US2434955A - Modulating system - Google Patents

Modulating system Download PDF

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Publication number
US2434955A
US2434955A US500059A US50005943A US2434955A US 2434955 A US2434955 A US 2434955A US 500059 A US500059 A US 500059A US 50005943 A US50005943 A US 50005943A US 2434955 A US2434955 A US 2434955A
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US
United States
Prior art keywords
carrier
sideband
energy
output
signals
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
US500059A
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English (en)
Inventor
Sidney B Pickles
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 BE482825D priority Critical patent/BE482825A/xx
Application filed by Standard Telephone and Cables PLC filed Critical Standard Telephone and Cables PLC
Priority to US500059A priority patent/US2434955A/en
Priority to GB15863/44A priority patent/GB620656A/en
Application granted granted Critical
Publication of US2434955A publication Critical patent/US2434955A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S1/00—Beacons or beacon systems transmitting signals having a characteristic or characteristics capable of being detected by non-directional receivers and defining directions, positions, or position lines fixed relatively to the beacon transmitters; Receivers co-operating therewith
    • G01S1/02—Beacons or beacon systems transmitting signals having a characteristic or characteristics capable of being detected by non-directional receivers and defining directions, positions, or position lines fixed relatively to the beacon transmitters; Receivers co-operating therewith using radio waves

Definitions

  • I1 ⁇ l'1isinvention relates ⁇ to a modulating system and more particularly to ⁇ r a 'system "':l'esgn'e'dv for use in radio beacons. t Y
  • l 1t is ⁇ a principal objectof my invention' to-profuVide a modulating system which is particularly usefullfor obtaining:carrierfwavesmodulted with diiierent signals; so 1 theta the Kcarrier combined it'ztli each on these -signals'mayf apzearkat independentterrnirialsaV It i'sansti-ll further object off-my l-nveitir'f to nrovide a sim'ple monitoring circuit for use with the-beaconf-modulating; System which willv indicatetlhe degree of unbalance 1dirctlyfaft the transinittng end ofthe'bea'eon-o.l
  • I ⁇ provide a- ⁇ systerng;inwhiolfl a carrier wave-is modulated with@J rst and second signalin an unbalancedmodulator which produces "an outiiut of carrier freguency and thev signalV sifdebanils.
  • thesame .carrier frequency is modulated-with the two signa-1s in a balanc-d modulator, Tone of these; signals being: reversed in; "phase respectgtoi thegother imodulator. This produces noui-,put signalsi'debands.
  • Monitoringycan-.then be 'achieyed merely by coupling f a.'v ⁇ llter circuit t one of the outputterminalsandyconneeting an indicator irl- ⁇ the output ofthe n-t'erito show p'es'ene of unwanted signalsatthat termina-1:;
  • A'b'et't'er understanding of myinventionqand suona- ⁇ signal ⁇ 4sources which may 90 and V15() cycle sources. Any-f two;V differing ⁇ ffrequerioiesmaygbe used; as isf well understoodpfinthe art.
  • a c Jfier source I2 is arranged to supplycarrier'siinulf taneousITy-vto; an unbalanced-modulator.
  • an equi-signal radio beacon which may serve either as a localizer beacon at an aireld or as a course beacon for guiding an aircraft between given points.
  • I provide a monitoring circuit which may include a coupling loop 21 coupled to line 2S. Loop 21 supplies energy to a ilter 28 which is tuned to pass only sideband components from source I I. The output of filter 28 is coupled to a meter 29. When the circuit is properly balanced, there will be no component -from source Il in line 26 and meter 29 will read zero. However, in the case of any unbalance, meter 29 will give an indication and the degree of departure of this indication from zero will indicate roughly the degree of unbalance. Balance may be restored by adjusting phase shifter I1 to bring the energy into proper phase agreement at the bridge input terminal and by adjusting the amplitude of energy in the output of either or both of the modulators I3 and I4.
  • a second monitoring unit coupled by loop 21A to line 25 and provided with a filter 28A serving to pass only the signal component from source I0 and a meter 29A may be provided.
  • a filter 28A serving to pass only the signal component from source I0 and a meter 29A may be provided.
  • a single meter will serve the purpose of monitoring the entire station.
  • Fig. 2 I have shown an antenna arrangement which may be substituted for that of Fig. 1 when an equisignal glide path is desired.
  • the antenna arrangement of this figure corresponds substantially to that disclosed in an application for Letters Patent to Andrew Alford, Serial No. 442,069, filed May 7, 1942, now Patent 2,373,090, issued April 16, 1945.
  • energy from leads 25 and 23 is fed over lines 25A and 26A to vertically arranged horizontal loops 31 and 36.
  • Loop 31 is arranged at a height above the earth to produce a plurality of lobes having a null aligned with the desired angle of glide path.
  • Loop 36 is arranged at a lower height, for example, half the height of loop 31, so that it provides a radiation lobe overlapping the null produced from antenna 31. In this manner, an equi-signal glide path carrying differently characterized signals is provided for guiding the craft to a proper landing.
  • beacon arrangements may be used with the modulating system of my invention without departing from the spirit thereof.
  • other types of systems may be provided to furnish the original modulated waves applied to the conjugate network such as 2U.
  • any type of antenna desired may be substituted for the particular horizontal loop type illustrated in the drawings.
  • a system for providing a carrier modulated separately with two dilerent signals comprising rst means for supplying carrier energy and a first and a second signal sideband, second means for supplying said first and second sidebands with one of said sidebands being phase reversed with respect to the sideband from said first means, a network having two conjugate input terminals, two conjugate output terminals and phase reversing means between one of said input and one of said output terminals, means for respectively applying energy from said first and second means to said input terminals, and output means coupled to said output terminals for deriving said carrier energy and one of said sideband signals, respectively, from said output terminals.
  • a system according to claim 1 further comprising monitoring means coupled to one of said output means, comprising a lter tuned to pass the signal sideband dilering from that Wanted at the output terminal, and indicator means in the output of said filter.
  • a method of providing a carrier modulated separated with two different signals comprising producing a rst wave combination consisting essentially of carrier energy and rst and second signal sidebands, producing a second wave combination consisting essentially of said first and second sidebands with said first sidebands reversed in phase with respect to the corresponding sideband rst named, combining said first and second wave combinations in phase coincidence to provide a first resultant wave combination of said carrier and said second sideband, and combining said first and second wave combinations in phase opposition to provide a second resultant wave combination of said carrier and said first sideband.
  • a method according to claim 3 further comprising the step of measuring the unwanted sideband component in one of said resultant wave combinations to determine unbalance between said first and second wave combinations.
  • a beacon modulating system comprising a first signal source, a second signal source, a carrier frequency source, a balanced modulator, an unbalanced modulator, means for supplyingy carrier to both said modulators, means for coupling said first and second sources to one of said modu, lators, means for coupling said first and second sources to the other of said modulators with the signals from one of said sources in phase opposition to the corresponding signals supplied to said one of said modulators whereby carrier and sideband energy of both said signals appears at the output of said unbalanced modulator, and sidebands only at the output of said balanced modulator, a four terminal bridge networkhaving a transposition in one arm thereof, means for applying the outputs of said modulators, respectively, to diagonally opposite terminals of said bridge network whereby carrier energy and said first signal sidebands appears at one of the remaining terminals of said bridge, and carrier and said second signal sideband appears at the other terminal of said bridge.
  • a system according to claim 5 further comprising phase shifting means in the output of one of said modulators for shifting the phase of said bridge.
  • a system according to claim 5 further comprising output lines coupled to each of said remaining terminals of said bridge, and a monitoring circuit coupled to at least one terminal of said bridge, said monitoring circuit comprising a lter tuned to the frequency of the sideband of the signal not wanted at said one terminal and an indicating meter coupled to the output of said lter.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
  • Arrangements For Transmission Of Measured Signals (AREA)
  • Transmitters (AREA)
US500059A 1943-08-26 1943-08-26 Modulating system Expired - Lifetime US2434955A (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
BE482825D BE482825A (en)) 1943-08-26
US500059A US2434955A (en) 1943-08-26 1943-08-26 Modulating system
GB15863/44A GB620656A (en) 1943-08-26 1944-08-18 Modulating system for radio beacons

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US500059A US2434955A (en) 1943-08-26 1943-08-26 Modulating system

Publications (1)

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US2434955A true US2434955A (en) 1948-01-27

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US500059A Expired - Lifetime US2434955A (en) 1943-08-26 1943-08-26 Modulating system

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BE (1) BE482825A (en))
GB (1) GB620656A (en))

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2577443A (en) * 1946-12-12 1951-12-04 Hartford Nat Bank & Trust Co Radio beacon system
US3483560A (en) * 1967-06-29 1969-12-09 Centre Nat Rech Scient Radio navigation system having automatic error compensation
US3938155A (en) * 1974-07-15 1976-02-10 Wilcox Electric, Inc. High stability modulator for instrument landing systems

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1918402A (en) * 1933-02-07 1933-07-18 Central Scientific Co Radio demonstration apparatus
US2302143A (en) * 1939-09-19 1942-11-17 Internat Telephone & Radio Mfg High frequency voltmeter
US2310202A (en) * 1941-03-01 1943-02-09 Fed Telephone & Radio Corp Electronic beacon modulator

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1918402A (en) * 1933-02-07 1933-07-18 Central Scientific Co Radio demonstration apparatus
US2302143A (en) * 1939-09-19 1942-11-17 Internat Telephone & Radio Mfg High frequency voltmeter
US2310202A (en) * 1941-03-01 1943-02-09 Fed Telephone & Radio Corp Electronic beacon modulator

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2577443A (en) * 1946-12-12 1951-12-04 Hartford Nat Bank & Trust Co Radio beacon system
US3483560A (en) * 1967-06-29 1969-12-09 Centre Nat Rech Scient Radio navigation system having automatic error compensation
US3938155A (en) * 1974-07-15 1976-02-10 Wilcox Electric, Inc. High stability modulator for instrument landing systems

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Publication number Publication date
GB620656A (en) 1949-03-29
BE482825A (en))

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