‘June 13, 1933,. ‘ “mm 1,914,219. SIGNALING SYSTEM ‘ Filed Jan. 3, 1927 ?lVeiovg/numfa‘el PHtaheontds lnteqsz'ty of Impressed High Frequency [mpu/ses ' Inventor‘: Dewey TS Lmonds. M142 Hus Attop ney. 1,914,219 Patented June 13, 1933 ‘ pullrsn» STATES PATENT OFFICE NEW YORK, ASSIGNOR '1‘0 GENERAL ELECTRIC_ -=.: paw-n! r-s-mouns, orscnnnnorany, - comrarw,_a oom'ona'rxon or NEW YORK . ,~ ' . sresmmno sYs'r-EM- v Application ?led Ianuary a, 1927. Serial in. 158,454. "My invention: relates to signaling systems and-particularly to systems for the reception of high frequency signaling currents, and h'a's'for ‘its purpose to provide a signaling sys mentalities having moving ‘parts introduce disturbances and time delay in the operation of the system which in turn result in unde sirable elfects upon the receiver. purpose of my invention is to provide ‘ tern such-that the intensity of the received anThe apparatus of the type mentioned, which signal‘ will be automatically maintained at or will be entirely automatic in its operation; bel'ol'wa predetermined, level. _ i It is ‘well i-known'that when the receiving and which will be simple in its circuit con and entirely electrical‘ in its opera-v circuits of a high frequency signaling system struction tion. By the provision of such‘an apparatus 6'05 it have heen'adjusted to produce great enough I have found that the disadvantage of pre4 ampli?cation for reception of signals ‘from a viousiapparatus referred to above may be . distant station the signals from a near by station will be received in much greater vol— largely eliminated. ume than is desired. Likewise, it may re pli?cation of the signaling circuit in direct ct"; it? sult-that-during‘ reception from a single sta tion'the transmission characteristics of the media over'which the signals are being trans mitted may vary'causing the intensity of the received signals to ?uctuate thereby necessi tating frequent readjustment of the receiv ing ‘circuit to compensate for the variations v v " By my invention I vary the degree of am electrical response to the intensity of the high frequency impulses which are impressed upon the system. . The novel features which I believe to he characteristic of my invention are set forth with particularity in the appended claims. both as to its in the transmission media and to maintain My invention itself, however, operation will. organization and method of the1 desired‘ volume level of the received sig best be understood by reference to the follow description taken in connection with‘the Means have heretofore been provided for ing accompanying drawing, in which Fig. 1 illus automatically controlling the‘ transmission level in high frequency systems. These means trates diagrammatically one form of my in Fig. 2 presents curves illustrating have usually involved relays which operate vention; responsively to the intensity of the received its operation; and in which Fig. 3 illustrates a modi?cation of the circuit shown in ‘Figt 1. ‘to high frequency impulses to control the power With reference to Fig. 1, 1 illustrates a na ‘ ' circuit to a motor which affects appropriate .35 leading to the usual antenna or wire adj ustinents'in the transmission circuit. Oth circuit line depending upon the particular applica ers have involved relays which operate re for which the system is employed. sponsively to the intensity of pilot frequen tion cies transmitted over the same transmission and 3 represent the usual radio frequency am pli?ers of the receiving circuit, ampli?er 2 being supplied ‘with energy from the input volved relays which operate responsively to media as the signal, while still others have in ’ - changes in current passed through pilot wires transformer 4 and input circuit 5 which is’ which are subjected to the same transmission connected to the control electrode 01' grid 6 conditions as the media. over which the de ofthe ampli?er 2. Likewise, energy is sup from the output circuit 7 of the electron sired signal is bein gtransmitted. Still other plied discharge device 2 through the transformer means have been provided for manually con 8, and tuned circuit 9 to the control electrode trolling the'transmission level. or grid 10 of the ampli?er 3., 11 represents All of‘ these systems have inherent disad ‘i vantages in that they either require the pres the detector of the usual receiving circuit. ence of a skilled operatoror are complicated This detector receives its energy from the outin their 'circult construction - necessitating put circuit 12 of the amplifier‘ 3 through the ' the use ofv auxillary carr1er current genera transformer 13 and input circuit 14. Audio tors, pilot wires and the like. Furthermore, - frequency currents from the detector are sup 100 the use ofrelays, motors and other instru plied from the output circuit 15 through -% 1,914,219 transformer 16 to the audio ampli?er 17 current which flows in the output circuit of where they are ampli?ed and impressed upon the detector 11 flows through the resistance the head phones 18. While the ampli?ers 2 28. Since this current varies in response to and 3. and the detector 11 are shown as of '5 the electron discharge type, it will be appar cut that any type of ampli?er or detector may be used. Since the circuit connections of the ampli?ers and detector, as thus far described the intensity of the high frequency impulses which are impressed upon the detector 11, the 70 potential upon the resistance 28 will corre spondingly vary. I utilize this potential upon the resistance 28 as a means for con are merely those of a common receiving cir trolling the ampli?cation of the radio am cuit,-only so much detail is given as is neces— pli?ers 2 and 3. To this end the ampli?er 75 sary to an understanding of my invention. 43 having an anode 44, a cathode 45 and a 15 Thevcathodes 19, 20, 21 and 22 of the radio control electrode or grid 46 is employed. A ampli?ers 2 and 3, detector 11 and audio am— suitable source of potential is impressed upon pli?er 17 are shown connected to a circuit 23 the control electrode 46 with respect to the which is energized through resistance 25 cathode 45 through an input circuit including from a suitable source ofpotential 26. Suit 80 the cathode 45, cathode conductors 23, con able high potential is supplied to the output ductor 24, source of potential 27, resistance circuit of the detector 11 from the high po 28 which constitutes a variable source of o tential source 27 through a circuit as fol tential, conductor 29, adjustable tap 47, t at ' portion of the resistance 48 which is between 85 ac lows: cathode 21, cathode conductors 23, con ductor 24, source of potential 27, resistance the adjustable tap 47 and adjustable tap 49, 28, conductor 29, primary winding 30 of the adjustable tap 49, that portion of the source . transformer 16 to the anode of the detector of potential 50 which is»,between the contact 11. The source ‘of potential 27 which com 49 and conductor 51, conductor 51 to the con prises the usual B battery of a receiving cir trol electrode 46. A portion of the source of cuit is provided with an adjustable tap 31 potential 50 is closed circuited through the 90 from which a suitable potential may be sup-v adjustable tap 49, resistance 48‘ and conductor plied through conductor 32 and conductor 52. The purpose of this arrangement will 80 85 33' to the anode of the ampli?er 2 through the primary winding 33 of the transformer 8, to the anode of the ampli?er 3 through the primary winding 34 of the transformer be seen later. A suitable potential is im pressed upon the anode 44 of the ampli?er 43 with respect to the cathode 45 through an 95 output circuit including the cathode 45, 13- and to the anode of the ampli?er 17 cathode conductors 23, conductor 24, that por through the head phones 18. Likewise, a tion of the source of potential 27 which is be-4 suitable source of potential is impressed upon tween the conductor 24 and the adjustable tap the control circuits of the ampli?ers 2 and 3 24’, adjustable tap 24’, resistance 35, conduc with respect to their cathodes 19 and 20 tor 53 to the anode 44. For the purpose of preventing alternating ductors 23, conductor 24, that portion of the ' current from being supplied from the output 100 through a circuit as follows: cathode con source of potential 27 which is between the of detector 11 to the input of the ampli?ers 105 ‘conductor 24 and the adjustable tap 24’, ad 2 and 3 through the volume control circuits justable tap 24', resistance 35, conductor 36, the condenser 55 is inserted between the con source of potential 37, conductor 38, thence ductor 29 and the cathode conductors 23 and throu h conductor 39, and a portion 40 of the condenser 56 between the conductor 41 and w 'secon ary winding of the transformer 8 to cathode conductor 23. The operation of the circuit is as follows: thecontrol electrode 10 of the ampli?er 3, and through the conductor 41 and a portion During normal operation when the volume of 42 of the secondary winding of the trans the received signal is at or below a predeter 110 former 4 to the control element 6 of the am mined level, current will be ?owing in the w pli?er 2. It will be seen that the source of anode circuit of the detector 11 and through 115 potential 37 is in series with that portion of the resistance 28. The sum of the potentials \ the source of potential 27 which is between in the control circuit of the ampli?er 43 which 55 50 the conductor 24 and the adjustable tap 24'. includes the source of potential 27, resistance Hence the e?ective potential on the control 28, a portion of resistance 48, and that por elements 6 and 10 of the ampli?ers 2 and 3 tion of the source of potential 50 which is with respect to their respective cathodes will ‘between the adjustable contact 49 and the be determined by the sum of these two sources conductor 51 will be such that a strong nega of potential and by the potential'on resist tive potential will ‘be impressed upon the ance 35. This biasing potential is normally electrode 46: This being the case, no current such that these devices operate principally will ?ow in the anode circuit of the ampli?er as ampli?ers, and with substantially a mini mum of detecting e?ect. - As already explained the resistance 28 is connected .in a circuit including the output 120 125 ' 43 and asa result no voltage will appear upon the resistance 35. The sum of the potential 37 and that portion of the source of potential 27 , which is between the adjustable contact '65 circuit of the detector 11. Hence the direct 24' and the conductor 24, is such that the am 130 3 1,914,219 I (.1 pli?cation of the ampli?ers 2 and 3 will be ume level will be unaffected. If it be desired increase the volume level of the received, a maximum and reception will take place in to signal, then the contacts 47 and 49 maybe theNow usual assume way. that ' - a signal of 'higher inten so adjusted that a stronger negative potential sity is impressed upon the receiving system.’ will be ‘impressed upon the grid 46. With Then the voltage on the resistance 28 will di such an "adjustment a greater‘ volume must be 28 before the minish. and the source of potential 27 will impressed upon theonresistance the electrode 46 will be ‘negative potential become effective upon the electrode 46 cans ing it to assume a less negative or even posi su?ieiently diminished to permitthe ?ow of current through the anode circuit of the am tive potential depending upon the intensity pli?er 43.’ Hence, only intensities above those of the received high frequency impulses. represented by the curve 3 will be diminished Hence, current will ?ow in the anode circuit and reception will take place on‘ the curve 3. of the ampli?er 43 and through the resist ance 35 causing a voltage to appear upon By adjusting either of the contacts 47 or 49 80 in the opposite direction reception can be this resistance having the polarity indicated made to take place upon the cirve 4. in the drawing. ‘Since- thisvoltage is in se lVith the potentiometer contact 47 adjusted ries with the. source of potential 37 in the impress any desired bias on the grid of the . circuit of the control elements of the ampli? to direct current ampli?er,v current starts to ers 2 and 3, the potential upon the control build up in the anode circit of the ampli?er elements will be increased in a negative direc- 7 a corresponding critical value of input ra tion, thereby correspondingly diminishing at the ampli?cation of the circuit and thereby dio frequency voltage to the detector. the radio frequency input voltage to the de diminishing the intensity of the signals at tector increases beyond this critical value the the , receiver. ' current in the direct current ampli?er in 90 This operation may best be understood by creases extremely rapidly, and in a substan reference to Fig. 2 in which I have plotted tially linear relation to the radio frequency‘ the intensity of the high frequency impulses voltage. In this way su?icient control which are impressed upon the receiving cir input of the is had to maintain the cuit as abscissae and the intensity of the sig— volume ampli?cation of signal at the head hones within nal at the head phones for any given percent age modulation-as ordinates- The curve 1 represents the operation of the circuit when (.0 95 a satisfactorily small range 0 variations in intensity. ' ' In Fig. 3 of the drawing 1 have shown a the potential upon the electrode 46 of the am modification of my invention in which the pli?er 43 is so strongly negative that no cur- ' ampli?er 46 hasbeen omitted. It will. be 100 rent flows through the anode circuit of this seen that in this case conductors 39 and 41 ampli?er or through the resistance 35. As are connected through the source of potential sume that it be desired to maintain the vol 37 and the resistance 48’, which have been ume of the received ‘signals at the head phones connected in parallel relation for purposes of at a level indicated by the curve 2. The con adjustable contact 54 and con 105 tacts 47 and 49 will be adjusted to impress ‘adjustment, a negative potential on the control electrode ductor 55 to the point on the resistance 28, > 43 such that no current will flow through the which is connected tothe output circuit of the detector 11. Hence, it will be seen that any resistance 35 until the high. frequency im ?uctuations in the potential of the resistance pulses impressed upon the detector are of 28 will be impressed directly upon the control 110 such volume as to produce a signal at the circuits of the amplifiers 2 and 3. An ar head phones corresponding to the level rep resented by the curve¢~2 at the given percent age modulation. Then for all high frequency intensities which produce'si-gnals below this level the amplification of the circuit will be rangement of this type may be preferable in on the curve 1. If the volume of the high fre pli?ers are- used, such that the adjustment is av circuit where only small adjustments are required as where the changes in the char acteristics of the transmission media are 115 at a maximum and reception will take place small, or in a circuit where a number of am quency impulses which are impressed upon effective upon a number of ampli?ers. This the detector 11 become so great as'to cause the arrangement effects a substantial economy in ‘120 volume of the received signal at the head the apparatus required. _While I have describedmy invention with phones toexceed the level represented by the particular reference to a common receiving curve 2 vthen the negative potential on the circuit employing a particular type of detec electrode 46 will be so diminished thatcur- ' rent will flow through the anode circuit of tor it will be apparent that it is not so limited 125 the ‘ampli?er 43, causing a diminution in the but rather that it may be employed in almost ampli?caiton of the ampli?ers 2 and 3. any. type of high frequency receiving system a contact volume of output is desired. Hence, all high frequency impulses which where in the embodiment shown I have produce signal intensities above the level 2 at Likewise, the given modulation will be diminished to employed a detector as the controlling tube .130 this level, whereas, intensities below this vol purely from considerations of economy in the 1,914,219 . apparatus since, obviously, any type of recti fying device may be em loyed as well. - in the output circuit of said detector, an elec— tron discharge device having an anode, a Furthermore, it will be apparent that the cathode and a grid, said resistance being con control device may be made to operate upon nected between said cathode and said grid, a ‘ “5 ampli?ers subsequent in the circuit to the con-7 second resistance connected between the an- 70 trolling tube 11 rather than prior to it as in ode and cathode whereby the potential on the embodiment shown and that such an ar said second resistance is dependent upon the rangement will have certain advantages such output current of said detector and means as results from the fact that it entirely elimi for varying the potential on said control ele~ 10 nates regeneration or any tendency to oscil ment in response to the potential on said sec 75 late. This also enables me to make condensers ond resistance thereby to control the ampli? 55 and 56 of very small capacity, thereby cation of said ampli?er. eliminating any time delay in the operation ‘ 2. The combination, in a receiving circuit ' of the device which may be produced by embodying an electron discharge ampli?er 1.5 the char ing of these condensers. However, having a control element, connections where— I have ound that with this arrangement by current having amplitude dependent upon greater difficulty is encountered in obtaining the characteristics of the transmission medi substantially horizontal characteristics as shown in Fig. 2 over a large range of in v 20. tensities of impressed high frequency im ’pulses,than is the case in the embodiment shown. It may thus be seen that I have provided a 80 um over which currents are received are sup plied to said ampli?er, means ,for rectifying a portion of said current thereby to produce a source of direct current potential which is 85 variable in response to the intensity of the ' received current, means for amplifying said volume control device which is simple in its direct current potential and for supplying the 25. circuit structure and its operation and which ampli?ed potential to the control element of does not require the attention of a skilled said ampli?er thereby to control the ampli? operator, which operates directly in response cation in response to the intensity of the re 90 ' " to the high frequency impulses which are im ceived current. pressed upon the circuit rather than in re 3. The combination in a signaling system, 30 sponse to changes in a pilot frequency which employing an electron discharge device hav- 95 is transmitted over the same media as the ing a grid, means for impressing a biasing received signal, or in response to current potential on said grid such that said device ?owing in pilot wires, which are subjected to operates principally as an ampli?er and with the same conditions as the media over which a minimum of detecting effect, means for sup plying current to be ampli?e to said grid, done heretofore. My invention has the fur a. second electron discharge de ice having an ther advantage that it is completely electrical anode circuit, a cathode and .a grid, means 35- the received signal is transmitted, as has been . 100' in its operation and does not. involve any for impressing a uni-directional biasing po mechanical moving parts, such as motors, re tentialon the grid of said second device such 40. lays and the like, which introduce undesir , that substantially no current ‘normally flows ‘ v able elfects in the operation of the system. in the anode circuit thereof, means for vary- -' Hence my device is practically instantaneous ing said uni-directional biasing potential on in its operation. My invention has a further the grid of said second device in response to advantage in that it involves but a small the intensity of the received current and to ‘45 amount of apparatus and that it may .be ap cause current to flow in the anode circuit 110 plied with facility and without great expense thereof when the intensity of received cur rent exceeds a predetermined value and means to any of the usual signaling circuits. While I have shown and described a speci?c embodiment of my invention, it will be ap 50. parent that it—is not limited to the particular embodiment shown but that many modi?ca tions in the circuit arrangements and instru mentalities employed \in carrying out my in vention may be made without departing from for controlling the potential on the grid of said ?rst device in response to the current in this anode circuit of said second device th'ere 115 by to regulate the simplification of said ?rst device. . l 4. In a high frequency receiving system, sound reproducing means, an electron dis 55.. the scope thereof as set forth in the appended charge device having a grid, means for im claims. - . 120 pressing high frequency potential on said What T'claim as new and desire, to-secure grid, means for impressing a biasing poten by Letters Patgit of the Unted States is :— tial on said grid such that said device oper 1. The combmation in a receiving circuit ates principally as an ampli?er of said high 60' employing an electron discharge ampli?er frequency current andwith a minimum of de 125 having a control element, a detector and con tecting effect, additional means comprising nections whereby current having amplitude an electron discharge detector for deriving dependent upon the characteristics of the audio frequency current from the ampli?ed transmission medium are supplied to said high frequency current and for supplying 65. ampli?er and detector, a resistance connected said current from said detector to the sound 130 1,914,219 reproducing means, and means including said‘ detector for varying the direct current poten tial upon the grid of said ?rst mentioned electron discharge device only when the high frequency input to said detector exceeds a predetermined value and then to vary said 5 ' 11. The combination with an audion, of means for biasing said audion by a direct current voltage, means for automatically va rying said bias voltage in accordance with the strength of an incoming signal, at least one 70 of said means comprising a rectifying system including an element having. a“ critical work direct current potential substantiallyl linearly ing voltage, and means where y/said critical with respect to variation in said igh fre quency input to said detector thereby to con v10 trol the ampli?cation of said electron dis charge device. - voltage may be adjusted. 12. In combination, an audion, an out ut 75 circuit therefor, means for suppressing ?YlC tuations in said output circuit due to varia ceiver of the type including a carrier wave tions in the strength of an incoming signal, said means comprising a rectifying system ampli?er, a detector and an audio frequency having a certain input voltage below‘ which 80 output circuit fed from said detector, the substantially no direct current output is ob method of automaticallyv reducing the effects tained and above which said direct current of varying signal strength which comprises 5. In the operation of a carrier wave re -15 20 amplifying the direct current potential devel oped in the plate circuit of the detector, and impressing the ampli?ed direct current po output rapidly rises and attains an approxi control the ampli?cation thereof. certain input voltage. mately linear relation with respect to the in-, tensity of the signal applied to the input of 85 tential upon said carrier wave ampli?er to ‘said detector, and means for adjusting said In witness whereof, I have hereto set my 6. In a carrier wave receiver, the combina hand this 31st day of December, 1926. tion with a carrier wave ampli?er, a detector . DEWEY T. 'SIMONDS. and an audio frequency output circuitfed from said detector, of an impedance in the plate 25 circuit of said detector, a direct current am pli?er connected ‘across said impedance, and circuit connections for impressing the ampli ?ed output of said direct current ampli?er 30 95 upon the carrier wave ampli?er to control the ampli?cation thereof. 7 . A carrier wave ampli?er of the vacuum tube type and including circuit elements for automatically impressing upon said ampli?er . . an ampli?cation-control voltage proportional 35 100V to received signal strength, characterized by the fact that said circuit elements include a direct current ampli?er. ‘ 8. In combination, an audion, an out ut circuit therefor, means for suppressing uc tuations in said out ut circiut due to varia 45 tions in the strengt of an incoming signal, said means comprising a rectifying system having a critical input voltage below which 105 110 substantially no direct-current out ut is ob tained, and means for adjusting said critical vo ta 9. 50 e. " ‘ ' 11 an electrical system, the combination ' with an audion .having input and output cir c-uits, of means for suppressing ?uctuations in said out at circuit due to variations in the 115 strength 0 an incoming signal in said input circuit, said means comprising a rectifying 55 system of the type having an approximately 120 ' linear relation between direct-current output and radio frequency input above a critical in put voltage, and means for varying the crit ical voltage of said rectifying system. 60 v10. In an electrical system, the combina 125 tion with an audion, of means energized by said audion for impressing va variable bias on said audion, said means having'a critical working voltage, and means for adjusting 85 said critical voltage‘. v ' ' 130
© Copyright 2024