US1620973A - Radio receiving circuit - Google Patents

Description

w. KAUFMAN RADiO RECEIVING CIRCUIT Filed Anril 14, 1923' m u M 0m March 15,3927.

March 15 1927.

w. KAUFMAN RADIO RECEIVING CIRCUIT Filed April 2 Sheets-Sheet 2 IN VEN TOR ATTORNEY b Patented Mar. 15, 1927; I v v I UNITED STATES- ATENT QFFICE.

V I v tor rarnnsom ivnw annsny. a fpmmomoawmqcm mq I Application filed April 14.19212. s ria norcsiess."

This invention relates to radio receiving the'usual grid condenser 6 which is preferapparatus and more particularly to a novel ably shunted by the resistanceelement' 7 circuit employed for the reception'of radio and-thence to the filam'ent8of the audion 5, communication, and :has for its object the through the coil9','which is inductively. and

provision of a circuit which is simple in variably coupled with the @112 in the pristructure and schematic layout, eflicient in mary circuit. The plate electrode 10 of operation and which in operation has dcaudion 5 is'connected to'thegrid'electrode 4, cided advantages over other circuits forsimpreferably at a "point between the grid conilar purposes. denser 6 and the secondary coil 9. This con- 10 A further object of the invention isto nection is made preferably through a con provide acircuit which with but few'parts denser "1 2, and a high resistance path 13 is'simple in operation and highly efficient in is provided between the plate and grid selectivity. a electrodes. A variable tap connection-14 is Further objects of the invention Will 2113- provided for theinduct'ance coil 11, which 15 pear more fully herein. I r tap connectionhastwo'paths,oneto ground he invention consists'substantially in the 3 and the other through telephone receivers construction,combination, location and rela- 15, space currentsource 16, to filament 8 of tive-arrangementof parts, all as will be more audion 5. If desired, and as shown, the fully hereinafterjset forth, as shown bythe telephone receivers 15may'be shunted by a" c panying drawings and finally pointed condenser 17 The primary and secondary out in the appended claims. A circuits; in accordance with my inventionare Referring to the drawings: f p ,1' .f "connected througha variable capacity 18, as I Fig. 1 is aschematic view ofa circuit em shown. In Fig. 2 -tl1e schematicarrangebodying my invention. ment isslightly modified. I

. 25 Fig. 2 is a similar view ofa slightly .modi In this arrangement the tap coiinection 14 fied arrangement employing the circuitof is, as before, provided with twopaths, one my invention. I I j of-which leadsto the aerial land the other The same part is designatedby the same through the variable inductance 2 to the reference character wherever it occurs. ground 3 and the telephone receivers 15, 30 throughoutthe severalview sfi f" either with or 'without the shunting con- It is among the special purposes of my denser thereabout, and connected'between"the present invention to provide an electrical primary circuit and the secondary circuit, circuit and inethod of operation or a radio i. e., between the filament electrode and receiving system and apparatus for obtainground. The'filament electrode 8 is lighted 35 ing maximum amplification of the received in theusu'al' well-known manner from'a cursignal impulses by means of certain modi rent" source 2t) through a variable resi'stficationand alteration'of the ordinaryauance'Q/l, g f dion detector and amplifier circuits, and While I am not prepared at this time thereby obtain results" with a single tube to give a full and "complete scientific or 1 whichv wou'ldjbe impossible in accordance analytical explanation of the operation or 9.9

with the systems now known without addithis circuit, I do not desiretobe'lim'ited to or tional tubes or stages of amplification. bound' by any theoretical consideration Referring to Fig.1, which illustrates a thereof, hejoper'ation ofwhichcircuit-obsimple schematic wiring arrangement e1n- 'tains thefollowing results? bodying myinvention, reference character In the firstplace, the circuit is extremely 5 1 designates the antenna vwhichis connected eflicient' for the receptionoftelephone sigthrough the variable inductance tubeto the nails, and when being operated to receive earth 3; The secondary circuit of the'retelephone signals reception of'spark signals ceiving system includes the grid electrode is for all practical purposes eliminated. and

50 A of the audion 5 which is connected through thereby eliminates the disadvantageous-ef- 9 tion of continuous wave signals.

fects of damp wave signaling on the recep- By controlling the variable elements-namely, the tap connection 14 of the inductance 11 of the plate circuit-the tap connection on the primary inductance 2 and the condenser 18 bridged between the primary and secondary circuits, I have-found that it, is possible to obtain great selectivity and completely tune out adjacent stationsoperatin'g on a-=definite*- wave length and receive a distant station operating on the same wave length without interference. I have also found the system to be especially adapted" for use in reception of continuousiwave signals and-the. audion 5 placed in'a state of oscillation generation at a controllable. frequency whereby if the beat notes method ofreception isrbeingemployedv the 'pitch or frequency. of. the beat notemay be readily controlled.

It will "be observed-that in each instance the circuit consists of a combined detector circuit and amplifier circuit; e. g referring to Fig. 1, the 'detectorcircuit comprises the grid electrode l, the grid leak 13, condenser 12,'the lower portion of the inductance 11, tap connection 14,- ground 3, tuning. condenser 18 and filament electrode 8, with the usual plate circuit 10, inductance 11, telephone receivers 15 andB current source '16. The amplifier circuit. will be apparent as follows: v

The gridfilament circuit consists of grid electrode 4, resistance 13, inductance 9,, to the filament electrode 8. The plate circuit in thisinstance comprises the plateelectro'de 10, a portion of the inductance 11, telephone receivers 15, and the B battery source 16 to the filament- 8.

It may be that the foregoing constitutes one explanation for the efiiciencyof the drcuit employed but, as above stated, I I. do not desire to be limited or restricted thereto as I desire to have the foregoingydescription recorded in the illustrative sense rather than in the limiting. sense. I

In the practical operation of the system embodying my. invention certain rules of adjustment shouldpreferably beobserved to obtain theamaximun results. course, these rules would differ somewhat inrac'cordance withthe type of-signal (i. e., telephone or continuous wave) which is to be received and the degree of selectivity desired.

Where radio telephone reception is desired, it is necessary to keepthe system from oscillating, whereas in cont1nuouswavesig= nal reception it is necessaryv to produce oscillation slightly above orbelow the fre quency of the-receiver signals, [in order.- to obtain beats of an audible frequency in accordance with the Heterodyne method "of reception.

It may be generally stated, however, that the frequency of the secondary circuit is 'bination with an audion, having a grid-filathe use tliereof fin connection with wireless telephone or telegraph transmission or rec'eption" as distinguished from radio frequency signaling. systems, for it will be readily apparentto' those skilled in the art that features hereof may be employed in con-' nection wired wireless or carrier current signaling. systempr any other type of electrical .sign'aling system .at' present employed'in connection with vacuum tubes.

Many further modifications and changes in details will readily be apparent" to those skilled in the art without dep artingf'rom the spirit andscope of my invention as defined in the claims,.but having now set forth the objects and vnature'of my invention andhaving shown and described '-s tructures embodying the principles thereof, what I claim as new and useful and of my own invention, and desire to secure by Letters Patent is:

1. In a radio 'signaling system, the combination with an audion, having a grid filament circuit, of a circuit including an inductance coil connecting. the plate electrode oflthe audion-with thegr'id electrode thereof,

and a'variable connection between said coil and the filament electrode of the audionindependently of said grid electrode connec- I tion. a

, 2. Ina radio signaling. system, the com- 'bination'with an audion, having grid-filament circuit and a direct current plate-fila ment circuit, of an inductance included in. the plate-filament circuit, said direct current plate filament circuit having a'tap connection from said inductance to ground, and a telephone receiver and voltage source, connected between said tap connect-ion a'ndfthe filament electrode of said audion. 8. In a radio signaling syste1n,the coniment circuit, of a circuit including an inductance coil connecting. tlie plate electrode of the audion with the grid'electrojde thereof,

a variable'connection between'said co'illand ground, and a telephone receiver and current source bridged between said connection and the 'filament'electrode of' said audion,

said bridged connection having no portion. thereof'incommon with the grid plat'e'circuit.

4." In a radio signalingsystem, an antennaearth circuit having an inductance therein, and an audion anditscircuits'with the gridfilament circuit thereof conductively associated with said antenna-earth circuit and the filament electrode of said audion, said grid-filament circuit, and a tuning condenser connection including a telephone receiver. connected between said antenna earth circuit 5. In a radio signaling system, the comand said grid-filament circuit. 10 bination with an audion having grid-fila- In testimony whereof I have hereunto set 5 ment and plate-filament and grid-plate cir-- my hand on this 10th day of April A. D., cuits, of an antenna earth system including 1923. an inductance inductively coupled with the WOLFF KAUFMAN;

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