Radio frequency coding system

• US 3,945,006 A
• Filed: 04/04/1952
• Issued: 03/16/1976
• Est. Priority Date: 04/04/1952
• Status: Expired due to Term

• Current Assignee: the united states of america as represented by the secretary of the navy
• Original Assignee: the united states of america as represented by the secretary of the navy
• Inventors: Cleeton, Claud E.
• Primary Examiner(s): Tubbesing, T. H.
• Application Number:
  US03/280,634
• Time in Patent Office: 8,747 Days
• Field of Search: 343/6, 343/6.5, 343/6.8, 343/227, 343/6 R, 343/6.5 R
• US Class Current: 342/45
• CPC Class Codes: G01S 13/782 using multimoding or selective addressing

Abstract

2. In combination, a radar locator system, a pulse generator operable to duce pulse transmissions comprising one or more time spaced pulses occurring in any of a plurality of fixed time positions to form a plurality of different pulse code patterns which vary from pulse transmission to pulse transmission, a receiving means for receiving each of said pulse transmissions, a coder circuit in said receiving means responsive to the number and time position of said pulses to generate a reply signal having a characteristic dependent upon the pattern of said pulse transmissions, means for synchronizing the operation of said radar locator system and said pulse generator, and means for correlating the reply signals generated in said coder circuit and the echo pulses received by said radar locator system.

Claims

1. In combination, a pulse generator operable to produce pulses transmissions comprising one or more time spaced pulses occurring in any of a plurality of fixed time positions to form a plurality of different pulse code patterns which vary from pulse transmission to pulse transmission, a receiving means for receiving each of said pulse transmissions, and a coder circuit in said receiving means responsive to the number and time position of said pulses to generate a reply signal having a characteristic dependent upon the pattern of said pulse transmissions.

2. In combination, a radar locator system, a pulse generator operable to produce pulse transmissions comprising one or more time spaced pulses occurring in any of a plurality of fixed time positions to form a plurality of different pulse code patterns which vary from pulse transmission to pulse transmission, a receiving means for receiving each of said pulse transmissions, a coder circuit in said receiving means responsive to the number and time position of said pulses to generate a reply signal having a characteristic dependent upon the pattern of said pulse transmissions, means for synchronizing the operation of said radar locator system and said pulse generator, and means for correlating the reply signals generated in said coder circuit and the echo pulses received by said radar locator system.

3. In combination, a first pulse transmission means for producing a plurality of different code patterns which patterns vary transmission to transmission, a first coder circuit coupled to said transmission means and adapted to generate a coded signal dependent upon pulse signals transmitted by said transmission means, a receiving means tuned to said first transmission means to receive each of the transmitted code patterns, a second coder circuit coupled to said receiving means and adapted to generate in response to the energy received from the first transmission means a coded signal identical to that generated by said first coder circuit, a second transmission means coupled to said second coder circuit and adapted to transmit the specific coded signal generated by said second coder circuit.

4. In combination, a first pulse transmission means, a first coder circuit coupled to said transmission means and adapted to generate a coded signal dependent upon pulse signals transmitted by said transmission means, a first receiving means tuned to said first transmission means, a second coder circuit coupled to said first receiving means and adapted to generate in response to the energy received from the first transmission means a coded signal identical to that generated by said first coder circuit, a second transmission means coupled to said second coder circuit and adapted to transmit the specific coded signal generated by said second coder circuit, a second receiving means tuned to said second transmission means, and a comparing means coupled to the second receiving means and the first coder circuit for comparing the coded signals received by said second receiving means and those generated by said first coder circuit.

5. In combination, a pulse generator operable to produce pulse transmissions comprising one or more time spaced pulses occurring in any of a plurality of fixed time positions to form a plurality of differenti pulse code patterns, receiving means for receiving said pulse transmissions, and a coder circuit in said receiving means responsive to the number and time position of said pulses to generate a reply signal having a frequency dependent upon the pattern of said pulse transmissions.

6. In combination, a pulse generator operable to produce pulse transmissions comprising one or more time spaced pulses occurring in any of a plurality of fixed time positions to form a plurality of different pulse code patterns, receiving means for receiving said pulse transmissions, and a coder circuit in said receiving means responsive to the number and time position of said pulses to generate a reply signal having a time delay dependent upon the pattern of said pulse transmissions.

7. In combination, a radar locator system, a pulse generator operable to produce pulse transmisions comprising one or more time spaced pulses occurring in any of a plurality of fixed time positions to form a plurality of different pulse code patterns, receiving means for receiving said pulse transmissions, a coder circuit in said receiving means responsive to the number and time position of said pulses to generate a reply signal having a frequency dependent upon the pattern of said pulse transmissions, means for synchronizing the operation of said radar locator system and said pulse generator, and means for correlating the reply signals generated in said coder circuit and the echo pulses received by said radar locator system.

8. In combination, a radar locator system, a pulse generator operable to produce pulse transmissions comprising one or more time spaced pulses occurring in any of a plurality of fixed time positions to form a plurality of different pulse code patterns, receiving means for receiving said pulse transmissions, a coder circuit in said receiving means responsive to the number and time position of said pulses to generate a reply signal having a time delay dependent upon the pattern of said pulse transmissions, means for synchronizing the operation of said radar locator system and said pulse generator, means for correlating the reply signals generated in said coder circuit and the echo pulses received by radar locator system.

9. In combination, a pulse generator operable to produce pulse transmissions comprising one or more time spaced pulses occurring in any of a plurality of fixed time positions to form a plurality of different pulse code patterns which vary from pulse transmission to pulse transmission, a receiving means for receiving each of said pulse transmissions, a coder circuit in said receiving means responsive to the number and time position of said pulses to generate a reply signal having a characteristic dependent upon the pattern of the received pulse transmissions, a second receiving means for receiving said reply signal, and utilization means coupled to said second receiver for utilizing the output derived therefrom.

10. In combination, a pulse generator located at a first point and operable to produce pulse transmissions comprising one or more time spaced pulses occurring in any of a plurality of fixed time positions to form a plurality of different code patterns, a receiving system located at a second point for receiving said pulse transmissions, a coder circuit in said receiving system operative responsive to the number and time position of said pulses to generate a coded reply signal having signal characteristics depending upon the pattern of said pulse transmissions, a reply signal receiver at first point, a second coder circuit at said first point coupled to said reply signal receiver and responsive to the code pattern transmitted by said pulse generator to render said reply signal receiver sensitive to receive the reply signal.

11. In combination, a pulse generator located at a first point and operable to produce pulse transmissions comprising one or more time spaced pulses occurring in any of a plurality of fixed time positions to form a plurality of different code patterns, a receiving system located at a second point for receiving said pulse transmissions, a coder circuit in said receiving system operative responsive to the number and time position of the received pulses to generate a coded reply signal having signal characteristics depending upon the pattern of said pulse transmissions, a reply signal receiver at said first point, a second coder circuit at said first point coupled to said reply signal receiver and responsive to the code pattern transmitted by said pulse generator to render said reply signal receiver sensitive to receive the reply signal, and utilization means coupled to the output of said reply signal receiver for utilizing the output derived therefrom.

12. In combination, a radio echo detection system comprising a transmitter for transmitting periodic energy pulses, a receiver for receiving said periodic energy pulses after reflection from remote objects and a cathode ray indicator for indicating in two space coordinates the position of the various objects detected by the system, a recognition system synchronized with said radar system and comprising an interrogator pulse transmitter at the radar site for periodically transmitting into space one or more time spaced pulses occurring in any of a plurality of fixed time positions to form a plurality of different code patterns, a recognition receiver system adapted for installation aboard friendly objects for receiving said pulse patterns, a coder circuit in said recognition receiver system for generating a reply signal having signal characteristics in dependency upon the pulse pattern received, a reply receiver at the radar site, a second coder circuit at the radar site coupled to said reply receiver and responsive to the code pattern transmitted by said pulse generator to render said reply receiver sensitive to receive the reply signal, and means for applying the output of the reply receiver to said cathode ray indicator.

13. In combination, a radio echo detection system comprising a transmitter for transmitting periodic energy pulses, a receiver for receiving said periodic energy pulses after reflections from remote objects and a cathode ray indicator for indicating in two space coordinates the position of the various objects detected by the system, a recognition system synchronized with said radar system and comprising an interrogator pulse transmitter at the radar site for periodically transmitting into space one or more time spaced pulses occurring in any of a plurality of fixed time positions to form a plurality of different code patterns, a recognition receiver system adapted for installation aboard friendly objects for receiving said pulse patterns, a coder circuit in said recognition receiver system for generating a reply signal having a carrier frequency in dependency upon the pulse pattern received, a reply receiver at the radar site, a second coder circuit at the radar site coupled to said reply receiver and responsive to the code pattern transmitted by said pulse generator to tune said reply receiver to receive the reply signal.

14. In combination, a radio echo detection system comprising a transmitter for transmitting periodic energy pulses, a receiver for receiving said periodic energy pulses after reflections from remote objects and a cathode ray indicator for indicating in two space coordinates the position of the various objects detected by the system, a recognition system synchronized with said radar system and comprising an interrogator pulse transmitter at the radar site for periodically transmitting into space one or more time spaced pulses occurring in any of a plurality of fixed time positions to form a plurality of different code patterns, a recognition receiver system adapted for installation aboard friendly objects for receiving said pulse patterns, a coder circuit in said recognition receiver system for generating a reply signal having a carrier frequency in dependency upon the pulse pattern received, a reply receiver at the radar site, a second coder circuit at the radar site coupled to said reply receiver and responsive to the code pattern transmitted by said pulse generator to tune said reply receiver to receive the reply signal, and means for applying the output of the reply receiver to said cathode ray indicator.

15. In combination, a pulse generator at a first point operable to produce pulse transmissions comprising one or more time spaced pulses occurring in any of a plurality of fixed time positions to form a plurality of different pulse code patterns, receiving means at a second point for receiving said pulse transmissions, and a coder circuit in said receiving means responsive to the number and time position of said pulses to generate a reply signal having a frequency dependent upon the pattern of said pulse transmissions, a reply signal receiver at said first point, a second coder circuit at said first point coupled to said reply signal receiver and responsive to the code pattern transmitted by said pulse generator to render said reply signal receiver sensitive to receive the reply signal.

16. In combination, a pulse generator at a first point operable to produce pulse transmissions comprising one or more time spaced pulses occurring in any of a plurality of fixed time positions to form a plurality of different pulse code patterns, receiving means at a second point for receiving said pulse transmissions, and a coder circuit in said receiving means responsive to the number and time position of said pulses to generate a reply signal having a frequency dependent upon the pattern of said pulse transmissions, a reply signal receiver at said first point, a second coder circuit at said first point coupled to said reply signal receiver and responsive to the code pattern transmitted by said pulse generator to render said reply signal receiver sensitive to receive the reply signal, and utilization means coupled to the output of said reply signal receiver for utilizing the output derived therefrom.

17. In combination, a pulse generator located at a first point and operable to produce pulse transmissions comprising one or more time spaced pulses occurring in any of a plurality of fixed time positions to form a plurality of different code patterns, a receiving system located at a second point for receiving said pulse transmissions, a coder circuit in said receiving system operative responsive to the number and time position of said pulses to generate a coded reply signal having signal characteristics depending upon the pattern of said pulse transmissions, a reply signal receiver at said first point, a second coder circuit at said first point coupled to said reply signal receiver and responsive to the code pattern transmitted by said pulse generator to render said reply signal receiver sensitive to receive the reply signal, and means for randomly varying the reply code for any given received transmitted code pattern and for synchronously varying the reply receiver signal sensitivity characteristics.

18. In combination, a pulse radar locator system having a pulse transmitter, a rotatable directional antenna, echo pulse receiving means, and a viewing apparatus, an interrogation pulse generator synchronized with said pulse transmitter and operable to produce pulse transmissions comprising one or more time spaced pulses occurring in any of a plurality of fixed time positions to form a plurality of different interrogation pulse patterns, a rotatable directional interrogation transmission antenna, means for synchronizing the rotation of said antennas, a first coder circuit coupled to said interrogation generator for generating a voltage dependent upon the interrogation pattern transmitted, a remote transponder, a receiver for receiving pulses generated by said transponder, a first time delay circuit having a time delay dependent upon the voltage generated in said first coder circuit and coupled to said receiver and said coder circuit, means coupled to said first time delay circuit for introducing the output from said first time delay circuit into the viewing apparatus of said radar locator system, said transponder comprising a receiver tuned to the interrogation transmitter, a second coder circuit identical to the first coder circuit and coupled to said last receiver for generating a voltage dependent upon the interrogation code received, a second time delay circuit having a time delay complementary to that of said first time delay circuit and coupled to said second coder circuit, a generator coupled to said second coder circuit and triggered thereby, and a transponder transmitter coupled to said last named generator for transmitting the pulses generated therein.