US1882850A - Frequency producer - Google Patents

Description

. i8, 1932. w, A, MARRISON ,882,85

FREQUENCY PRODUCER Filed Aug. 5, 1929 2 sheets-sheet l /f /sy HGB-A w; Mi? M' BMyTM/wo A TTOHNEY c. E, i932.

W. A. MARRISON FREQUENCY PRODUCER Filed Aug. 5, 1929 2 Sheets-Sheet 2 /NVEN TOR W A. MARR/SON Big/wy A TTORNEV Patented Oct. 18, 1932 WARREN A. HARRISON, OF IMAIELIEWOOI), NEW JERSEY, ASSIGNOR TO BELL TELEPHONE LABORATORIES, INCORPORATED, OF NEW YORK, N. Y?, A CORPORATION OF NEW YORK Application mea August 5, 1929. serial No. 383,622.

This invention relates to harmonic frequency production, and especially to the production of electrical variations the frequency of which has a predetermined integral relation to the frequency of given electrical variations 'from which the harmonic frequency variations are derived. Objects of the vinvention are: to generate waves whose freqeuncy has a given integral relat: on to a given wave 1n a more simple and positlve manner, and with greater stability,

than as in accordance with prior inventions,

-with greater economy of operation and of quency a predetermined-fixed path or figure.v

The desired harmonic frequency is a function of the frequency of incidence of such wave on a target interposed in its path. If, for example, the target has theY form of a spoked wheel the frequency of incidence of the ray on such a target,A and therefore the frequency of variation of the electrical charge on the target from the ilnpinging electrons, is a function of the number of spokes. The variation in charge is translatedvinto a correspondingly varying current by,'for eX- ample, ,a thermionic repeating device the control element of which is connected to the taret. g rl`he invention will be more readily understood from the following detailed description taken in connection with the accompanying drawings, in which:

Fig. 1 represents one embodiment .employing a cathode ray tube equipped with deflector plates and a single target connected to a space discharge amplifier;

Fig. 2 represents another embodiment employing a cathode ray tube equipped with two parallel targets associated with apush-pull amplifier having differentially-connected output circuits;

Fig. 3 'represents still another embodiment employing' a cathode ray tube equipped with a plurality of parallel targets associated with thermionic amplifying devices having cumulatively connected output circuits;

Fig. 3A is a developed view of the three targets employed in the device 'of Fig. 3; Fig. 4 is a set of curves showing various harmonic fre uencies that may be produced from the fun amental wave supplied to the deflector plates in systemssimilar to those shown in Figs. 1 to 3.

Referring to Fig. 1, the reference numeral 1 designates a cathode ray tube similar to that shown in U. S. Patent 1,603,284, grantedv to J. B. Johnson October 19, 1926, except that the fluorescent screen is omitted. The .tube is equipped with a cathode 2, a screening electrode 3, an anode 4, two pairs of deflecting plates 5 and 6, and a target 7 w'hich has a, plurality of projections or spokes. The target has an odd or even number of spokes depending on whether odd or even harmonics of the frequency supplied to the deflector plates are desired. It should be observed that the wi dth of each spoke varies directly as the distance from the center and that at any given radius, the distance between adjacent spokes equals the width of the spokes.

Heating current for cathode 2 is su plied from battery 8 and positive potential or the anode 4 is supplied from battery 9. The transformer 10,.. including primary Winding 11 and secondary winding 12, serves asa means of transferring energy of the fundamental frequency to the cathode ray tube deector plates. Condenser 13 and resistance 14 together with the secondary winding 12 of transformer 10 form a phase-splitter similar to that described in my copending application No. 252,628, tiled February 7, 1928,A Patent No. 1,768,262, granted June 24, 1930.4

The reference numeral 15 designates a space discharge tube having the usual cathode, anode and control electrode, the last mentioned element being connectedto ltarget 7. The cathode is -heated bylenergy supplied from battery 16. Energy for the anode ciry cuit is suppliedfromI battery 17, whichhas itspo'sitive terminal connected tothe anode through ,they rimary winding 18 of transformer '19. transformer' 19 may be connected to another amplifier or4 to a work circuit. The high resistance grid leak 21 permits the electrons to flow from the control electrode to the cathode at such a rate as will prevent the control electrode froni becoming excessively negative and blocking the tube. y

In operation, electrons emanate from the heated cathode 2 and are drawn 'through the orifice in the screening electrode 3 to the tubular anode 4. The velocity of the electrons is such that some of them'y pass through the tubular anode and impinge upon target 7 At the same time energy of a fundamental frequency is supplied through transformer to the two V'pairs of defiector plates 5 and 6. The potential applied to the plates 5 1s 90 outof phase with respect to that impressed on the plates 6 since the for-mer is equal to the drop across a condenser, whereas the latter is equal to the drop across a resistance. The alternating E. M. F. across plates 5 tends to produce vertical oscillations of the beam and, at the same time, the E. M. F. across plates 6 tends to produce horizontal oscillations. The beam is therefore caused to describe a hollow conically shaped figure the projection of which on the spokes of target 7 is a circle. This may be shown mathematically, 'as follows:

Let

w=a sin pt=voltage component applied to plates 6 but sinp pt-l-cos2 pt=1.

Therefore 42+y2=a2=a circle.

Electrons impinging upon the spokes of thetarget in succession during one revolution of the beam, that is, during one complete cycle of the input E. M. F. impressed upon the deflector plates, render the target, and therefore the control electrode of space`discharge tube 15, negative periodically dependhe secondarywinding 20 ofI assassin ing on the number of spokes on the target. As in taccordance with a well known principle eachof these negative .chargeson the control electrode of tube tends to decrease the current in the anode circuit with the result that therelis induced in the secondary winding ari alternating current lWhose freuency is equal to the product of the ori inal requency impressed upon the defiector p ates and the total number of spokes on the target 7.

Either odd or even harmonics of the fundamental Wave are produced depending on the number of spokes. The Wave produced willl` b e substantially a sine wave inasmuch as thel control electrode is energized during la, period equal to that in which it is not'energized, in view of the fact, as pointed lout above, that the arc traversed by the beam on each spoke is equal to the arc traversed between adjacent spokes. y

The sequence of the steps in the production of the harmonic current induced in the sec` when the target ,has nine projections. In

both cases vthe numerals refer to the individual spokes on the target. The order of the harmonic produced by this arrangement. it will be observed is determined solely by the number of rojections on the target'.

Desired variations in the harmonic frequency may be easil and quickly achieved by replacing the tu e in use with a tube whose target possesses the desired number of spokes. The necessity of changing the tubes in order to obtain a dii'erent harmonic may be eliminated, however, by designing a single target .to/have a different number of spokes atdiflerent radii and properly varyingthe radius'of` the beam traced. For example, a single concentric targetmaybe constructed to have three spokes ata .5 cm. ra; dius, live at 1 cm. and'sevenat 1.5 cms. in

which case the third, iifthfor-sseventh harmonic may be produced by suitably varying either the deflector plate or 'anqdevoltage to produce theproper.size'circle.\ c f Fig. 2 shows an arrangement similar to Ithat of Fig. I1l except that in Fig. 2 two targets and a push-pull amplifier are'utilized.

The reference'numerals 1 to 6' and 8 to 14' in Fig. 2 denote elements Whose functionsI are similar -to theI elementshaving corresponding' designations m' Fig. 1. The refonly by the minimum practicable spacing in orderthat the beam will trace substantially the same size circle on all targets. .W'ith the targets close together any variation in the amplitude of the impressed wave will change the size of the trace on all targets an equal amount with the result that undesired amplitude variations will not cause frequency distortion in the output. The targets may be spaced relatively far apart, however, provided that they are symmetrical in design. lt isimmaterial as to what their actual diameters are so long as the spokes of each target intercept the beam. @i course, with an appreciable spacing between the targets considerations of economy of material require the diameters to increase with the distance from the source of the beam.

The push-pull amplifier comprises space discharge tubes 2e and 25 each of which has the usual cathode, anode and control electrode. Thecontrol electrodes of these tubes are directly connected to targets 22 and 23, respectively. Associated with space discharge tube 2e is an input circuit which includes a grid leal?. resistance 2G and an output circuit which includes the primary winding 28 of output transformer o0. Similarly, the input circuit of tube 25 includes resistance 2T and the output circuit includes Winding 29 oftransformer 30. The secondary winding 3l may be connected to anotherampliier or to a work circuit. lncluded also in the output circuit of each tube is battery 17 which has its positive terminal connected to the anodes of both tubes. Energy for heating the cathode of both tubes is supplied from battery 16.

The cathode ray tube produces an electronic stream whichis deflected so as to produce ahollow conical envelope in the manner described in connection with Fig. l, .and in tracinga circular path on the targets the beam impinges alternately on the spokes of targets 22 and 23 and thus alternately energizes the control electrode of each of tubes 24. and 25 at a frequency proportionlto the number of spokes on each target.

The ampiiiier operation is similar to that of the ordinary push-pull amplifier. "Vhen the control electrode of one tube is rendered negative by the charge on the associated target, the control electrode of the other'tube is relatively positive. The fundamental frequency pioduced in the anode circuits of each of tubes 2e and 25 is therefore that multiple of the frequency of the potential originally supplied to the deiiector plates measured by the product of the original frequency and the number of spokes on the respective target.

This fundamental frequency therefore is ank odd or even harmonic frequency of the fundamental wave on the delector plates depending on whether each tar et contains an odd or an even number of spo es. However, as explained below, this fundamental is not transmitted to the work circuit.

Inasmuch asthe primary windings 28 and 29 are differentially related to the secondary winding 8l when takin the relative phases of the currents flowing therethrough the fundamental and odd harmonic frequencies present in each of the tube anode circuits are balanc'ed' out and only even harmonics of the wave originally supplied to transformerv 10 are eventually transmitted to the work circuit through transformer 30. Consequently, in this system the order of harmonic produced is always even no matter whether the targets have an oddyor even number of spokes. Referring again to Fig. 4, the harmonic frequencies produced b an arrangement similar to that shown in ig. 2 are'illustrated in curves D, D', E andE, A. being the fundamental wave. Curve D represents the combined anode currents of both tubes, resulting from the use of' two targets, each having four spokes. rlhe numerals above the line refer to the spokes on one target and those below this line refer to the spokes on the other target. Anode currents of the frequency represented by .curve D, which also repren sents the fourth harmonic of the fundamental wave A, are balanced out because of the dif ferential relationship between the primary windings of transformer 30; and the lowest frequency transferred to the secondary winding 3l is the second harmonic of the anode frequency, that is, the eighth harmonic of the fundamental wave which is represented by curve D". ln a similar manner curve E illustrates the frequency of the combined anode currents of both tubes obtained by using two targets each equipped with three spokes; and curve E shows the ultimate frequenc transmitted to the work circuit which in t is case isr the sixth harmonic of the funda-mental wave. Thus, in the arrangement shown in Fig. 2 only even harmonics of the fundamental wave are available for use in the work circuit.

Fig. 3 represents a modification of the invention for producing a greater frequency multiplication and incidentally, either odd or even harmonics of the fundamental wave; As in Fig. 2 the reference numerals 1 to 6 and 8 to 14 designate'el'emcnts which perform the same functions as those similarly designated in Fig. l. Three parallel targets 'designated 32, 33 and 34 and similar in construction, are interposed in the path of the electronic beam which is caused to revolve in the manner described above.

rl`he targets I are-shownl spaced from each other but inthe preferable arrangement they should be relatively close together as discussed in connection with the device of Fig. 2. As shown in the developed view in Fig. 3A the spokes of targets 33 and 34 'are positioned in respect to target 32and to each other so that the revolving beam will impinge on the three targets in succession.

Space discharge tubes 35, 36 and 37 each includes an anode, cathode and a control electrodeg, the control electrodes of these tubes are connected respectively to targets 34, 33 and 32. The high resistances 41, 42

i and 43 connected in the input circuits of three separate transformer primary windings each connected to a s eparate anode may be substituted in lace of the arrangement shown without agcting the result. Transformer 39, including windings 38 and 40, serves to transfer energy from the space discharge tube output circuits to the work circuit.

The beam is caused to revolve in thel manner explained in connection with Figs. land 2 and consequently the control electrodes of tubes 35, 36 and 37 become negatively charged in succession because of the staggered rela.- tionship of the targets. Each separate charge, however, causes a'corresponding decrease in the current flowing through winding 38 Aso that the current through Ithis Winding possesses a fundamental frequency equal to the product of the fundamental Wave sup'- plied to transformer 1,0 and the total number of spokes on all targets, Inasmuch l'as the total number of spokes ,may be an odd or even number'either odd or even harmonics of the fundamental wave may be obtained as the fundamental. frequency in winding 38.

This fundamental frequency is induced inwinding 40 for utilization in the work circuit together With its harmonicsin all cases except in the single instance whnltwo targets only are used, in whichv caselthe even harmonics willbebalanced out. f

Curves F and F of Fig. 4 show the frequency of the, anode current and the frequency of the current in winding40, respectively, when three targets of four' spokes each are emplo ed. `The numerals indicate the order in wh1ch the individual spokes on the three targets become energized. y' It' 'will thus be seen that the frequency represented by. curve F is the twelfth harmonic of the fundamental wave A, twelve being the total number of spokes on the three targets. Curves G and G illustrate the corresponding frequencies obtained when three targets of three spokes each are employed. In this case the fundamental frequency .in Winding 40 represented by curve G is the ninth harmonicl of the fundamental wave A. Either` odd or even harmonics are therefore obtained by this arrangement, the odd harmonics being a multiple of the number of targets.

In the various embodiments of the invention described in connection with Figs. 1 to 3 and the associated curves of Fig. 4 the cathode ray tube is shown equipped with delector plates for generating a beam and caus- -ing it to revolve conically. The invention,

however, is not limited to this specific means for deflecting the beam, but rather includes broadly any means for detlecting an electronic beam such as, for example, electromagnetic coils located adjacent .to the stream', one pair of coils being at right angles to another pair and energized y a current in quadrature.

It should also be understood that the applicaton of the invention is not intended to be confined to the type of cathode ray tube shown in these specific embodiments but includes broadly any electron-emitting tube of the evacuated or gas-filled type.

What is claimed is:

1I The method'of producingharmonic fre-` quencies having a sine wave form substantially utilizing an electron beam and a conductive element containing several projections which comprises causing the beam to impinge onand flow by the projections-alternately for equal time intervals during each cycle ofthe fundamental wave and utilizing the ielectrons absorbed by said element to vary the current in an external circuit.

2. The method of producing harmonic freuencies having a sine Wave form substantially utilizing Ia cathode ray, a conductive element' containing a plurality of projecltionsand an amplifier, which comprises mov- `ing the ray at a speed determined by theA frequency of the fundamental wave, causing it 'Ito traverse land avoidthe projections alternately during'equal time intervals cyclically, and transferring'the electrons on said projections to the control electrode of said amliter. f p 3. The vmethod -of'producing harmonic frequencies having a 4sine wave form substantially utilizing a cathode ray, an absorbing means, means for de ecting the cathode ray,

and anrenergized space discharge tube, which comprises deflecting theray c clically in ac cordance with the fundamenta wave,'absorb ing and not absorbing energy therefrom alternately during equal time intervals at a aoc.

frequency vcorresponding to the desired harmonic, and transferring the vabsorbed energy to lthe control electrode of the space discharge Ul e.

4. The method of producing harmonic frequencies having a sine wave form substantially of a fundamental wave utilizing a cathode ray, a plurality of conductive elements each containing a plurality of projections, and a plurality of space discharge tubes, which comprises causing the ray to impinge on all projections of the elements alternately for successive equal time intervals during one cycle of the fundamental wave, transferring the energyabsorbed by each element to the control element of a different discharge tube, and combining the outputv current of said tubes. Y

5. In combination with means for producing a cathode ray'and means for varying the direction of said ray cyclically, additional means comprising conductive elements connected to each other through a path of substantially zero impedance and arranged to intercept and avoid vsaid ray alternately during equal time intervals', and means controlled by said elements for regulating the iow of energy in a separate circuit.

6. In combination, a device for producing a stream of electrons, means for varying the direction of said stream cyclically, a target included in said device and having a plurality of projections, said projections being positioned to receive and avoid said electrons al ternately and in succession during equal time intervals, and means connected to said target for varying the current in an external circuit.

7 In combination, means including a cathode and an anode for obtaining an electron stream, potential means including defiector plates adjacent to said stream for cyclically delecting the stream, means comprising a conductive target having a plurality of projections located in the path of said stream, the width and spacing of the projections in said path being equal, said target connected to the control electrode of a space discharge amplier having an output circuit. Y

8. In combination,y a cathode ray tube, means associated therewith for causing the ray produced to revolve conically at a predetermined rate, a target included in said tube and having a plurality of radial projections in the path of the ray, the width and spacing of the projections in said path being equal, `1a space dischargetube having its control electrode connected to said target, and an output circuit associated therewith. j

` 9. In combination, means for producing an electron beam, means for cyclically deflecting said beam in accordance with the frequency of gered in respect to .each other, and potential responsive means associated with a common work circuit connected to each of the targets.

10. In combination with means for producing an electronic stream, means for causing the stream to revolve conically at aredeter- -mined rate, means for continually a sorbing energy from said stream comprising a plurality of parallel targets each containing a plurality of radial projections arranged to be successively energized, and separate means connected to each target for varying the flow of energy in an external circuit.

11. In combination, a Braun tube adapted to produce a ray revolving in synchronism with a fundamental wave, means for causing the wave to impinge in succession on a plurality of targets, a plurality of thermionic devices having diiierentially connected input circuits and output circuits associated with a common work circuit, each of the said devices being controlled by one of the targets.

12. In a frequency multiplication system, a cathode ray tube, means for producing a cathode ray therein, a source of variable potential, means for obtaining quadrature potentials therefrom, means for revolving the ray conically comprising a plurality of deflector plates adjacent to the ray and energized by the quadrature potential, a plurality of electrodes arranged to successively absorb energy from the ray, a plurality of thermionic devices each of which is controlled by one of the electrodes, the anode circuits of the said devices being associated with a common workl circuit.

In witness whereof, I hereunto subscribe my name this 2 day of August, 1929.

WARREN A. MARRISON.

a fundamental wave, means comprising parallel targets each having a plurality of protuberances in the ath of the beam, the protuberances of ad] acent targets bemg stag-

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