US1291527A - Wireless receiving system. - Google Patents

Description

A. W. HULL.

WIRELESS RECEIVING SYSTEM. APPLICATION FILED MAR-10.1%].

E 1,291,527. Patented Jan. 1 1, i919.

Fig; l.

Inventor: Albert \X/.Hu.ll

Jog His flttovneg UNI ED STATES PATENT oFFIoE.

ALBERT H ULIJ, 0F SCHENECTADY. NEW YORK, ASSIGNOR TO, GENERAL ELECTRIC' COMPANY, ACOBPORATIQN OF NEW YORK. I

WIRELESS RECEIVING SYSTEM.

Receiving Systems, of which the following is a SPGQlfiCfitlOI};

y present invention relates to means for ampllfylng variable currents. and more particularly to means for amplifying and detectiug currents produced by wireless signals in a receiving antenna.

In a paper published in the Physical Rewz'ew of January, 1916, I have described an electron discharge device in which a negacorresponding variation in the number of second describ tion Serial No. 47,938, filed August 30, 1915.-

- second object of my invention is to provide a receiving circuit .which will be cape-- cially adapted for the reception of continuoi. dyne method.

tive resistance characteristic is obtained by producing, from an incandescent cathode.

-rece1ver a capacity of such value with re current between the tivoelectrod'es in an external circuit varies inversely as the potential-between the electrodes. With this device 'thevalue of the negative resistance may.

be varied b varying the temperature of the cathode and thereby varyin the number of primary electrons produce since a, variation in the number of primary electrons .which reachthe third electrode will cause a electrons emitted. This device is and claimed in my prior applica In a prior application, S..N.'101,729, filed June 5, 1916, I have described and claimed a modification of this device in which the value of the negative resistance may be v:1-.

ried by varying the potential of a discharge controlling member in proximity to the cathode.

mentioned be utilized I have also shown in the above or receiving wireless signals; The ob ect"of my presentmvention 15 to provide an improved circuit arrangement in which the device described in the applica-' tion referred tomay be utilized-for receiving wireless si als .whereby'the sensitiveness andselec'tivi of the receiving circuit be greatly increased.

ous wave signals by the so-called hetero.-

Specification of Letters Patent.

Application filed March 10, 1917. Seth 1N0. 154,025.

a plication how this devicemay f characteristic. of my'mventlon are pointed out with particularity in" the appended inconnection with In carrying 0ut the first object of my invention I provide inductance and capacity in Patented Jan .14 1919;:

circuit with the negative resistance, of such values that the circuit is resonant to the radio frequency of the, waves to be received. The circuit is so arranged that oscillations will not be produced unless the value of the. nega tiv'e resistance is greater or less than a certain critical value. When the circuit is arranged in this way and received oscillations {are impressed upon a controlling grid, the value of the negative resistance,.,w1ll healtered in such a way that oscillations will be produced in the circuit. As a result the selectivity and sensitiveness of the device or signals will 'be' greatly. incre'ased.- I also provide in conjunction with the telephone 11 order to provide a still further in? the degree of amplification of the received In attaining thesecond object of my in.-

vention I arrange the circuit containingftlieZ negative resistance in such a way that oscil,-.-

lations will be produced therein of a fre quency slightly-different from :the frequenc I of thereceived oscillations. As an the twp sets of oscillations will combineto" produce beats in the telephone receiver in accordance with the usual heterod-yne method.

The novel features which I believe to he claims. The invention, itself, however, both as to its organization andmethod of opera} tion, together with further objects and advantages thereof, will best be understood by reference to the following description taken the accompanyin draw-. ing in which Figures 1 and 2 show maticallytwo difierent modifications.

As indicated diagrammatically. in the hawing,- an evacuated receptaclcl is provided withfa cathode which is preferably which' may be by means of the rent-between the electrodes is not accompanied ,by any visible manifestationoil' gas ionization, such for example, as blue low. In the operation of this device a.de nite positive potential is applied to thean'ode d-by means of the battery 7, the cathfle being considered as at zero or earth potential. If the cathode. is heated to incandescence there will be a dew-of electrons from cathode to anodeu It the third electrode 5 is at the same potential as the cathode no electrons will be received thereby. It,

however, a small positive potential less than that of the. anode electrode a portion varies inversol electrodes.-

aplied to the not obattery 8, t,

numbered e ectrons 'andreachzthe third electrode and the current in theextern electrode increases faster than t of primary point,

is applied .to the third of the electrons will pass through the anode and reach the third electrode; The velocityv with which these electrons will strike the third electrode will depend upon the potentialybetweeu it and the cathode.

If this potential is increased the .vel'ocit will increaseuntil the electrons, striking t e third electrode, are able, by their impact, to "liberate secondary electrons.

' These secondary electrons leavingthe third electrode will be attracted to the more posithe anode. As the potential is incneased,-

a point" will be reached at which her of secondary electrons-leavin the numthe third e number electrons received, and the cur;- rent whic will, flow in. the external circuit between the cathode and third will begin to decrease. its the the third electrode is increased and ma pointw trodea preachesthat even reversein direction u toe of the anode. Thus range through which it-has anega;

t1 resistancezcharacteristic; that is, over which] he currentin the external circuitbetween-the cathode and the third electrode as the potential between the now a-constant potential is third-electrode, by means of current in theefie tentialis between the cathode -and theqd echa'r e -controllinig 81, the which leave the cathode varied, al circuit will that is,--ji'"'th'e is {made rame positive, the

be ijvariw aecofdingly member .8

bata third electrode 5.

electrode petential of yond this. the current will continue to decrease ere the potential of the thir elecin I we suchzalne that thc'device w opera as a nega ive resistan' ';'"will be ajconstant flow of "-ternal imuitu. If, however, a vafriable po t" em i flow of increase and if the member 6 is made more negative, the flow of electronswill decrease electrons to the, third electrodewill I and a small change in "the potential of the member 6 will be capable oi reducing a 'large chan e"- in the current tween the cathode an the third electrode. a in utilizing this, device for the reception oi wireless signals, waves which are received upon the antenna 9 are impressed upon the discharge controlling member 6 by an ,oscillatin circuit com. rising an inductance 10 w ich is couple to the antenna I inductance and a variable condenser "12.

I also provide in the external circuit be-.

meanspf tween cathode and third electrode a variable inductance l3 and a variable capacity 14: in

parallel. 'lhis'circuit may v telephonereceiver l5 s unted by'a variable condenser 16. In receiving s' als, by this system, the inductance 13 an may be so adjusted that the circuit is capable of oscillating at a frequency equal to that of the received signals. The value of the negative resistance is adjusted to such a point that the circuit is near a ointiof in-- stahility or a point where osci begin. When the potential of the member 6 is varied by received oscillations, the value of the negative resistance -sufiiciently so that the circuit will start'oscillatin Under these conditions the ainplification asymetric and thdresulting current will 'op sired indication. Without include, the usual ations. will will be changed of the received signals will he capacity 14:

the circuit would tendto produce oscillations of an undesirable audio. frequency. condenser 16, however, may as'to prevent the setting up oi audio frequency oscillations or may he so adjuated'a's to produce audio frequency .a froquency equal to the group frequency of the incoming waves. The final adyustments of the system may conveniently beinade varying the value of the ne varying the temperature Q in case the. system receivin adjust gative resistance continuous waves, itmay.

that continuous from that 'f. the received waves. The two sets ofosci ations .duce beats inthe telephone receiver 15;

order to. secure the highest degree of amplification in the symem thepositivei resistance of .tiv'e resistance.

in the arrangement shown in it ifthe negative resistance .oompenmtes orxthe lossesin th between; ca

This. he so adjusted oscillations {of or the cathode 2.

described is used for be so oscillations will be produced of a frequency slightlydiderent above described, v the circuit should v he-app roximately equal in value to thenega 'll then combine to pmgenitive resistance of the circuit. a t ode and third electrode. In"

the; odification shown in Fig. 2 l have-in,-

,dicated means for also for the losses in the resonant receiving circuit and the, antenna. In this case-the discharge con- ,muount of energy thus trans trolling .member 6, instead of being connected directly to the cathode 3, is connected to a suitably selected point 17 in the re sistanc 18 which is in series with the negameans of this resistance coupling'ener is-fed back from the negative resistance circuit to the resonant receiving circuit and by properly adjusting the oint 17, the

made suflicient to compensate for the losses in .the receiving circuit and in the antenna without producing oscillations.

A battery 19, ma'y be included in this circuit in order to adjust thenormal potential of the mem: her 6 to a valueat which it will operate most efliciently. Under these circumstances, the antenna coupling ma be as close and 7 its resistance as lar'e as esired.

WhileIKI have il ustratedand described only two modifications of m invention, it is by no means limited to t e precise ciroeuit arrangements shown as many modifi-' cations in-the connections may be made without departing from the'scope ofmy invention, as set forth in the ap ended claims.

What I claimlas new. and esire to secure by LettersPatent. of the United States, is

"1. The combination in a wireless receiving system of an electron discharge device *tpntmlling member inclosed in com rising anelectron emitting cathode, an ano e, a third electrode and a! discharge an evacuated receptaclejsources oipote'ntial a plied to said electrodes of such values that t e device has a ne tive resistance between cathodejand thir electrode which varies inversely as the potential applied to, the dis charge controllm member, and means for I v applym recelv c controlli r'r'g memben" v I com rising an electronlemitting cathode, an a third electrodef and} a discharge an) e, v. controlling member lnclosed m an evacuated waves to-the discharge- 2. The combinationin a wireless receiving system of an electroncdischarge device receptacle, sources of potential applied to said electrodes of such valuesthat the. de-

- Vi08 'hfiS"' a negative f resistance betweenv cathode and thir 'lectro e which varies inversely asthe'lpgtential applied to the dis- ;ccha'rge Ivcontrol g member, means fomaperred may be quency.

plying received waves to the' discharge controlling member and capacity and induc-- tance connected in said external circuit and so adjusted that the circuit is resonant to a desired radio frequency.

3. The combination in a wireless receiving system of an electron discharge device comprisin an electron emitting cathode, an aim e, a third electrode and a discharge controllin r member inclosed in an evacuated reccpt-ac e, sources of potential applied to said electrodes of such values that the device has a negative resistance between cathode-and thlrdelectrode whlch varles inversely as the.

potential applied to the discharge controlling "member,. mea-ns for applying received waves to the discharge controlling member,

a telephone receiver in said external circuit and a capacity shunting said receiver and haring a value so related to the inductance ,of the receiver that the circuit is resonant to a desired audio frequency.

4. The combination in awireless receiving system of an electron discharge device com prising'an electron emitting cathode, an anode, a third electrode and a discharge controlling member inclosed in an evacuated receptacle, sources of potential applied -,to said electrodes of such. values that the device has a negative resistance between cathoderand third electrode which varies" inversely as the potential applied to the discharge controlling member, means for applying received wavestothe discharge controlling member, atelephone receiver in said external circuit and a ca acity shunting said receiver andhavnig a -va u'e so related to the inductance of the receiver that the circuit is I resonant to a desired audio frequency, and capacity-and inductance connected in said external circuit and so adjusted that the circuit'isresonant to a desired-radio fre- 5. The combination in a. wireless receiving system of an electrom discharge device comprisingan electron emitting cathode, an

anode, a third electrode and a discharge controlling member inclosed in an evacuated receptacle, sources of potential applied to said electrodes of such value that the device has a negative resistance between cathode and" third electrode which varies inversely as the potential applied to the discharge controling member,'.mean for applying received waves tothe discharge controlling member and ca acity and inductance. connected in said e rnal radio frequency oscillations of a frequency slightly different from thatof the received oscillations will be generated in said circuit during the operation of the 6. The'comliination in a wireless receiving system of an antenna, an electron dischar c evice comprising an electron emitting ea o'de, an anode, a third electrode and a discircuit and so adjusted that v evacuated onan't circuit J jmember, and

charge controlling inember 4 inclosed -reee1mtac1e, sourcw ot applied to said electrodes. of sue values that the dericehas'e negetiveiresistahce between cathode and third electrode which lied to raries imgei'sely as the poteintiel app the discharge controlling member, a res-.

associated with said ontcnnn and: with said discharge controlling memher for impressing received waves lip on sendfor transferring from means the first mentioned circuit to the resonent an erecdttted .agph'ed to s'md electrodes of such v' uesthet fee circuit a suflicient emonnt of errergy to cornpensate for the losses 1n that circuit and m ,the antenna. C

. Thecombinatioh iii a wireles receivsystem of 'an e device has a; negative resistance between cathode and. tiersely ms charge controlling member, e "resonant circuit associated with seid entenne endmfith' said diecherge controlling "member for mnponseid member,

preming received weir end-, resistance coupling'gbete een the two m n tentiel :m node, at third electrode and a osed 1ntrve resistance resonant circuit;

third electrode which varies in-. the potential applied to the dis-.

- my hand this deyof Month,

meme? from" the circuits for transferring eneir v negative. resistance circuit to e monent circuit to compensate for the circuit and in the antenna;

8. The combination in a system ,of an antenna, an electron diachar device comp'risin ode, en'anode, a charge controlling member evacuated receptacle, sources of in that third electrode and e in'closed in an otentiel t c device has a negative resistance between cathode and third electrode which varies inversely as the potential applied to the dis charge controlling member, a resonant circnitv associated with said antenna and with said discharge controlling member for impressing rece ved waves upon posltlve reslstmnce in end. a connection from said to a pointin' seidl resist: so chosen that energy ance, said 'poi'nti be ng will he transferred irom the-negative N31853: once eircuit'tothe resonant circuit to com- "pensetefor 7 he the antenne.

losses in that circuit and in hereunto set llnwitness whereof; I Vim-V5- t,

ion.

'wireless receiving I e an electron emitting cagidied to said electrodes of such we ues that said member, series with thenegw

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