 3
  • the rectifiers are poled as indicated by the arrows in Fig. 1, such that nonlinear resistance elements 29 and 30 are poled in a carrier non-conductive direction toward common terminal 24 while non-linear resistance elements 3
  • Theoperation of. the W'heatstone bridge in a modulating system is well-known and consists in voltages together with the non-linear resistanceelements produce a modulation actionzwhereby the carrier-;cur-rents and signaling currents are combined in the well-known manner to effect a signal modulation of thecarrier Wave of the carrier suppressed type. This is most efficiently accomplished, when the non-linear resistance elements comprising the bridge network.- barebalanced to a high degree of precision in both the conductive and non-conductive directions with respect to carrier.
  • the invention comprises a variable resistance 33 connected in series with the non-linear resistance element 3
  • . is varied to producethe best. bridgebalance ,forthe conductive direction.
  • resistance 34 is varied to effect the most accurate bridge balance for the non-conductive direction. Accordingly, by alternate adjustments of the resistances 33 and 34, the bridge network ll! may be eventually balanced to a high degree of precision. Obviously, a precise balance is desirable so as to obtain maximum suppression of carrier waves in the output circuit.
  • resistance 33 is effective in only one arm in the conductive direction and one arm in the non-conductive direction, and further, that shunt resistance 34 is effective in connection with but one arm of the non-conductive direction. Inasmuch as resistance 33 has a relatively low value of the order of 5 ohms, it will not appreciably affect the balance in the non-conductive direction. Likewise, since resistance 34 has a relatively large value of the order of 5500 ohms, it will not appreciably influence the balance in the conductive direction.
  • connection of the series resistance 33 and shunt resistance 34 in the above combinations depends on the conducting and non-conducting resistance values of the non-linear resistance elements.
  • the respective resistance values may be indicated as follows: In balancing a Wheatstone bridge, it is essential that Then in the conducting direction,
  • resistance 34 is connected in shunt with resistance element 32; and 522 E If ao R31 resistance 34 is connected in shunt with resistance element 3
  • Fig. 1A illustrates a modified Wheatstone bridge network 35 that may be substituted for the bridge network ID of Fig. 1.
  • a potentiometer 36 is interposed between the non-linear resistance elements 3
  • and 32 may be varied simultaneously.
  • the potentiometer 36 is effective in both non-conductive arms as well as both conductive arms.
  • the potentiometer 36 has a relatively small resistance; therefore it will not appreciably afiect the balance in the non-conductive direction.
  • the resistance 34 is relatively large, hence it will not appreciably afiect the balance in the conductive direction.
  • the resistance 34 may be connected in shunt with either resistance element 3
  • bridge networks l0 and 35 may be balanced to a high degree of accuracy in a minimum of time when the four non-linear resistance elements are substantially identical.
  • a modulating system of the carrier suppressed type comprising a source of modulating Waves connected in an input circuit of the system, an output circuit, a balanced Wheatstone bridge comprising a physically inert non-linear resistance element in each of its arms, the Wheatstone bridge being interposed between the input and output circuits, a source of carrier Waves connected to the Wheatstone bridge for modulation therein by said modulating waves, and means for increasing the degree of suppression of the unmodulated carrier component by providing a more accurate bridge balance than is afiorded by balancing said non-linearresistance elements against one another comprising a resistance connected in series with a non-linear element in one arm of the bridge and a resistance connected in shunt relation to the non-linear element in a different arm of the bridge, said series and shunt resistances being proportioned to provide the required degree of balance.
  • a modulating system in which the series resistance has such a value as will unappreciably affect the bridge balance in the non-conductive direction while the shunt resistance has a value that will unappreciably affect the bridge balance in the non-conductive direction while the shunt resistance has a value that will unappreciably affect the bridge balance in the conductive direction.
  • a modulating system in which the resistance connected in series in an arm is in series with one of the non-linear resistance elements poled in a conductive direction away from a common terminal.
  • a modulating system in which the resistance connected in series is a potentiometer interposed between the two nonlinear resistance elements poled in the conductive direction away from a common terminal.

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  • Measuring Instrument Details And Bridges, And Automatic Balancing Devices (AREA)
  • Amplitude Modulation (AREA)
US89363A 1936-07-07 1936-07-07 Modulating system Expired - Lifetime US2078974A (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
NL44525D NL44525C (en:Method) 1936-07-07
US89363A US2078974A (en) 1936-07-07 1936-07-07 Modulating system
GB14851/37A GB478994A (en) 1936-07-07 1937-05-28 Carrier wave modulating systems
FR824728D FR824728A (fr) 1936-07-07 1937-06-18 Systèmes de modulation d'ondes porteuses

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US89363A US2078974A (en) 1936-07-07 1936-07-07 Modulating system

Publications (1)

Publication Number Publication Date
US2078974A true US2078974A (en) 1937-05-04

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ID=22217244

Family Applications (1)

Application Number Title Priority Date Filing Date
US89363A Expired - Lifetime US2078974A (en) 1936-07-07 1936-07-07 Modulating system

Country Status (4)

Country Link
US (1) US2078974A (en:Method)
FR (1) FR824728A (en:Method)
GB (1) GB478994A (en:Method)
NL (1) NL44525C (en:Method)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2516672A (en) * 1944-05-27 1950-07-25 Socony Vacuum Oil Co Inc Apparatus for measuring radiant energy
US2814780A (en) * 1953-07-20 1957-11-26 Engineering Lab Inc Bridge-type modulator mixer

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL158485B (nl) * 1951-01-11 Heyl & Co Werkwijze voor het bereiden van penicillamine en zijn farmaceutisch geschikte zuuradditiezouten.

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2516672A (en) * 1944-05-27 1950-07-25 Socony Vacuum Oil Co Inc Apparatus for measuring radiant energy
US2814780A (en) * 1953-07-20 1957-11-26 Engineering Lab Inc Bridge-type modulator mixer

Also Published As

Publication number Publication date
GB478994A (en) 1938-01-28
FR824728A (fr) 1938-02-15
NL44525C (en:Method)

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