US 2034738 A
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Description (OCR text may contain errors)
Patented Mar. 24, 1936Y A l- 2,034,738
UNITED STATES invii;Nrv OFFICE RADIO TELEGRAPH REPEATER Harold H. Beverage, Riverhead, N. Y., assigner v to Radio Corporation of America, a corporation of Delaware Application October 31, 1932, Serial No. 640,376 1 Claim. (Cl. Z50-15) This invention relates to radio signal relaying in the drawing has been found to give a mean systems of the type wherein there is provided, in amplitude of the combined received signals in ciraddition to the customary transmitting and recuit I6 which is more constant than the amplitude ceiving terminating stations, one or more interof the wave received on any one antenna of the mediate repeating stations for relaying signals group. Observations made on various wave 5 between widely separated points. lengths have shown that the receiving antennae 10 tions 1n the strength of the received signal. A to obtain eicient results. 10 further difliculty in such systems has been ex- The combined rectified energy in the output perienced in obtaining a suitable power output circuit I0 is then passed on to a limiter-moduper channel when it is required to relay several lator device I I which is arranged to translate the signals simultaneously. rectified direct current pulses into a tone signal In accordance with the present invention there for further transmission over a landline L to 15 is provided a system which completely o-bviates transmitting and keying apparatus I2, the latter, these diiculties and which enables accurate and in turn, controlling radiation of the signals from eilcient communication, free from elects due t0 antenna I3. signal variations or fading. Device II may be any suitable circuit for In general, the invention contemplates the use changing the rectified energy received by it into 20 at the intermediate repeating Station, 0f a dia tone signal of a constant amplitude, irrespecversity receiver in combinatie-n with an amplitive of variations over moderate limits of the tude limiting device and a tone keying-modulatcombined rectier currents in circuit I0. The ing arrangement. An important characteristic of individual oscillations of the tone signal may be this repeating station, which is designed t0 auteof any desired frequency-in the present instance 25 matically repeat signals without the intervenpreferably an audio frequency since the signal tion 0f Operators, is the tota-1 absence 0f meis subsequently utilized for transmission over a Chancal relays and the @Onseqllent eliminatiOn landline L. One example of an arrangement for of inertia due to moving mechanical parts. effecting this resuIt is described in considerable Other features and advantages Will appear in detail in the patent to H. H. Beverage, et al., No. 30 the following detailed description which is ac- 1,874,866, supra, referring particularly to Figure companied by a single drawing sho-wing, in con- 2 there@ ventional form, a circuit diagram of a radio re- The resulting tone signal output sent out by laying system eInbOdying the principles 0f the limiting device II is chopped up or interrupted present inVeIltOH. at intervals corresponding to the interruptions of 35 Referring t0 the drawing, there is ShOWn a the signal characters received by the relay staconventional transmitting station A, in box form, tion B and is transmitted over line L to control arranged to send message waves to a receiving keying-transmitting apparatus I2 which may be station C, of any desired type, via an intermediate located at any desired distance from the diversity 40 relaying or repeating Station B- receiver and limiting-modulator device II. 40
In order to overcome fading and to insure the In order to overcome undesirable characterisreCeption of radio signals at the relay point7 sta` tics of the line L, which may cause objectionable tion B is provided with a diversity receiving sysparasitics in the transmitter |y the keying appa.. tem C Omprising essentially a. plurality 0f georatus at I2 is made to function substantially independently of the signal character envelope of the controlling tone received over landline L.
I'his may be accomplished by utilizing two values of the rectified tone envelope, one value to sudcombined in a common output circuit I0. Several glhulhenvuvgkgdglslhg tlrf suitable diversity receivers which may be used at .y the relaying station B and to which reference is rent and m thls Way prevent mtermedlate Values made are described in United States Patents Nos. of the tone or Startnig and endmg Values of the 1,819,589 and 1,874,866 granted August 18J 1931 tone, froml aiecting 1n any manner the flowof and August 30, 1932, respectively, to Messrs. H. H. the signaumg Current and the consequent radla' 55 Beverage and PeterSoIL tion from antenna. I3. apparatus for Since interference and fading eects at the eeCtng this result are knOWn in the art. F01 radio frequencies are diierent at points located eXaInDle. One methOd 0f aCCOmplishing such keyan appreciable distance apart from each other, ing at the transmitter l2, which is herein mensuch a diversity receiving arrangement as shown tioned only for purposes of illustration, is de- 60 2 scribed in U. S. Patent No. 1,887,236, granted November 8, 1932, to J. L. Finch.
The radiations emanating from antenna I3 are, of course, directed toward receiving terminal station C.
There is thus obtained, by means of the present invention, a radio relaying system in which the repeating station is entirely reliable with respect to such matters as suitable power output, freedom from static and fading, and automatic operation without the intervention of operators.
The combination with a' radio signal relaying station having transmitting and receiving terminating stations, of an intermediate repeating station comprising a. diversity receiving system employing a plurality of geographically spaced antennae, circuit connections for receiving, rectifying and combining the signals received over said pluralityv of antennae, means for translating said combined rectified signals into tone signals of constant amplitude irrespective of variations in said rectified signals, a transmitting antenna system, a line extending between said means and said transmitting antenna system, transmitting and keying apparatus connected to said antenna system for controlling radiation from said system substantially independently of the signal character envelope of the tone signal characters received over said line from said means.
HAROLD H. BEVERAGE.