US2696522A - Visual reproduction of distant objects - Google Patents

Description

Dec. 7,1954 RlNEs 2,696,522

vxsum. REPRODUCTION OF DIs'rAm' OBJECTS Filed Jan. 22, 1944 2 Sheet-Sheet 1 Dec. 7, 1954 2 Sheets-Sheet 2 Filed Jan. 22, 1944 United States 2,696,522 Patented Dec. 7, 1954 VISUAL REPRODUCTION OF DISTANT OBJECTS Robert H. Rines, Brookline, Mass.

Application January 22, 1944, Serial No. 519,376

10 Claims. (Cl. 178--6.8)

The present invention relates to electric systems, and more particularly to radio-receiving systems that, while having more general fields of usefulness, are especially adapted for use in television.

An object of the invention is to provide a new and improved radio-receiving system.

Another object is to provide a new and improved television system.

Another object is to provide a novel combined radioand-television system.

Another object of the present invention is to provide a new and improved radio-locator system for both detecting the presence of a body and rendering it visible.

Other and further objects will be explained hereinafter and will be more particularly pointed out in the appended claims.

The invention will now be more fully explained in connection with the accompanying drawings, in which Fig. 1 is a diagrammatic view of circuits and apparatus arranged and constructed in accordance with a preferred embodiment thereof; Fig. 2 is a view of a modification; and Fig. 3 is a diagram showing an airplane object from which radio waves are reflected and scattered to the receiving system of Fig. 1.

An electromagnetic-wave generator 4 is shown exciting a dipole 2 to produce ultra-high-frequency pulsed-radio energy, say, of 3 or 1.5 centimeters microwave wavelength. A continuous-wave or any other type of modulated-wave generator may be employed, but pulsed energy, at present, has the advantage of economical and easy high-power ultra-high-frequency generation.

The waves emitted by the dipole 2 may be directed by a reflector 3 upon a parabolic reflector 6. The parabolic reflector 6 is shown directing the waves toward an ob- .ject, say, an airplane 8, from which they are reflected and scattered toward a receiving station.

At the receiving station, the radio waves thus reflected and scattered from the object 8 may be focused by an electromagnetic dielectric lens 5, such as polystyrene, upon a bank or array 7, comprising a plurality of normally ineffective insulated radio-receiving pick-up unit antenna elements. The dielectric lens may be replaced by any other type of well-known lens, mirror or other directive systems for focusing the electromagnetic energy scattered and reflected from the object 8 on the bank or array 7 of pick up elements.

The pick-up elements of the bank or array 7 are shown as metal strips or other conducting antenna sections, separated by insulation strips to prevent radio interference and interaction between the antenna sections, and arranged in the form of rows and columns, in the proximity of the focal plane of the lens 5. The first or uppermost row of the bank is illustrated as comprising the sections 10, 12, 14, 16, etc., shown as equally spaced horizontally. The second row from the top is shown comprising the sections 18, 20, 22. etc. The third or next-lower row is shown comprising the sections 24, 26, etc., and so on for the remaining rows of pick-up elements. Though only a small number of pick-up units is shown in each row, this is merely for illustrative purposes, in order not to confuse the disclosure. It will be understood that, in practice, a large number of pick-up units will be employed in each row, say, 180.

' The sections 10, 18, 24, etc., are arranged in the first or left-hand column. The sections 12, 20, 26, etc., are disposed in the second column from the left. The sec tions 14, 22, etc., are disposed in the third column from,

the left, and so on. There may be asmany columns as there are pick-up units in each row. Though each column is shown as comprising only a few pick-up units, this is again in order not to complicate the drawings. A system of rows and columns of antenna sections of dipole dimensions will produce good picture definition of large close-range objects for a three-centimeter wave, assuming an eight-inch-display cathode-ray-tube screen.

The pick-up units will. of course. all receive the reflected or scattered radio waves through the lens 5 simultaneously. There will be focused on each pick-up unit a radio-frequency voltage corresponding to the scattering from a corresponding area of the object 8. The pick-up elements will thus receive different field strengths of radio energy, corresponding to the amount of energy reflected or scattered from the various parts of the object 8 and converged upon the array 7 of pick-up elements by the lens 5. A radio-energy picture of the object 8, as will presently be explained, is thus recorded upon the array, specific elemental areas of which will correspond to specific elemental areas of the object 8. By means of the present invention, this radio-energy picture may be converted into a visible picture 123. According to the preferred embodiment of the invention, the visible picture 123 is caused to appear upon the fluorescent viewing screen 106 of a display cathode-ray oscilloscope tube 90. Though the tube 90, and also the hereinafterdescribed cathode-ray-oscilloscope-like member 89, areshown operating on the electrostatic principle, magnetic deflection or a combination of magnetic and electrostatic forces may be employed. The invention provides a means for producing upon the screen 106 images corresponding to the radio-frequency energy received by the pick-up elements.

Provision is made for first rendering the normally ineffective pick-up units 10. 12. 14. 16. etc., of the first row successively effective momentarily in the display circuits; for then rendering the pick- up units 18, 20, 22, etc., of the second row successively effective momentarily in the display circuit; for then rendering the pickup units 24, 26, etc., of the third row successively effective momentarily; and so on.

A preferred way of eifecting this result is with the aid of a novel electron-operated energy-scanning apparatus that, for the particular preferred radio-energy purposes described herein, comprises a plurality of insulated energy-storing devices shown as charging condensers and small rectifiers, equal in number to the number of pickup sections. The rectifiers may be uranium-oxide or silicon beads, and serve respectively, to rectify the energy received by the respective pick-up units. The charging condensers and the rectifiers are connected to the pick-up sections by conductors, which should be extremely short transmission lines, preferably no more than 3 or 4 wavelengths long. and all the conductors should be of substantially the same electrical length. The sections 10, 12, 14, 16, 18 and 24, for example, are shown connected by conductors 11, 15, 19, 23, 27 and 31, respectively, to rectifiers 13, 17, 21, 25, 29 and 33.

The conductor 11, for example, connects the section 10, through the rectifier 13, to a condenser plate 28; the conductor 15 connects the section 12, through the rectifier 17, to a condenser plate 30; the conductor 19 connects the section 14, through the rectifier 21, to a condenser plate 32; the conductor 23 connects the section 16, through the rectifier 25, to a condenser plate 34; the conductor 27 connects the section 18, through the rectifier 29, to a condenser plate 36; the conductor 31 connects the section 24, through the rectifier 33, to a condenser plate 42; and so on.

The condenser plates are shown arranged in an insulating-disc bank or array 9 of rows and columns to correspond to the bank or array 7 of rows and columns, respectively, of the pick-up sections. The first or uppermost row comprises the equally spaced condenser plates 28, 30, 32, 34, etc., corresponding to the pick- up antenna sections 10, 12, 14, 16, etc., of the first row of antenna sections. The second row from the top comprises the equally spaced condenser plates 36, 38, 40, etc., corresponding to the antenna sections 18, 20, 22, etc., of the second row of pick-up units. The third row comprises the equally spaced condenser plates 42, 44, etc., corresponding to the third row of sections 24, '26, etc., and so on. The first column of condenser plates 28, 36, 42, etc., corresponds similarly to the first column of sections 10, 18, 24, etc. Thesecon'd column of condenser plates 30, 38, 44, etc., corresponds to the secondcolumn of sections '12, 20, 26, etc. The thirdcolumn of condenser plates 32, 40, etc., corresponds to the third colurrm of sections 14, 22, etc., and so on.

The condenser plates -28, 30, 32, 34, etc., of the first row are shown respectively cooperating with condenser plates 35, 37, 39, 41, etc., that are all connected to a grounded condenser-strip 43. Condensers are thus provided, one plate of which is connected to the-strip 43, and the other plates =ofwhich are connected, through the respective rectifiers, to the sections 10, 1'2, '14, 16, etc.

The condenser plates 36, 38, 40, etc., 'of the second row are similarly shown respectively cooperating with condenser plates 45, 47, 49, etc., that are all connected to -another grounded-condenser strip'Sl. The condenser plates 42, 44, etc., of the-third row are similarly shown cooperating with-condenser plates53, '55, 'etc., that are 'all'connected to a third grounded conde'nser.-.strip 57, and

so on.

The condenserplates ofthe respective condensers are all preferably separated by the same distance. The condensers may conveniently have either large or small capacitance, varying, say, from micro-microfarads to farads, depending upon the type of antenna receiving circuits used.

The same result may, of course, be attained in other ways than through the use of the rectifiers. One such way is-to connect the antennae 10, 12, -14, -etc., directly -to the condenser plates 28, 30,32, 34, etc. The condensers must now, however, have a-small value of capacitance, in order to present a relatively high impedance to the radio-frequency energy. For 3-ce-ntimeter waves, capacitances of the order of l faradswvould be adequate. The short leads'11,-15,19, 23, 27, 31,'etc., should be connected by ultra-high frequency chokes, not shown, -to prevent interaction. These chokes will not permit the passage of current from one metal pick-up section to-the adjacently disposed metzilgpizk-up section during the hereinafterdescribed discharge or short-circuitin'g of the condensers, since the time of the discharge orshortcircuiting of each metal section is very short.

:The condenser plates-and strips-may be embedded in the insulating'disc 9, at the screen end of the cathoderay-oscilloscope-like -member 89, provided'with a vacuum-tube electron-gun part 58, comprising a cathode 95, a control-gridelectrode93 andan anode '97. Electrons emitted from the cathode 95-will become enabled, in response-to proper stimulation of the grid 93, to pass by the grid 93 to the anode"97-' of the tube' 58 of the member 89. The electrons will continue to travel in a stream from the anode 97, betweena pair of vertically disposed deflector plates 99 and 101, of '-wh ich the plate -99 is shown grounded, and between a pair of horizontally disposed deflector plates 103 and 105,-of which the plate 105 is shown grounded, to impinge finally on'the disc'9 of the member 89. A horizontal-sweep-time base, applied, as hereinaftermore fully-explained,'to' the vertically disposed deflector plates 99 and 101, will cause the'electrou stream from the cathode 95 to -become defiected horizontally, and a vertical-sweep-time base, applied to the horizontally disposed deflector plates 103 "and 105 will cause the electron-stream to become deflected vertically.

The before-described distance between the condenser plates may be made of value necessary to give the before-mentioned capacity, and the anode 97 may be adjusted so that this distance shall be substantially equal to the width of the electron stream, inorder that .the electron stream may fill the gap or 'regionxbetweeni'these condenser plates, thereby to discharge the condensers. The rows of condensers may be positioned. along the successive paths of theelectron stream, asthe electron stream" successively sweeps out'thesuccessive. rows of the array onthe disc "9.

It is not essential "that .the 'condenser plates'be embedded in the disc 9. They may be ordinary condensers,

connected in parallel with "rows and "columns of pinpoint electrodes (not 'shownyt hat are souembedded, arid separated from" each 'other'by the said di'stance in order that the electron stream of the member 89 may fill the gap between them. The electron stream will then electrically bridge the pin-point electrodes of each pair, to cause the discharge of the corresponding condenser.

The antenna sections of the array 7, and either the condensers in the disc 9, or the pairs of pin-point electrodes (not shown), will thus correspond to one another. A condenser is provided corresponding to each pick-up unit, and corresponding condensers or pairs of pin-point electrodes and pick-up antenna sections may occupy corresponding positions.

Radio-frequency voltages received through the lens 5 upon .the antenna-sections of :the array 7,, in the system of Fig. 1, are thus rectified, and there are built up across the corresponding condensers rectified-direct-current condenser-charging voltages that are proportional to the strengths of the radio-frequency voltages received by the corresponding antenna sections. As the electron stream produced'from'the cathode 95, in responsetoappropriate horizontal sweep-time-base voltages applied to the .vertically disposed deflector plates 99 and .101. of the cathode-ray-tube-like member .89, travels across between the condenser plates, --or ithe pairs of pin-point electrodes, in the disc 9, these built-up scharges upon the condensers become successively dischargedinto a grounded preferably linear amplifier 79, by way of -a-conductor -78. :If desired, the amplifier'79 may bereplaced by a bank of linear amplifiers, one corresponding to each of the antenna sections, and connected to the respective charging condensers.

The output of the amplifier 79 will obviously vary, at .successive instants, "in accordance with the discharge of the successive condensers, and this discharge is a measure of the strength of the radio energy-received by .the corresponding pick-up elements.

:A-pulsergeneraton'which may, if'desired, be the same pulse generator .4, maybe employed'to triggera horizontal-time-base-sweep circuit 63 and a vertical-sweep circuit :69,;accordingxto:conventional and well-known television technique. 'The pulse generator 4 .may feed, through an attenuator andrectifier l, to an oscillator or any similar or equivalent television circuit. One-such circuit is :shown as a pulse-recurrence-frequency multiplier 65, for applying .manytpulses corresponding to.each radio=frequency pulse for the period between successive radio pulses, .to trigger the horizontal-sweep circuit 63. A horizontal-time-basesweep will thereby be: produced be- ..tween'theivertically disposed defiectorplates .99 and-101, occurringas manystimesysay, between successive'radiofrequency: transmissions, as' there. are rowsof pick-up antennae. The pulse generator 4 may also feed, through the attenuator andrectifierll, to trigger the vertical-sweep :circuit =69, .onee corresponding .to every radio-frequency transmission. -One vertical sweep will then occur between -thefhorizontally disposed plates 103, 105, during the IPBIlOdS' between successive radio-pulse transmissions, corresponding to as -many horizontal sweeps as there are -rows=xof.- antennae, causing eachof the horizontal sweeps .to appear at successively lower levels on the oscilloscopesweep. faces.

5 If the circuiti65 comprisesan oscillator, the oscillations mayubeemployed to trigger the horizontalsweep. The .periodai-ofi the oscillations which,- as before explained, is much less than the duration of a radio pulse, corre- -tsponds to the time of dischargeof one row of the con- .densers: int-he disci 9, in response to energization of one row'ofwthe antenna sections of the array 7. If, as pre- IYIOUSIY mentioned, continuous-waveradio transmission employed;the-vertical sweep circuit 69 may be triggered ltonproduce'one vertical sweep corresponding to many horizontal sweeps from the horizontal-sweep :crrcuit \63 -as' there" are 1 rows ofantenna sections.

Means is provided, controlled 'by the discharge of the condensers, for-producing, upon the screen 1 06 of the display oscilloscope 1: 90, images corresponding to the radio-frequency energyreceived'by the correspond ing pick-up antenna elements. successively disposed areas-of the fiuorescentscreen '106, that correspond-to the similarly disposed antennaelements,are-energized by an*electron-strea-min the oscilloscope to illuminate them. This electron stream is synchronized to travel with the electron stream of the cathodewray-tube-like "member89. The' ho rizontal sweep circuit 63 .is connected to the horizontal-dcflejctor plate 1100.,of the .os-

cilliscope'90 by a conductor '67, and to 'the horizontal deflector plate 101 of the oscilloscope-like member 89 by the conductor 67 and a conductor 124. The verticalsweep circuit 69 is connected to the vertical-deflector plate 102 of the oscilloscope 90 by a conductor 71, and to the vertical-deflector plate 103 of the oscilloscope-like member 89 by the conductor 71 and a conductor 146.

The amplifier 79 is connected by conductors 84 and 86, to the phase-inverter and amplifier stage or stages 81 which, in turn, is connected, by conductors 85 and 87, to the control-grid electrode 92 and the cathode 94 of the vacuum-tube electron-gun part 88 of the oscilloscope 90. The condensers become thus successively connected, through the amplifier 79 and the phase-inverter 81, to the control electrode 92. Electrons emitted from the cathode 94 will become enabled, in response to the action of the amplifier 79 and the phase-inverter 81, to pass by the grid 92, to the anode 96 of the tube 88 of the oscilloscope tube 90. The electrons will continue to travel in a stream from the anode 96, between the pair of vertically disposed oscilloscope deflector plates 98 and 100, of which the plate 98 is shown grounded, and between the pair of horizontally disposed oscilloscope deflector plates 102 and 104, of which the plate 104 is shown grounded, to impinge finally on the fluorescent viewing screen 106 of the oscilloscope 90. The horizontal-sweep-time base applied to the vertically disposed deflector plates 98 and 100 will cause the electron stream from the cathode 94 to become deflected horizontally, and the vertical-sweep-time base, applied to the horizontally disposed deflector plates 102 and 104, will cause the electron stream to become deflected vertically, in synchronism with the horizontal and vertical sweeps discharging the condensers in the disc 99 of the scope-like member 89.

The magnitude of the voltage fed into the amplifier 79 from the condensers will depend upon the intensity of the radio-frequency voltage received from the object 8 through the lens by the corresponding antenna sections. This is because the sections are successively rendered effective by the discharging of the corresponding condensers by the electron stream of the member 89. The output of the amplifier 79 will therefore vary, at successive instants, in accordance with the potential upon the successive receiving antenna sections. Successive energizing positive voltages are thus produced from the amplifier 79 on the control electrode 92 of the tube part 88 of the cathode-ray tube 90, of magnitude proportional to the radio-frequency energy received by the corresponding antenna sections. This will render the tube 90 effective to permit the passage of the electrons in quantities dependent upon the radio-frequency energy impinging on the particular antenna section, to the anode 96, and between the pairs of vertically disposed deflecting plates 98, 100 and horizontally disposed deflecting plates 102, 104, to the viewing screen 106.

After each simultaneous horizontal sweep of both the scope 90 and the oscilloscope-like member 89 has been completed, a successively larger voltage will be applied to the horizontally disposed deflector plates 103, 105 and 102, 104, respectively, by the vertical sweep circuit.

. After the last such horizontal sweep, the voltage between the horizontally disposed plates 103, 105 and 102, 104

v will become restored to zero. The next horizontal sweep,

therefore, will start again at the first or top row.

Successively disposed areas of the screen 106 of the oscilloscope 90 will therefore correspond to the similarly disposed condensers in the disc 9 of the oscilloscopelike member 89, and to similarly disposed antenna sections. Each spot along a particular horizontal sweep, therefore, will become brightened on the screen 106 according to the amount of radio energy received by the corresponding pick-up element, and fed, by way of the amplifier 79 and the phase-inverting-and-amplifying circuit 81, to the control electrode 92 of the tube 88 of the cathode-ray oscilloscope 90 to render the tube 90 effective to produce a likeness upon the screen 106.

To each row of antenna sections, therefore, there corresponds, on the face 9 of the oscilloscope-like member 89, a horizontal electron stream that discharges the horizontal row of charged condensers. To each row of antenna sections, moreover, there corresponds, on the oscilloscope screen 106, a horizontal electron stream that is graded in intensity, due to the application of signal voltages, from successive antenna sections of the row, on the oscilloscope control-grid electrode 92. This intensity is distributed in synchronism with the corresponding state of charge of the corresponding condensers on the disc 9 of the scope-like member 89. This provides for successive horizontal time bases on the screen, and the successive areas of the screen 106 are thus illuminated in synchronism with the effective reception of the radio energy by the corresponding pick-up antenna sections. To each successive row of antenna sections, moreover, there corresponds a successively lowered level of operation of the electron stream on the screen 106 ofthe oscilloscope, corresponding to the measured voltage applied at that instant by the vertical sweep circuit 69.

The sweeps of the two electron streams of the members 89 and are thus synchronized, to produce intensity modulation on the oscilloscope screen 106, corresponding to the radio-frequency distribution on the antenna sections of the bank 7. The radio waves received successively by the antenna units along the successive rows and columns will thus become converted into successive portions of the visual likeness .123, along correspondingly disposed rows and columns thereof, along the successive time bases. The visual picture 123 of the aircraft object 8 on the oscilloscope screen 106 will accordingly correspond to the radio-frequency picture on the array 7 of pick-up elements which, in turn, corresponds to the actual object 8.

If the rectifiers 13, 17, etc., are not used, as previously suggested, but radio-frequency voltages are applied directly to the condenser plates 28, 30, 32, 34-, 36, 38, 40, 42, 44, etc., then slight modifications may be incorporated as follows: the amplifier 79 and its input should be tuned to the radio-frequency energy that will be fed thereto during the scanning of the condenser, and the phase-inverter-and-amplifying stage or stages 81 should be followed by a rectifier (not shown), and then applied to the control grid 92 of the cathode-ray oscilloscope 90.

Instead of the conducting antenna sections of the array 7, other types of conventional ultra-high-frequency antenna units may be employed such, for example, as the hollow-pipe valve-guides illustrated in Fig. 2. Square-cross-sectional wave-guides are there shown, designated by the same reference numerals as the corresponding conducting antenna sections of Fig. 1, but agumented by 100. Each wave-guide is provided with a pick-up loop that is connected, through the corresponding rectifier, to the corresponding condenser. Thus, the wave-guide 110 is provided with a pick-up 111 that is connected by the conductor 11, through the rectifier 13, to the condenser 28, 35; the wave-guide 112 is provided with a pick-up loop 115 that is connected by the conductor 15, through the rectifier 17, with the condenser 30, 37; the wave-guide 114 is provided with a pick-up loop 119 that is connected by the conductor 19,

through the rectifier 21, with the condenser 32, 39;

and so on. The operation is substantially the same as before described, with the condensers connected to feed the amplifier 79, except that there is less need for feedtransmission lines and, therefore, less attenuation of the high-frequency energy. The wave-guides will, of course, have dimensions suitable for receiving the desired wave which, as before stated, may have a length of 3 or 1.5 centimeters.

Assuming that the size of the object 8 is known, the position of the lens 5 to produce a sharp electromagnetic image on the array 7 of dipoles, coupled with the size of the visual image 123, may be used to deduce range, by simple geometrical optics. If, for example, the object seen is a fighter, or a bomber plane, the size of the image, divided by the known size of the fighter or bomber, will be proportional to the ratio between the distance of the lens 5 from the bank 7 of antennae, adjusted to obtain clear vision, divided by the distance of the object 8. The range of the object 8 may also easily be obtained by monitoring the pulse emission and reflection, if radio pulses are used, on a separate oscilloscope, according to common practice.

Although the invention has been described in connection with antennae arranged in rows and columns, it will be understood that this is not essential, for other arrangements are also possible. Antennae arranged along concentric circles covering the field, or a continuous spiral, will also serve, though the oscilloscope arrangement would, of course, be correspondingly modified. In the case of the concentric circles and the spiral, the an- 7 tennae would be rendei'ed efiective in twoqiimensional order, asin the ease of the rows and columns before described; The antennae disposed along one of the circles, for example, would first be rendered effective, then those along the next circle, and so on.

Further modifications will occur to persons skilled in the art, and all such are considered to fall within the spirit and scope of the invention, as defined in the appended claims.

What is claimed is:

1. An electric system having, in combination, a plurality of radio-receiving wave-guide elements, a plurality of antennae associated with the wave-guide elements, a plurality of condensers, one corresponding to each of the antennae, means for charging each condenser from the energy of the corresponding antenna, means for successively discharging the condensers, and means controlled by the discharge of each condenser for producing a likeness corresponding to the energy received by the corresponding element.

2. An electric system having, in combination, a cathode-ray-tube-like member having an electron-stream-producing means and a screen, a plurality *of energy-storing means supported by the screen and each provided with a pair of oppositely disposed electrodes separated from 1 one another, and means for causing the electron stream to fill the separated regions between the electrodes, thereby to discharge the energy storing means.

3. An electric system having, in combination, a plurality of radio-receiving elements, a plurality of electrical charging elements, rectifying means, means connecting the charging elements to the receiving elements through the rectifying means to energize the charging elements from the energy of the receiving elements, means for successively discharging the charging elements, and means controlled by the discharge of each charging element for producing a likeness corresponding to the energy received by the corresponding receiving element.

4. An electric system having, in combination, a plurality of radio-receiving elements, a plurality of electrical charging elements, one corresponding to each of the radio receiving elements, a plurality of rectifiers, one corresponding; to each of the electrical charging elements, means connecting the charging elements to the respective receiving elements through the respective rectifiers to energize the charging elements from the energy of the corresponding receiving elements, means for successively discharging the charging elements, and means controlled by the discharge of each charging element for producing a likeness corresponding to the energy received by the corresponding receiving element.

5. An electric system having, in combination, a twodimensional array of wave-guide radio-receiving elements arranged in rows and columns for receiving radio waves from an object, a two-dimensional array of electrical charging elements arranged in rows and columns, one corresponding to each of the receiving elements, means for charging each charging element from the energy of the corresponding receiving element, means for scanning the charging elements in two-dimensional order along the rows and columns thereof successively to discharge the charging elements in two-dimensional order along the successive rows and columns, a normally inefiective electric circuit for producing a likeness corresponding to the radio energy received by the receiving elements from the object, means for connecting the charging elements to the circuit, and means controlled in 'synchronism with the successive discharges of the charging elements for rendering the circuit successively effec- 8 tive through the connecting means to produce successive portions of the likeness of the object in two-dimensional order along rows and columns corresponding to the rows and columns of the charging elements synchronously with the reception of the radio energy from the object by the corresponding receiving element.

6. An electric system having, in combination, a twodimensional array of wave-guide radio-receiving elements for receiving radio waves from an object, a two-dimens'ional array of electrical charging elements, one corresponding to each of the receiving elements, means for charging each charging element from the energy of the corresponding receiving element, means for sending an electron stream to the charging elements in two dimensional order successively to discharge the charging elements in two-dimensional order, an amplifier for amplfying the discharges of the charging elements, means for connecting the charging elements to the amplifier, an oscilloscope having a screen successively disposed areas of which correspond to the successively disposed receiving elements in two-dimensional order and means for producing an electron stream impinging on the screen, and means connected to the amplifier for controlling the operation of the oscilloscope electron stream in synchronism with the operation of the discharging electron stream to produce successive portions of a likeness of the object along the said areas of the screen in two-dirhensional order synchronously with the reception of the radio energy from the object by the receiving elements corresponding to the said areas.

'7. An electric system as claimed in claim 2 and in which there is provided radio-frequency means for energizing the energy-storing means.

8. An electric system as claimed in claim 2 and in which there is provided radio-frequency antenna means for energizing the energy-storing means.

9. An electric system as claimed in claim 2 and in which there is provided radio-frequency wave-guide means for energizing the energy-storing means.

10. An electric system as claimed in claim 2 and in which there are provided radio-frequency means, rectifying means, and means for energizing the energy-storing means from the radio-frequency means through the rectifying means.

References Cit-ed in the file of this patent UNITED STATES PATENTS Number Name I Date 1,699,270 Baird Jan. 15, 1929 2,010,543 Gray Aug. 6, 1935 2,058,898 Mathes Oct. 27., 1936 2,083,292 Cawley June 8, 1937 2,103,481 Mathes Dec. 28, 1937 2,219,113 Ploke Oct. 22, 1940 2,230,295 Holmes Feb. 4, 1941 2,234,328 Wollf Mar. 11, 1941 2,265,216 Wolf Dec. 9, 1941 2,273,172 1942 2,306,272 Levy Dec. 22, 1942 2,429,933 Gibson Oct. 28, 1947,

FOREIGN "PATENTS Number Country Date 541,959 Great Britain Dec. 19, 1941 OTHER REFERENCES Television Standards and Practice, N. T. S. C., ]3)6o2nald G. Fink, McGraw-Hill Book Co., Inc, 1943, p.

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