April 17, 1951 D. W. EPSTEN 2,549,072 RECORDING APPARATUS FOR RADAR SYSTEMS Filled Feb. 27, l946 2 Sheets-Sheet raerezerezprzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz! ? INVENTOR. VIZAŽorzeiz7. 4 Z7ZJAPAVEV. April 17, 1951 D. W. EPSTEIN 2,549,072 RECORDING APPARATUS FOR RADAR SYSTEMS Filed Feb. 27, 1946 2 Sheets-Sheet 2 AZAM/AAM7S 774/vsaaatzW7 4.74744 /?Z/? z INVENTOR. A27/žazº VZ Av/ein BY C94. 4772A Patented Apr. 17, 1951 2,549,072 UNITED STATES PATENT OFFICE 2,549,072 RECORONG APPARATUS FOR RADAR SYSTEMIS David W. Epstein, Princeton, N. J., assignor to Radio Corporation of America, a corporation of Delaware Application February 27, 1946, Seria No. 650,708 3 Claims. (C. 250-50) - My invention relates to signal receiving Systems the following description taken in connection wherein images produced on luminescent Screens with the accompanying drawing in which or the like are transferred to the storage Screen Figure 1 is a block and circuit diagram of the of a cathode ray tube. invention as applied to a radar system, The present invention is particularly applicable Figure 2 is an enlarged view in cross section to systems wherein a radar picture is produced of the screen used in the cathode ray tube shown on a luminescent screen and wherein it is de in Fig. 1 of the drawing, sired to transmit the radar picture to a remote Figure 3 is a view in cross section of another point by utilizing a cathode ray storage tube. embodiment of a screen that may be used in the It has previously been proposed to project Such () cathode ray tube of Fig. 1, and . a radar picture upon a storage Screen by means Figure 4 is a view of the screen of Fig.1 sepa. of a lens system. An arrangement of this kind rated into two portions for the purpose of illus is described and claimed in application Serial No. trating the scanning paths of the cathode rays 500,739, filed August 30, 1943 in the name of in the cathode ray tube of Fig.1. Irving Wolff and entitled Recorder for Radio Lo Fig. 1 shows a pulse-echo radar System corn. cator now Patent No. 2,415,981 issued February prising a radio transmitter that is pulse modu 18, 1947. A serious disadvantage of the Wolff lated by pulses supplied from a pulse generator arrangement is that even with a good lens Sys through a delay network 2 and a pulse keyer or tem a large amount of light is lost with the re modulator 3. The transmitter antenna, 5 may suit that it is sometimes difficult to transmit a 20 be non-directive. Pulses from generator are radar picture properly even though it is clearly also supplied over a conductor 4 to a Sawtooth visible on the luminescent Screen. wave generator 6. The purpose of the delay An object of the present invention is to pro network 2 is to insure that any irregularity at vide an improved method of and means for trans the start of the sawtooth Wave will have ended by mitting a radar picture whereby the above-men 25 the time a reflected pulse is received. tioned difficulty is avoided. The particular radar system illustrated is de A further object of the invention is to provide signed to locate and record reflecting objects lo an improved method of and means for trans cated to the left and to the right of the radar sys ferring a picture from a luminescent screen or tem. For example, the apparatus illustrated may the like to a storage Screen. be carried by an aircraft and used for locating A still further object of the invention is to pro ships at sea. The receiving apparatus comprises vide an improved screen structure for cathode directive antennas and 8 pointing to the left ray tubes. and right, respectively, of the aircraft's line of A still further object of the invention is to flight. Reflected pulses picked up by the antennas. provide an improved cathode ray tube having and 8 are supplied to separate radio receivers signal put-on and signal take-off sections. f8 and 21, respectively, which detect and amplify A still further object of the invention is to the received signals. : . provide an improved radar system that is de The Video frequency pulses appearing in the signed to record the received radar information. receiver output circuits are supplied through According to a preferred embodiment of the blocking capacitors 22 and 23 to the control grids invention, I provide a double cathode ray tube 24 and 26, respectively, of a double gun section that comprises a Cathode ray receiving tube Sec of a cathode ray tube 2. - tion or signal put-on section and a cathode ray The cathode ray tube 27 comprises two sections, storage tube section or signal take-off section. A one section being the above-mentioned double single screen structure is provided for the two gun section which produces two cathode rays. tube sections. The screen structure comprises a which are directed against aluminescent screen storage Screen that faces the storage tube sec such as a phosphorescent screen surface 28, and tion and a phosphorescent screen that is in con the other section being a storage tube section hay tact with the side of the storage screen facing ing one electron gun that directs a cathode ray the receiving tube section. Because the phos- : against a storage screen surface 29. The double phorescent Screen and the storage screen are in gun section is the signal put-on section and the contact with each other, there is no necessity storage tube section is the signal take-off sec for a lens System to project or form the phos tion. phorescent screen picture on the storage screen. The double gun section of the tube 27 includes The invention will be better understood from 55 one electron gun that consists of a cathode 3!, 2,549,072 3 4 the grid 24, and first and Second anodes 32 and Screen 28 is transferred to and stored on the 33, respectively, for producing an electron beam Screen 29 without the use of a lens system and, indicated at 30. This section also includes a sec therefore, without the large loss of light intro Ond electron gun that consists of a cathode 34, duced by a lens system. It may be noted that the grid 26, and first and Second anodes 36 and the phosphorescent Screen 28 might be replaced, 37, respectively, for producing an electron beam for example, by a screen of the type that has an indicated at 35. The Second anodes 33 and 37 are image formed thereon by the heating effect of the connected to a conductive envelope coating 38 bombarding electrons of the scanning beam, Which is grounded. Suitable Operating Voltages Such an image could be either a visible image or for the cathodes and first anodes are indicated an invisible image Such as an infrared ray merely by Way of example. image. Wertical defecting plates 4 and horizontal de Referring again to Fig. 1, suitable voltages for flecting plates 42 are provided for deflecting the the electrodes of the storage tube section have electron beam 3. Likewise, vertical deflecting been indicated merely by way of example. A plates 43 and horizontal deflecting plates 44 are horizontal Scanning current of triangular Wave provided for deflecting the electron beam 35. form is Supplied to the deflecting yoke 58 from A high frequency sine WaWe OScillator AS Sup any Suitable Source such as the rotating arm 6 plies defiecting voltage to the vertical deflecting of a potentiometer resistor 62 that is supplied plates is and 43 so that the electron beams 3G With current from a battery 63. The potentiom and 35 will make a comparatively wide spot or 2) eter arm 6 l is driven by a motor 64 in Synchro bar of light on the screen 23 when reflected nism. With the Scanning drum 66 of the recorder pulses are received. A8. The Sawtooth voltage wave fron the generator A vertical deflecting current for shifting the S is Supplied to the horizontal deflecting plates electron beam 49 up and down is supplied to the A2 and Si So that the electron beams 3 and 35 5 deflecting yoke 58 from a battery 67 by way of are defected along a tine axis which may be cali a cam operated switch 68. The cam 69 for op brated in terms of distance to the refecting ob erating the Switch 68 is driven in Synchronism jects. With the potentiometer arm 6 as indicated by Fig. 4 illustrates the appearance of a radar pic the broken line 7 ?. Preferably, a high frequency ture on the Screen. 28. In this instance, the spots 3) sine Wave current is also Supplied from an oscil--- or bars A and B represent two ships or other re lator 12 to the deflecting yoke for widening the flecting objects to the right of the airborne radar line along which the cathode ray 49 scans. equipment while the Spot C represents a ship to The method of taking the stored signal of the the left of Said radar equipment. By means of Storage Screen 29 by the Scanning beam 49 is the the storage tube section of the tube 27, the spots : Same as that previously employed in the Orthi A, B and C are recorded on the tape A of a COn. AS indicated by the broken line 75, as the facsimile recorder 48 as described hereinafter.