About: Hedy Lamarr

Hedy Lamarr

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United States Patent Office 2,292,387 Secret Communication System Hedy Kiesler Markey, Los Angeles, and George Antheli, Manhattan Beach, Calif. Application June 10, 1941, Serial No. 307,412 6 Claims. (CI. 250-2) This invention relates broadly to secret communication systems involving the use of carrier waves of different frequencies, and is especially useful in the remote control of dirigible craft, such as torpedoes.
An object of the invention is to provide a method of secret communication which is relatively simple and reliable in operation, but at the same time is difficult to discover or decipher.
Briefly, our system as adapted for radio control of a remote craft, employs a pair of synchronous records, one at the transmitting station and one at the receiving station, which change the tuning of the transmitting station, which change the tuning of the transmitting and receiving apparatus from time to time, so that without knowledge of the records an enemy would be able to determine at what frequency a controlling impulse mine at what frequency a controlling impulse would be sent. Furthermore, we contemplate employing records of the type used for many years in player pianos, and which consist of long rolls of paper having perforations variously positioned in a plurality of longitudinal rows along the records. In a conventional player piano record there may be 88 rows of perforations, and in our system such a record would permit the use of 88 different carrier frequencies, from one to another of which both the transmitting and receiving station would be changed at intervals. Furthermore, records of the type described can be made of substantial length and may be driven slow or fast. This makes it possible for a pair of records, one at the transmitting station and one at the receiving station, to run for a length of time ample for the remote control of a device such as a torpedo.
The two records may be synchronized by driving them with accurately calibrated constantspeed spring motors, such as are employed for driving clocks and chronometers. However, it is also within the scope of our invention to periodically correct the position of the record at the receiving station by transmitting synchronous impulses for correcting the phase relation of rotary apparatus at a receiving station is well-known and highly developed in the fields of automatic telegraphy and television.
Other more specific objects and features of our invention will appear from the following detailed description of a particular embodiment thereof, as illustrated in the drawings, which in Fig. 1 is a schematic diagram of the apparatus at a transmitting station;
Fig. 2 is a schematic diagram of the apparatus at a receiving station;
Fig. 3 is a schematic diagram illustrating a starting circuit for starting the ,motors at the transmitting and receiving stations simultaneously;
Fig. 4 is a plan view of a section of a record strip that may be employed;
Fig. 5 is a detail cross section through a record-responsive switching mechanism employed in the invention;
Fig. 6 is a sectional view at right angles to the view of Fig. 5 and taken substantially in the plane VIVI of Fig. 5, but showing the record strip in a different longitudinal position; and
Fig. 7 is a diagram in plan illustrating how the course of a torpedo may be changed in accordance with the invention.
Fig. 3 is a schematic diagram illustrating a starting circuit for starting the ,motors at the transmitting and receiving stations simultaneously;
Fig. 4 is a plan view of a section of a record strip that may be employed;
Fig. 5 is a detail cross section through a record-responsive switching mechanism employed in the invention;
Fig. 6 is a sectional view at right angles to the view of Fig. 5 and taken substantially in the plane VIVI of Fig. 5, but showing the record strip in a different longitudinal position; and
Fig. 7 is a diagram in plan illustrating how the course of a torpedo may be changed in accordance with the invention.