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    "localId": "486498244",
    "label": "Report, OSI - 10-50, Central Intelligence Agency, Soviet Guidance and Control Development Particularly as Applied to Guided Missiles",
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    "contentType": "document",
    "title": "Report, OSI - 10-50, Central Intelligence Agency, Soviet Guidance and Control Development Particularly as Applied to Guided Missiles",
    "citationUrl": "https://catalog.archives.gov/id/486498244",
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        "President's Secretary's Files (Truman Administration)",
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{
    "seq": 67,
    "pageIndex": 0,
    "type": "photo",
    "url": "https://s3.us-east-1.amazonaws.com/NARAprodstorage/lz/presidential-libraries/truman/hst-psf/602196/875492/875492-02-067.tif",
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    "ocrText": "TOP SECRET\nENCLOSURE 2, CHAPTER II\n1. STRASSBURG-KEHL SYSTEM\nThe following account of the Strassburg-Kehl radio control system is written in\nvery general terms since circuit diagrams of the various components as well as other\npertinent data on their size, weight, etc., can be readily obtained from such papers as the\nU.S. Naval Technical Mission in Europe, Report No. 158-45 (September 1945): Electronics\nAS Applied TO German Guided Missiles. Much of the material below is condensed from\nthat report.\nIn the year 1939, Dr. Spath of the Experimental Institution at Peenemuende devel-\noped a small gliding body. At the same time an order was issued by the Luftwaffe to the\nStassfurter Rundfunk Gesellschaft to design and construct suitable radio control equip-\nment to be used with this glide bomb.\nIn September and October of 1939, Stassfurter Rundfunk began planning the\nMaander Verfahren, a square-wave form control system. By means of four separate\nmodulation frequencies in the audio range, it was proposed to obtain proportionate control\nfor two pairs of coordinates, up-down and left-right. One pair of tones would give up-\ndown information and the other pair of tones left-right information. The graduated or\nproportionate control was to be obtained by sharing the time duration between tone pairs\nover a fixed interval and repeating the interval. For example, the interval might be 0.1\nsecond and alternating periods of 1 kc for Up and 1.5 kc for Down of 0.05 second each\nwould result in neutral control. However, if the time duration of the 1-kc tone was reduced\nto 0.025 second and the time duration of the 1.5-kc tone was increased to 0.075 second\nin each 0.1-second interval a down command equal to 50 percent of the maximum command\ncould be transmitted. The choice of this system in preference to amplitude or frequency\nmodulation for obtaining proportionate control represented a fundamental consideration.\nIt was decided that the greatest accuracy could be achieved by a method based on time\ndifferences and not dependent on amplitude or frequency variations.\nIn November, 1939, the initial development of the FX high angle bomb was essen-\ntially complete. Since the spoiler system of the FX represented a black and white type\nof control, it soon became apparent that the square-wave form control system, Maander\nVerfahren, was almost ideally suited to this application since it was, in a sense, a black\nand white type of radio control. Furthermore, it was felt that its versatility was such\nthat it could still be used for all proportionate control applications Work was therefore\nintensified on this system. In order to distribute the work, Telefunken was to design the\ntransmitter and Stassfurter Rundfunk the receiver and control circuits. By June of 1940\nthe 50-mc transmitter S-203 (Kehl) and the superheterodyne receiver E 30 (Strassburg)\nwere completed. The tone frequencies used were 1, 1.5, 8, and 12 kc. The FX develop-\nment was delayed due to unsatisfactory gyro arrangement and so the radio control\nequipment was not used at that time.\nDuring the development of the Strassburg-Kehl system, the possibility of trans-\nmitting only one frequency for each pair of coordinates was considered. In other words,\ninstead of sharing the time interval between two tones, it would be shared between one\ntone and the absence of modulation. Consideration. of jamming possibilities led to drop-\nping this method in favor of the four tones, which required more power for a jamming\ntransmitter. In addition, it was determined that accuracy of the transmitted command\nwas greater in the case of the four tones.\nBy December 1940 progress on the FX and Hs-293 air-to-surface missiles was\nsuch that large-scale production was planned and so improved models of the Strassburg-\nKehl were worked on. The receivers E 30b and E 230 on a frequency of 50 Mc were devel-\noped by the end of 1942. These were superheterodyne receivers containing both AVC and\nTOP SECRET\n58"
}