Sept. v17, 1929. I 1,728,816’ . W.'C. WHITE SIGNALING SYSTEM Fil'ed Jan ._ 19. 1924 Vnn. by Tim/?g WM .vmAWorm(b =mjm‘ e. Hn "w m+ 1,728,816 Patented Sept. 17, 1929 UNITED STATES PATENT OFFICE WILLIAM C. WHITE, 0F SCHENECTADY, NEW YORK, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK ‘SIGNALING SYSTEM Application ?led January 19, 1824. Serial 1T0. 887,861. My present invent-ion relates to signaling vice 1. Oscillations produced in this oscil systems, and more particularly 1.012121151111171 latin circuit are supplied by means of a’ 7 ting apparatus for high frequency signallng. coup ing coil 16 to the‘ grid circuit of device The~object of my invention is to provide 2, this grid circuit including a grid con =5 improvements in apparatus for producing denser 1 , a by-pass condenser 18, and a se and amplifying high frequency currents and ries resistance 19. The high frequency os utilizing- such currents for signalmg‘pur cillations thus supplied to the grid circuit poses, such for example as radio telegraphy. 55 of device 2 are amp l?ed and supplied through The novel features which I believe to be a blocking condenser 20 to a storage circuit I. characteristic of my invention are set forth made up of the variable inductance 21 and with particularity in the appended clainis; condenser 22. This storage circuit is cou my invention itself, however, both as to its pled in the manner indicated to loading coil organization and‘ method of operation will 23 on the antenna 3. This antenna may be best be understood by reference to the fol of the multiple tuned type havin as many ll lowing description taken in connection with separate loa ing coils as desire . In the the accompanying drawing in which I have present case only two, 23 and 24 are shown. shown dia ammatically a cii‘cuitorganrza The current for heating cathodes 4 of the tion where y my invention may be carried two devices is furnished through transform 65 into e?ect. _ ers 26, 27 from an alternating current source I have indicated in.the drawin ,a radio connected to supply mains 25. The grid con 70 transmitting system comprising a t rec-elec denser 13 in the rid circuit of device 1 is trode electron discharge device 1 of the shunted by a cholgring inductance 28 and a 25 30 thermionic type, which is .employed for the urpose of producing high frequency OSCll lhtions, and a second device 2 of the same type which is employed for amplifying the oscillations roduced by the ?rst device, and means of a key 32 conn'wted in a circuit with grid 6. Current for the operation of the comparatively small the system thus far de- ‘ resistance 29, which are connected in se ries with a relay device 30, this relay device being connected in shunt to the keymg con 75 denser 31. The relay 30 may be actuated by then supplying the ampli?ed oscillations to any suitable source of power supplied by the transmitting antenna 3.. Devices 1 and 2 mains 33 for operating the relay 30. each comprise the usualcathode 4, anode 5 and When the power output.of an oscillator is 80 anode or plate circuits of the two devlces is scribed is quite satisfactory. When the re 35 40 45 60 furnished by a ‘source of high potential di rect current connected to the supply conduc tors 7 and 8. The positive terminal of the direct current supply source is connected to lay 30 is closed oscillations will be produced and as soon as the relay is opened a negative charge of su?icient value to interrupt the pro duction of oscillations will be built up on the the anodes 5 through choking inductances grid by reason of the presence of condensers 9 and 10, which revent the high frequency 13 and 31. As soon as oscillations are currents produced, in the system from ?owing stopped the negative charge on the id tends through the source of supply. The anode 5 to leak off and there is a tendency or the de of device 1 is connected through a blocking condenser 11 and a portion of the inductance 12 to the cathode 4. The grid 6 of device 1 is connected through a grid condenser 13 and a portion 14 of the inductance 12, to the cathode 4. A ortion of the inductance 12 vice to start oscillating again. As soon as oscillations start again, the negative charge on the grid again will be built up and the pro duction of oscillations will be interrupted. The length of time between these intermit tent oscillations depends on the leakage of the _ is also shunted by a condenser 15. This con grid charge which in turn depends upon the denser in connection with the coil 12 forms insulation of the grid circuit and of the tube. an oscillating circuit which determines the With low power devices these intermittent frequency of the oscillations produced by de oscillations are not of su?icient intensity to 100 2 1,728,816 be objectionable. but when considerable power a negative biasing voltage is obtained which used this effect is objectionable because it is twice that of the alternating current volt causes interference. The magnitude of these age of the secondary 42 and this total voltage oscillations is a function of the tube efficiency, is divided between the two recti?ers 43 and 44, the higher the ciiiciency the greater the mag which are connected in series. The use of the nitude because of the\fact that a higher ini tial voltage is required to start oscillations. recti?ers for furnishing the biasing voltage ' for the grid also has a particular advantage To 0\ crcomc this disadvantage I have pro— in the case of the power ampli?er tube. vidwl a rut-ans for furnishing a negative bias When the key 32 is opened and the production upon the grid 6 of oscillator 1, which is ef fective, as soon as relay 3O is'opencd. negative bias is provided by means of an al 15 20 25 40 45 50 in a positive direction and this impulse may ternating current which is impressed upon be sufficient to reverse the potential of the the grid circuit by means of a transformer 34. grid and produce dynatron action. The rec The portion 35 of the secondary turns of ti?ers 43 and 44 however, minimize the ampli 80 transformer 34 is connected in series with the tude of the positive grid potential and there thermionic recti?er 36, the anode 37 of which fore tend to prevent the occurrence of dyna is connected through a high resistance 38 to tron action. While I have shown and described only one one side of the keying condenser 31. The smoothing condenser 39 is provided for embodiment of my invention, it will be‘ ap-' smoothing out the variations in the alternat parent that many modi?cations in the circuit ing potential thus applied to the grid, and in arrangements employed may be made with suring the proper operation \of the rectifier. out departing from the scope of my invention The cathode 40 of the recti?er 36 may be as set forth in the appended claims. heated by means of alternating current sup What I claim as new and desire to secure 90 plied by the turns 41 of the secondary of by Letters Patent of the United States, is: transformer‘ 34. It will be observed that when the relay 30 is closed this source of bias ing potential is short circuited. The high re sistance 38 is provided to prevent the ?ow of excessive current through the recti?er 36 dur 35 of oscillations by oscillator 1 is interrupted This the grid 6 of ampli?er 2 is given an impulse ing periods when the key 32 is closed. This method of keying is also preferable to those in which oscillatlons are interrupted by the building up of a negative charge on the grid 1. The combination with an electron dis charge‘ device having a cathode, an anode, and a grid, of means for impressing a nega tive potential upon the grid of said device comprising a source of alternating current 95 and a rectifying device having asymmetric conductivity serially connected in a circuit between said cathode and said grid, the grid of said electron discharge device being sub through a grid condenser as both the starting stantially insulated from the cathode with and the stopping of oscillations are more respect to direct current except through said abrupt. This gives a cleaner signal and also rectifying device and the space within said discharge device whereby said rectifying de permits of higher speed signaling, When the ke 32 is closed the potential of vice is e?’ective to prevent a reversal in di 100 105 rection- of the current ?ow in the grid circuit. 2. The combination with an electron dis The resulting rush the ‘grid of oscillator 1 is suddenly raised from a negative value to zero. of current due to this change has a tendency to make the grid positive and cause a sudden rush of plate current. This has a tendency to make the grid still more positive by rea son of dynatron action, and as a result the tube 1 may draw so much current that it will be destroyed. The use of the series resistance charge device having a cathode, an anode and a grid and having grid and anode cir cuits, of means for supplying signal repre senting high frequency oscillations from the anode circuit to a transmission circuit, and means for impressing a negative potential upon the grid comprising a low frequency 29 eliminates this difficulty by limiting the source of alternating current, and a rectify ing device having asymmetric conductivity ?rst rush of grid current. 115 A biasing potential for the grid of ampli serially connected in the grid circuit, the grid 55 ?er 2 is also provided from the alternating of said electron discharge device being sub’ current source. Transformer 41, the pri stantially insulated from the cathode with inary of which is connected to the alternating respect to direct current exceptv through said current source has its secondary 42 connected rectifying device and the space within said to thermionic recti?ers 43 and ‘44. One end discharge device whereby said rectifying de of the secondary 42 is connected to the anode vice is effective to prevent a reversal in direc of recti?er 44 and to the cathode of recti?er. tion of the current flow in the grid circuit. 3. The combination with an electrondis 43 while the other end of the secondary 42 is connected through condensers 45 to the‘ charge device having a cathode, an anode and cathode of recti?er 44 and to the anode of a grid, of a circuit between cathode and grid recti?er 43. 65 The anode of recti?er 43 is con 120 which includes a series condenser, a circuit nected to the grid 6 of ampli?er 2 through a in shunt tosaid condenser which includes a choking inductance 46. By this arrangement resistance and a. second condenser, and a 130 1,728,816 source of alternating current and a recti?er connected in shunt to said second condenser. 4. The combination with an electron dis charge device having a cathode, an anode and a grid, of a circuit between cathode and grid which includes a series condenser, a circuit in shunt to said condenser which includes a resistance and a second condenser, and a source of alternating current, a high resist 75 ance, and a recti?er connected in shunt to said second condenser. 5. The combination with an electron dis charge device having a cathode, an anode and a id, of a circuit between cathode and grid 80 w 'ch includes a series condenser, a circuit in shunt to said condenser which includes‘ a re sistance and a second condenser, a source of alternating current and a recti?er connected in shunt to said condenser, and a signaling 85 device connected in shunt to said second con denser. In witness whereof, I have hereunto set my hand this 18th da of January, 1924. _ 90 95 1'00 105 110 115 120 125 130 ILLIAM C. WHITE.
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