US2113263A - Electrical transmission system - Google Patents

Description

April 5, 1933- J. G. ACEVES 2,113,263

ELECTRICAL TRANSMISSION SYSTEM Original Filed April 28, 1951 2 Sheets-Sheet 1 Fig.1.'

i 11 3 10 5 1i 6 1 6 I 15 8 V J. 6 Ac'ez/eS INVENTOR ATTORNEYS April 1938. J. G. ACEVES 2,113,263

ELECTRICAL TRANSMISSION SYSTEM Original Filed April 28, 1931 2 Sheets-Sheet 2 J /lceves INVENTOR ATTORNEYS Patented Apr. 5, 1938 UNITED STATES PATENT OFFICE ELECTRICAL TRANSMISSION SYSTEM Julius Gourgues Aceves, New York, N. Y., assign- -or to Revelation Patents Holding Company, New York, N. Y., acorporation of Delaware Application April 28, 1931, Serial No. 533,396 Renewed February 3, 1934 31 Claims.

current variations of larger amplitude without appreciable distortion.

Another object of the invention is to provide an improved method of coupling a series of electron discharge devices in tandem without employing an external grid bias on any of the stages.

Another object of the invention is to provide a repeater employing a pluralityv of electron discharge devices in cascade wherein one of saidof a preceding tube and the grid 'of said preceding tube is connected to the cathode of the succeedingtube together with means for limiti'ngthe' normal plate current or the said succcedingtube.

A rther feature of the invention relates to an amplifier system employing a plurality of cascaded electron discharge devices wherein the grid of one device is connected directly to the cathode of a preceding device, together with mean'sfor maintaining said connected grid and cathode at substantially ground potential without substantially aifecting the amplifying powers of the system.

Another feature of the invention relates to an amplifying stage employing an electron discharge device, the input circuit of said device being provided with another electron discharge device which compensates for the grid loss of the first mentioned amplifier device, together withmeans for limiting the normal plate current of the said,

device to a minimum value.

Another feature relates to the novel organization and arrangement of elements and circuits which go to make up an efilcient amplifier system capable of operating without distortion, and

without employing so-called negative grid bias.

Other features and advantages not specifically enumerated will be apparent after a consideration of the following detail descriptions and the appended claims.

Referring to the drawings:

Fig. 1 represents an amplifier circuit to which the invention is especially well adapted. This circuit is of the type disclosed and claimed in application Serial No. 394,172, filed September 21, 1929, patented May 22, 1934, No. 1,959,540;

Fig. 2 shows the circuit of Fig. 1 modified in accordance with the invention to maintain the normal plate current of the second tube at a low value;

Fig. 3 shows substantially the same circuit as Fig. 2, and in addition shows in detail the method of energizing the filament cathode from a direct current source;

Fig. 4 shows the system of Fig. 2 with means for energizing the cathodes from an alternating current source; 7

Fig. 5 is a typical schematic circuit diagram showing the invention applied to a sound reproducing system.

Referring more particularly to Fig. 1, the numerals l and 2 represent schematically audions, orelectron discharge devices 01' the type employing an electron emitting cathode, a control grid and a plate or anode. The cathode 3 of the device I is directly connected by a conductor I to the control grid 5 of the device 2, and similarly the cathode 6 of the device 2 is connected by a conductor I through an input device or coil 8 to the control grid 9 of the device I. The operating potential for the anode Iii and the anode II is derived in accordance with usual practice, from a direct current source i2, the positive end of which is connected to the said anodes and the negative end of which is grounded. In 'ad- ,dition, there is a connection i3 between the negative end of the source I! and the cathode 6 in accordance with standard practice. In other words, the output circuit of the device 2 comprises the anode il, theprimary winding ll of an output transformer source I2 and cathode 6. The input circuit for said device 2 comprises grid 5, conductor 4, cathode 3, the electron stream between members 3 and Ill, conductor I5, source i2, cathode G. In other words the input circuit for the device 2 includes the electron stream between the cathode 3 and the anode ID. This electron stream is adapted to be varied in accordance with well known principles by the control grid 9, which has its potential varied Y by the input element 9;as described in said application, Serial No. 394,172. The variations in potential of the grid 9.are repeated as corresponding charges on the grid 5. One explana-' tion. for this-, 'repeating action may be that as the grid 9 varies, the number of electrons leaving the fllament'fo r the plate It, correspondingly Q vary, and therefore the charge or potential condition of the cathode I will follow the potential changes in the grid 9. Similarly the. potentials of-grid 5 corresponding to the potentials of grid 9 vary the electron stream between members 6 ,and II, and thus-control the current in the output circuit o f-the device}.

As described in said application, the grid 5 requires no external negative bias to enable the said device 2 to amplify the impressed potentials witlr'inaximum faithfulness. In other words.

even though the grid 5 should swing positively there would be no disproportion in the plate current as compared with the plate current produced when the said grid 5 should swing an equal amount negatively. As a matter of fact,

with the particular circuit arrangement shown in Fig. l, the grid 5 is at alltimes essentially positive with respect to the associated cathode 6, regardless of the potential vvariations on the grid 9. i

Under these conditions therefore, there is a relatively" high normal plate current flowing through the output circuit of the device 2.

In otherwords, the main average potential of the grid 5 with respect to the cathode 6 is relatively high and positive. The average normal plate -'current corresponding to this average positive ing and materially reducing the normal plate current of the device 2 without materially affecting the amplifying powers of the system. In Fig. 2 the corresponding elements to those of Fig. 1 are designated by the same numerals. From an inspection of Fig. 2 it will be noticed that the only difference is that the connection 4' between the cathode 3 and the grid 5 is connected to ground through a reactance coil It. If the call I 6 is of an extremely low ohmic resistance, then the grid 5 may be considered to be practically at ground potential when no alternating E. M. F.s are impressed on the grid 9.

In other words, the normal current from source l2 divides, one portion passing from the positive pole of source l2, conductor l5, anode HI, cathode 3, high reactance l6, to the negative pole of the source l2. At the point I! the current divides and part flows to the grid 5, cathode 6, and returning to the negative end of the source l2. However, since the ohmic resistance of the reactance I6 is vanishingly small, the potential drop. thereacross will be substantially negligible and the grid 5 will remain at substantially ground potential.

When an alternating E. M. F. is impressed 1 acteristic required for the system as a whole.

upon the grid 9 there is produced a corresponding change in the electron stream between elements 3 'and Ill. Preferably the inductance of coil I 6 is so large'that for the lowest impressed amazes frequency its reactive impedance is greater than the plate-cathode impedanee'of the device I. Under these conditions, therefore the reactive voltage developed by the passage of the signal -variations through the coil Hi will be applied directly between the grid 5 and the cathode 5. and will produce corresponding changes in the output circuit of the device 2.

Although Fig.2 of the drawings shows the grid 5 at substantially ground potential under normal conditions, it will-be understood that'the normal potential of the grid 5 may be at any value determined by the desired normalcurrent' 'in the output'circuit of device 2.-- Thus a suitable source of steady potential may be inserted between the coil l9 and the ground, although satisfactory operation is secured without such external potential, and the circuit of Fig. 2 may be arranged to provide any frequency-gain char- For example, the' coil 15 may be provided with any other form of reacta'nce or resistance in shunt and/or in series. therewith in order to obtain different voltage drops for the various frequencies, or if desired, these additional reactances may be used for the purpose of controlling the phase angles between the various impressed frequencies.

For example, a resistance connected in parallel "with the coil It provides a simple and eil'lclent method of obtaining uniform gain at all audio frequencies. It will be understood, of course, that the circuit of Fig. 2 may be used for the transmission of any range of frequencies,

for example, if the system is designed to transmit audio frequencies then the coil I 6 will be designed to have an extremely low ohmic resistance, but a high reactance to the audio frequencies. Similarly, if the system is to be used for the transmission of radio frequencies, the coil It will likewise havevery low resistance, but will have high reactance to the radio frequencies.

While the circuit of Fig. 1 shows the output load represented schematically by a load resistance, it will be understood that this is-purely illustrative and that instead of a resistance load,

any other type of load my be employed and this load circuit may be coupled to the tube 2 in any other manner than by transformer coupling as shown.

While Fig. 2 does not show the particular circuits for rendering the cathodes 3 and 6 emissive, it will be understood that any suitable filament heating circuit ,may be employed.

For example, Fig. 3 shows a circuit arrangement whereby the same current used for the anode supply may be used for heating the iila-- ments. The current supply conductors it are adapted to be connected to a suitable source of direct current and resistances I9 and 20 may be connected in series with the cathodes 3 and 6 .to provide the proper value of current for heating these filaments. In addition it may be found desirable to employ a pair of high reactance coils 2| and 22 in circuit with both legs of the filament 3, in place of a single reactance such as schematically shown in Fig. 2. The reactance coils 2| and 22 may be on separate cores, or if desired, they may be wound on' a single core provided that the twoiwindiugs 2| and 22 are connected in such a direction that they will aid each other for alternating currents, and oppose each other for direct currents, and preferably, al-

though not necessarily, the same number of turns may be employed on each coil.

With the circuit arrangement of Fig. 3 it is preferred to employ, for the tube I, an audion which requires low filament current, and has a low amplification factor. For example, one type of tube that has been found successful for this purpose employs a filament current of 0.06 amp.

and has an amplification factor of 3.5.

a/case the heater filament 23 and the electron filament are connected in parallel with the secondary winding 25 of a filament supply transformer whose primary winding 26 is connected to a suitable .source of alternating current. The direct connection between the cathode 24 and the grid 5 is maintained at substantially ground potential, it being connected to ground thru the high reactance, low resistance coil I6 as above described. The grid return for the tube 2 is preferably, although not necessarily, effected to the midpoint of the transformer winding 25 in accordance with usual practice. The operation of the circuit of Fig. 4 is substantially the same as that described in connection with Fig. 2. and further description thereof is not believed necessary at this point.

Fig. 5 shows a typical circuit arrangement embodying the invention in a sound reproducin system. In this figure the numeral 21 represents a sound record of any well known type, which by means of the pick-up device 28, is translated into corresponding potential variations. These potential variations are impressed upon the grid cathode circuit of the audion 29, the output circuit of which is coupled, by means of the transformer 30, to the input circuit of the tube 3| which corresponds to-the tube I of Figs. 1 to 4 inclusive. The amplified variations impressed upon the grid 32 of device 3| are repeated to the grid 33 of the audion device 34 in the manner set forth in application Serial No. 394,172. The grid is likewise connected through the high reactance coil 35 to the conductor 36, which may be at ground or other selected fixed potential for the purpose of limiting or controlling the normal plate current in the device 3|. as hereinabove described. The grid 33 therefore responds to the potential drops 'across the reactance 35, and correspondingly varies the output of the tube 34, which is coupled by a suitable output circuit to the sound reproducing device 31. While the source of potential for the anodes and cathodes of the respective tubes is not shown in Fig. 5, the manner of connecting these sources to the respective electrodes is in accordance. with standard practice, and no description thereof is believed necessary.

While Figs. 1 to' 5 show the invention embodied in two separate audions having their grids and cathodes directly interconnected, it will be understood that the invention rnay also be practiced by combining the said audions in a single audion of the type disclosed in Patent No. 2,002,207, May 21, 1935.

.While the invention has been disclosed in connection with specific types of electron discharge devices, and associated apparatus, it will be understood that the invention is not limited thereto, but may be practiced with other well known forms of apparatus without departing from the spirit and scope of the invention. One of the important advantages of applicants specific circuit arrangements is that-the variation in potential of the first grid with respect to its cathode is in phase with the variations in potential of the second grid with respect to its cathode. In other words, as an incoming signal raises the potential of the grid 1 with respect to its cathode 3, there is a corresponding increase in potential applied across the grid 5 and the cathode 6, so that as the grid 9 swings positively with respect to its cathode 3, likewise the grid 5 swings positively with respect to its cathode 5. In this sense, therefore, the variations of grid potentials with respect to the associated cathodes are in phase.

What is claimed is:

1. In a wave transmission system a first electron discharge device, a second electron discharge device, a high-reactance coil connected in shunt to the grid-cathode of the first device and the grid-cathode of the second device, one terminal of said reactance coil being connected to ground for maintaining the grid of the second device at or near ground potential when no signals are being transmitted.

2. In a wave repeating system a series of electron discharge devices with the grid of one device directly connect-ed to the cathode of a preceding device, and reactance means for maintaining the grid of said second device at substantially ground potential when no signals are being repeated.

3. In a transmission system the combination of a first electron discharge device, a second electron discharge device, each device having a gridcathode input circuit, means common to both said input circuits and connecmd in series with the grid-cathode of the first device to limit the normal plate current of the second device, and circuit arrangements for allowing said second device to operate with a positive static bias on the grid without causing distortion in the output.

4. In an amplifying system the combination of a first electron discharge device, a second electron discharge device, a high reactance connected in common to the grid-cathode circuits of each of said devices, and circuit arrangements for impressing signal variations on the grid of the first device so that variations in potential between the grid of the first device and the cathode of the second device are in phase with the variations in potential between the grid and cathode of the second device.

5. A combination according to claim 4 in which the high reactance has low ohmic resistance.

6. In an amplifying system the combination'ol a first electron discharge. device, a second electron discharge device, the cathode of said first device.

being directly connected to the grid of said second device, andthe cathode of said second device being connected in a direct current circuit to the grid of said first device, means for limiting the normal anode currents of said second device, and circuit arrangements for impressing signal variations on the grid of the first device so that variations in potential between the grid of the first device and the cathode of the seconddevice are in phase with the variations in potential between the grid and cathode of the second device.

'7. The combination according to claim 6 in which the meansfor limiting the anode current of the second device includes a high reactance between the grid of said second device and the cathode thereof.

8. In an amplifier system a first electron discharge device, a second electron discharge device,

a source of anode potential for said second device, a connection between the grid of said second device and the positive terminal of said source, said connection including the cathode-anode space of the first. device, means for limiting the normal anode current of the second device when no signals are being transmitted. and circuit arrangements for impressing signal variations on the grid of the first device so that variations in potential between said grid and the cathode of the second device are in phase with the variations in potential between the grid and cathode of. the second device.

9. A system according to claim 8 in which the -means for limiting the normal anode current in-- cludes a low resistance high reactance element connected between the grid of said second device and ground, said ground being at a negative pole of the anode supply.

10. In an amplifier system the combination of I a first electron discharge device, a second electron discharge device, each of said devices having a cathode, a control grid and an anode, a low resistance high reactance element, the cathode of the first device being connected to one terminal of said reactance and the grid of the first device and the cathode of the second device being connected to the other terminal of said reactance.

13. A wave repeating system comprising a pair of electric discharge devices each having cathode, anode and control electrodes, a low-resistance high-reactance connected in shunt to the cathode and control electrode of the second device, and a signal input circuit connected in series with said reactance across the cathode and control electrode oi. the first device.

14. A wave repeating system according to claim 13 in which one end of said reactance is substantially at ground potential with respect to the signal variations.

15. A wave repeating system according to charge devices with the load of the first device between the cathode and the negative terminal of the anode supply, a conductive path for maintaining the grid of the second device at a predetermined static potential with respect to ground to limit the normal anode current of said second device while allowing said second device to operate with positive grid swing without causing distortion. I

- 18. A wave repeating system comprising a pair of electric discharge devices each having cathode,

anode and control electrodes, 8. signal input coil having one end connected only to the grid of the first device, the other end of said coil being directly connected to the cathode of the second; device, and a high reactance direct current path connecting both said cathodes.

19. A wave repeating system comprising a pair of electric discharge devices eachhaving anode, cathode and control electrodes, a direct current connection from the cathode of the first device to the grid of. the second device, and a highreactance impedance of relatively low ohmic resistance for maintaining the grid of the second device in the neighborhood of ground potential when no signals are being repeated.

20. A wave repeating system comprising 'a pair of electric discharge devices each having'cathode, anode and control electrodes, a source of anode potential having its positive pole connected to the anode of the first device and its negative terminal connected to the cathode of the second device, a direct current connection from the cathode of the first device to the grid of the second device, and a high-reactance shunting the grid-cathode of the second device.

21. A wave repeating system comprising a pair of electric discharge devices each having cathode, anode and control electrodes,means for impressing signal variations. to be repeated across the grid of the first device and the cathode of the second device, a metallic connection betweenthe cathode of the first device and the grid of the second device to maintain the same phase rela tion between the signal variations impressed on both said grids, and an inductive reactance of low ohmic resistance connecting the cathode of the first device and thegrid of the second device to the negative terminal of the anode supply.

22. In a transmission system of the type employing two sets of electron discharge elements each set comprising a cathode, anode and control electrode, a direct connection between the cathode oi the first set and the control electrode of the second, means for limiting the normal anode current of. the second set when no signals are being transmitted, said means consisting of means for impressing signal variations on the' control electrode of the first set, said input means making a direct current path between the last mentioned control electrode and a negative pole of the said anode potential supply.

23. A combination according to claim 22 in which said means for limiting the normal anode current comprises a resistance.

24. A combination according to claim 22 in which said means for limiting the normal anode current comprises a reactance.

25. A combination according to. claim 22 in which the said negative pole of the anode supply is substantially at ground potential with respect to the signals to be transmitted.

26. A combination according to claim .22 in which the said cathode of the second set of elements is substantially at ground potential with cathode of the first set and the control electrode of the second, means for limiting the normal anode current of the second set when no signals are being transmitted, said means consisting of a direct current path between the grid and cathode of the second set, an input circuit arrangement for impressing signal variations between the control electrode of the first set and the cathode of the control electrode of said second valve; means including circuit connections for connecting the anode circuits of said valves in parallel across said source; and a choke coil inserted in the cathode lead oifsaid first valve.

29. In an electrical system, a first thermionic valve; a second thermionic valve, said valves having cathode grid and anode electrodes; a

source of anode potential; a direct conductive coupling connection from the cathode of said first valve to the grid of said second valve; means including circuit connections for connecting the anode circuits of said valves in parallel across said source; and a resistance and a choke coil in series inserted in the cathode lead of said first valve.

30. In an electric system, a first thermionic valve; a second thermionic valve, said valves having cathode grid and anode electrodes; a source of anode potential supply; a direct conductive coupling connection from the cathode of said first valve to the grid of said second valve; means including circuit connections for connecting the anode of circuits of. said valves in parallel across said source; impedance means inserted in the cathode leads of said valves comprising a choke coil in the cathode lead of said first valve for maintaining predetermined operating potentials of said electrodes and for producing coupling potential for said second valve.

31. In a system as described in claim 30, at least one further direct current circuit extending from the positive pole 01 said source over the cathode of said second valve, to'the negative pole of said source.

JULIUS GOURGUES ACEVES.

, Disclaimer sron SYSTEM. Patent -ELEG'I'RICAL TRANSMIS- Disclaimer filed Nov. 2,

1950, by the assignee, Remoo Electronic, Inc.

Hereb enters this disclaimer to claims 6, 22, 23, and 27 of said patent.

[ flioial Gazette December 5, 1950.]

cathode of the first set and the control electrode of the second, means for limiting the normal anode current of the second set when no signals are being transmitted, said means consisting of a direct current path between the grid and cathode of the second set, an input circuit arrangement for impressing signal variations between the control electrode of the first set and the cathode of the control electrode of said second valve; means including circuit connections for connecting the anode circuits of said valves in parallel across said source; and a choke coil inserted in the cathode lead oifsaid first valve.

29. In an electrical system, a first thermionic valve; a second thermionic valve, said valves having cathode grid and anode electrodes; a

source of anode potential; a direct conductive coupling connection from the cathode of said first valve to the grid of said second valve; means including circuit connections for connecting the anode circuits of said valves in parallel across said source; and a resistance and a choke coil in series inserted in the cathode lead of said first valve.

30. In an electric system, a first thermionic valve; a second thermionic valve, said valves having cathode grid and anode electrodes; a source of anode potential supply; a direct conductive coupling connection from the cathode of said first valve to the grid of said second valve; means including circuit connections for connecting the anode of circuits of. said valves in parallel across said source; impedance means inserted in the cathode leads of said valves comprising a choke coil in the cathode lead of said first valve for maintaining predetermined operating potentials of said electrodes and for producing coupling potential for said second valve.

31. In a system as described in claim 30, at least one further direct current circuit extending from the positive pole 01 said source over the cathode of said second valve, to'the negative pole of said source.

JULIUS GOURGUES ACEVES.

, Disclaimer sron SYSTEM. Patent -ELEG'I'RICAL TRANSMIS- Disclaimer filed Nov. 2,

1950, by the assignee, Remoo Electronic, Inc.

Hereb enters this disclaimer to claims 6, 22, 23, and 27 of said patent.

[ flioial Gazette December 5, 1950.]

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