US1917291A - Method and means for eliminating fading - Google Patents

Method and means for eliminating fading Download PDF

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Publication number
US1917291A
US1917291A US274374A US27437428A US1917291A US 1917291 A US1917291 A US 1917291A US 274374 A US274374 A US 274374A US 27437428 A US27437428 A US 27437428A US 1917291 A US1917291 A US 1917291A
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United States
Prior art keywords
receiving
energy
tube
tubes
points
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Expired - Lifetime
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US274374A
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English (en)
Inventor
Harold H Beverage
Harold O Peterson
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RCA Corp
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RCA Corp
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Priority to BE360292D priority Critical patent/BE360292A/xx
Application filed by RCA Corp filed Critical RCA Corp
Priority to US274374A priority patent/US1917291A/en
Priority to DER78011D priority patent/DE516687C/de
Application granted granted Critical
Publication of US1917291A publication Critical patent/US1917291A/en
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/10—Polarisation diversity; Directional diversity

Definitions

  • This invention relates to the elimination of what has come to be known in radio signalling and speed transmission systems as fading.
  • the invention as herein disclosed is particularly adapted for use in the reception of'short wave radio signals and for use in locations where the efiiect of fading of signals is particularly troublesome, although it is to be understood that thesystem is likewise capable of efiicient use for all types of radio receiving systems, and is useful for long waves as well as short waves.
  • FIG. 1 of the drawing we have shown a receiving'system in which, for convenience of illustration, three antennae systems designated 1, 2 and 3 have been indicated. The energy picked up on each ofthe antennae systems 1, 2 and 3, which, as
  • antennae may be geographically separate antennae or antennae located at a single point but having different directive characteristics, is carried through tuned circuits of any desired character such as d, 5 and 6 which are all tuned to the same signal frequencies.
  • V which are designated as 13,14: and to direct energy from the several vacuum tubes to a common receiving ClICLllQ'Q'GHQZ'LlllY designated 16, wh1ch is connected with a common 7 receiver (not shown).
  • the grid returns from the several vacuum tubes, 10, l1 and 12 arelthen carried to several points 17, 18 and 19 on, an artificial line, generally designated 20.
  • the artificial line 20 preferably consists of series inductance 21 and shunt capacity 22.
  • the capacity elements 22 are associated with a common side of the artificial line which is grounded at 23 and with the inductance element 21.
  • the artificial line is substantially a wave length long electrically for a particular oscillator frequency to be hereinafter described, although it is to be understood that this limitation is unnecessary.
  • the capacity elements 22 constitute the capacity elements of this artificialline.
  • Connected across the end of the artificial line 20 is a damping resistance 24 for the purpose of damping reflections which might be possible upon the line.
  • an oscillator 26 ' which is preferably of, the low frequency type, and may be either an audible frequency or a superaudible frequency.
  • the grid returns of the vacuum tubes 10, 11 and 12 are connected to the artificial line at 17, 18 and 19.
  • These difi'erent points of connection to the artificial lines may or may not be nodal points on the artificial lines,'but preferably may be chosen as any point desired, of course, assuming that the artificial line is 360 electrical degrees long for the particular frequency of the oscillator 26. 'l Vhere the line 20 is 360 degrees long the points of connection of the grid return leads preferably will be spaced substantially 120 electrical degrees apart, but here again this spacing'of points is not essential to the operation of the invention, and the spacing may be of any desired separation along the artificial line regardless of how close or remote from a succeeding point.
  • the oscillator 26 which is coupled to the artificial line produces travelling'waves down the artificial line toward the direction of the damping resistance 24, and it is readily seen that these traveling waves might at one instant give a maximum positive voltage at the grid return connection point 17 for the grid 7 of the tube 10, and at the same instant would be almost minimum or negative voltage at the grid return connections 18 and 19 of the tubes 11 and 12.
  • the points 17 and 19 for connecting the tubes 10 and 12 to the artificial line will not be at a positive value but will be ap proaching a minimum value and the bias batteries 27 and 29 of the tubes 10 and 12 will control the grid potentials so that the tubes will be biased to cut-off.
  • the tube 11 Under conditions when a maximum positive voltage attains at point 18 the tube 11 will be the only tube to transfer energy to the receiving system.
  • the point- 19 will be at a maximum positive voltage and the points 17 and 18 will be at less positive voltages, so that in a manner similar to that described in connection with tubes 10 and 11 the tube 12 will transfer energy from the antenna system 3 through the coupling transformer to the circuit 16 of the receiving system, and at the same time the tubes 10 and 11 will be biased to cut-off.
  • the outputs of the tubes 10, 11 and 12 are all coupled inductively with the input circuit 16 of a common receiving system, so that maximum energy from tube 10 willbe transferred to the common receiving system at one instant, then at a later instant maximum energy from tube 11 and at a still later instant maximum energy from tube 12, and following with tube 10 in the manner described.
  • These maximums periodically change so that irrespective of the phase relationship of the radio frequency energy picked up on the separate antenna systems 1, 2 and 3 the energy is directed to the common receiving means and the effects of fading and phase relationship are no lou er detrimental and the energy can be combined absolutely and totally independent of any phase relationship of the signals at the various antennae.
  • Fig. 2 of the accompanying drawing u'e have shown a system which is a modified form of that shown by Fig. 1.
  • Fig. 2 in a similar manner to that shown by Fig. 1, signal energy is received and the cally spaced antennae systems or upon antcnna systems of difierent directive characteristics located at a common point, which have been designated 101, 102 and 103 respectively.
  • the energy received upon the antenna systems 101. 102, 103 is directed through any preferred or desirable form of tuned circuit 104.. 105. 106 to the input electrode 107, 108. 109 of the vacuum tubes 110, 111 and 112 which each direct their output energy to a common receiving circuit 113 which is connected with a single receiving means (not shown).
  • the output circuit of the tubes 110 in a similar manner to that shown by Fig. 1, signal energy is received and the cally spaced antennae systems or upon antcnna systems of difierent directive characteristics located at a common point, which have been designated 101, 102 and
  • each of the vacuum tubes 110. 111. and 112 has a bias battery designated 117. 118 and 119 respectively connected in the grid return lead.
  • the batteries 117,, 118 and 119 in the grid return circuit of the tubes 110, 111 and 112 normally bias the grid member of these tubes down to cut-off so that. under normal condi-' tions, no signals are transferred from the antenna systems 101, 102, 103to the combininq' circuit 113 leading to the receiving apparatus for all of the antenna systems.
  • Fig. 2 we have shown connections at 120, 121 and 122 for connecting geographi I the terminals .or leads connecting the ter minals of a'three phase oscillator of any desired character, and connected from the terminals 120, 121 and 122 in the form of a delta shaped net work.
  • the windings 123, 124v and 125 form the primary winding of the transformers 126, .127 and 128 respectively.
  • the secondary windings 129, 130 and 1310f the transformers 126, 127 and 128, respectively, are connected. and form a part of the arid return circuit of the tubes 110., 111 and 11.2, respectively. It is thus clearly seen that one phase of the three phase oscil ator is associated with the tube 110, another phase withthe tube 111 and the third phase with the tube 112.
  • the tube 110 When voltage is induced in the grid circuit of the tube through the secondary 129 of the transformer due to the fact that phase number one of the three phase oscillator is at a maximum positive point in its value, the tube 110 will function normally and the bias 117 which normally prevents plate current flow is overcome so that the grid member 107 is no longer biased to cut--. off and the tube functions normally and amplifies the radio frequency energy input from the antenna system 101 and passes this energy on through the common receiver by means of the output transformerlll which has its sec ondary winding, as above described, associated with the common combining circuit 113 for all of the various tubes in the system and forming a secondary winding in series with the secondary winding of the output transformer associated with the vacuum tubes 111 and 112.
  • the tube 112 will pass maximum energy to the combining circuit and the tubes 110 and 111 will pass minimum energy, after which the tube 112 passes energy to the con1- bining circuit the tube 110 will then be free to pass its maximum energy and the circle of operation will be continued.
  • the grids of the tubes may be periodically biased so that the three input tubes 110, 111 and 112 will be biased to cutoff and at first, one tube will pass maximum energy, then the next one Will pass maximum energy, and lastly the third tube will pass maximum energy through to the common receiving system, and the input signal phase will be entirely dissociated. It is readily seen. therefore, that this system will functhat described in In this case also, it is immaterial what the phase relationship of the radio frequency signal. energy upon the antenna 101, 102 and 103 may be, since the signals can, as has been above described, be combined absolutely independent of the phase relationship.
  • ⁇ Vhile we have described the system of Fig. 1 and the system of Fig. 2 as applicable to three geographically spaced antennae spaced at the same point, but having different directive characteristics it will be ap parentthat the system may be used for two antenna systems or more than three antenna systems by appropriate correction of the number of phasesfor the oscillator of Fig. 2, or appropriate positioning of the contact point for the grid return circuits of Fig. 1 to the artificial line 20 and, therefore, the system is one which readily lends itself to any number of antenna systems as may be chosen and be desirable.
  • Apparatus for avoiding the effects of fading on radio signals which includes, a plurality of antennae for receiving the same s1gnal, each of said antennae having different instantaneous response characteristics to the same signal effects, a common receiving point, means fordirecting the energy from said receiving point to said common receiving point, and means for continuously cyclically and successively associating one of said points with said common receiving point.
  • the method of overcoming fading efie'cts when receiving radio signals with receiving antennw of different instantaneous response characteristics and a radio frequency combining circuit which comprises, receiving the same signal bearing waves upon each of said antenna systems to produce a plurality of radio frequency signaling effects, continuously and successively associating each of said antenna systems with said radio frequency combining circuits, deriving signals in said combining circuit from said different antenna systems at successive and predetermined periods from each oi. said antenna systems, combining said derived signals and obtaining the transmitted signals from the combined signals.
  • the method of avoiding the effects of fading of radio signals which includes, receiving the same signal at a plurality of receiving points each exhibiting different in stantaneous response characteristics to the same signal, producing from said received signals a plurality of signal effects, introducing to each of said produced signal effects the effects of a low frequency, and alternatively and successively associating each of said receiving points with-a common receiving system, and interrupting the association of each of said separated receiving points with said receiving system at said low frequency rate.
  • the method of avoiding the effect of fading on radio signals which includes, receiving the same signal at a plurality of points of difierent instantaneous response characteristics and producing therefrom a plurality of signal effects, associating eachof said plurality of points with'a common receiving system for all of said receiving points, normally biasing each of said receiving points to cutoff, removing said cut-off bias from said point successively and continuously at an audible rate, and receiving the effect of the signal as received at said plurality of points intcrruptedly and successively in said common receiving system.
  • a system for the elimination of fading on short wave lengths which i cludes, a plurality of receiving means of different instantaneous response characteristics, a receiving circuit associated with each of said receiving systems and adapted to combine the energy from all of said systems, means for biasing each of said receiving systems normally to cut-off, and means for alternatively and successively removing the bias from said receiving systems and associating in succession said receiving means with said receiving circuit.
  • a system for the elimination of fading which includes, a plurality of receiving antennae each having different instantaneous response characteristics to the same signal effect, a vacuum tube amplifier for transferring the efiect received upon each of said antenna systems, a common receiving circuit for all of said antenna systems, said receiving circuit being associated with the output of all of said vacuum tube amplifiers, means for normally biasing each of said amplifiers to cut-01f, and means for successively and I continuously removing the bias from one of said amplifiers, whereby said amplifier passes received signal energy to said combining circuit and the remainder of said amplifiers are blocked with respect to the received signal energy and at each instant only one of said amplifiers is associated with saidreceivingcircuit.
  • a system'for the elimination of fading which includes,a plurality of receiving antenne each having different instantaneous response characteristic to the same signal effeet, a vacuum tube amplifier'for transferring the signal effects received upon each of said antenna systems, a common receiving circuit.
  • a coupling means for associating said receiving circuit with the output of all of said vacuum tube amplifiers, means for normally biasing each of said amplifiers to a cut-off potential, and means for successively and continually removing the said cut-01f bias from one of said amplifiers at a low frequency rate, whereby said amplifier passes received signal energy to said common receiving circuit and the remainder of said amplifiers are blocked with respect to the received signal energy and at each instant only one of said amplifiers is associated with said receiving system.
  • a system for eliminating'the efiects of fading of signals in radio signalling apparatus which includes, a plurality of receiving antenna systemseach having difierent instantaneous response characteristic to the same signal, a single receiving circuit for all of said antenna systems, a vacuum tube relay system ,for coupling each of said antenna systems with said single receiving system, means for normally maintaininga cut-off bias potential upon each of said vacuum tube relays, means for cyclically removing said cut-olfbias potential from said rela'ys and simultaneously associating each of said antenna systems and associated relays and its associated relay with said receiving circuit.
  • a system forthe elimination offading of signals in radio signalling apparatus which includes, a plurality of receiving antenna systems each having different instantaneous response characteristic to the same signal, a'vacuum tube relay system associated with each of said antenna systems, a single combining circuit for all of said antenna systems inductively associated with the output of each of said vacuum tubes, means for biasing the input electrode of each of said vacuum tubes to a predetermined cut-ofi potential, an artificial line, a connection between the grid electrode of each of said vacuum tubes and a point on said artificial line, a low frequency oscillator inductlvely coupled with said artificial line for producing wave trains propagating the length of said artificial line and means provided by said oscillator for successively and continuously applying a positive potential bias to the grids of said tubes for overcoming the cut-off bias and successively and continuously associating each of said vacuum tubes wlth sald common receivmg system,
  • a system for the elimination of fading of signals in radio receiving apparatus which includes a plurality of receiving antennae of different instantaneous response characteristics, an amplifier associated with each of said antenna systems, a common receiving circuit for receiving the signal effects from all of said antenna systems, means for coupling each of said amplifiers with said common receiving circuit, means for normally maintaining a cut-off potential upon each of said amplifiers, whereby signal energy reaching each of said amplifiers is bloc red from said common receiving circuit, an oscillator and means for associating each of said amplifiers with said oscillator whereby the cut-off bias potential is cyclically and successively removed from each of said amplifiers and the said amplifiers successively pass signal energy into said common receiving circuit and the signals received upon said plurality of antennae are combined in said receiving circuit independent of the phase relationship at the antenna and the effects of fading are substantially eliminated.
  • the method of overcoming fading effects during signalling which includes collecting in characteristically different fashions signal bearing transmitted energy at a plurality of separated points, and continuously and in predetermined sequence translating the energy collected at each point in order to obtain the transmitted signal.
  • the method of overcoming fading effects during signalling which includes collecting signal bearing energy at a plurality of separated points, producing potential waves, utilizing the waves produced to control the successive translation of the energy collected at each of the points, and combining the translated energy to obtain the 'transmitted signals.
  • the method of reducing fading during radio signallingv which includes collecting electromagnetic energy of like frequency at a plurality of points and translating successively and in predetermined order the energy collected at each point.:
  • the method of reducing fading during radio signalling which includes collecting electromagnetic energy of like frequency at a plurality of separated points, and translating successively and continuously in predetermined order the energy collected at each point automatically. 7 v
  • the method of reducingfading during radio signalling which includes collecting electromagnetic energy of like frequency at a plurality of separated points and translating successively at a supersonic frequency th energy collected at each point.
  • Radio signalling apparatus for overcoming fading of signal bearing radio waves comprising means for collecting electromagtermined order translating the energy collected at each point, and means for deriving transmitted signals from the translated energy.
  • Radio signalling apparatus comprising means for collecting electromagnetic energ of like frequency at a plurality of separated points and means for translating successively at a supersonic frequency the energy collected at each point.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Radar Systems Or Details Thereof (AREA)
  • Variable-Direction Aerials And Aerial Arrays (AREA)
US274374A 1928-05-02 1928-05-02 Method and means for eliminating fading Expired - Lifetime US1917291A (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
BE360292D BE360292A (enrdf_load_stackoverflow) 1928-05-02
US274374A US1917291A (en) 1928-05-02 1928-05-02 Method and means for eliminating fading
DER78011D DE516687C (de) 1928-05-02 1929-05-02 Verfahren zur Vermeidung von Schwundwirkungen bei drahtloser Signaluebertragung

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US274374A US1917291A (en) 1928-05-02 1928-05-02 Method and means for eliminating fading

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US1917291A true US1917291A (en) 1933-07-11

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BE (1) BE360292A (enrdf_load_stackoverflow)
DE (1) DE516687C (enrdf_load_stackoverflow)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2729741A (en) * 1951-10-10 1956-01-03 Itt Diversity reception system
US4575696A (en) * 1970-09-02 1986-03-11 Texas Instruments Incorporated Method for using interdigital surface wave transducer to generate unidirectionally propagating surface wave

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1104569B (de) * 1958-07-10 1961-04-13 Siemens Ag Antennenanlage, insbesondere Richtantennenanlage, fuer eine Raumdiversity-Empfangsanlage

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2729741A (en) * 1951-10-10 1956-01-03 Itt Diversity reception system
US4575696A (en) * 1970-09-02 1986-03-11 Texas Instruments Incorporated Method for using interdigital surface wave transducer to generate unidirectionally propagating surface wave

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Publication number Publication date
BE360292A (enrdf_load_stackoverflow)
DE516687C (de) 1931-01-30

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