Adaptive antenna system employing FM receiver

• US 4,220,954 A
• Filed: 12/20/1977
• Issued: 09/02/1980
• Est. Priority Date: 12/20/1977
• Status: Expired due to Term

• Current Assignee: Marchand Electronic Laboratories Incorporated
• Original Assignee: Marchand Electronic Laboratories Incorporated
• Inventors: Marchand, Nathan
• Primary Examiner(s): Blum, Theodore M.
• Application Number:
  US05/862,373
• Time in Patent Office: 987 Days
• Field of Search: 343/113 R, 343/120
• US Class Current: 342/433
• CPC Class Codes: G01S 3/46 using antennas spaced apart and measuring phase or time difference between signals therefrom, i.e. path-difference systems
• CPC Class Codes: H01Q 3/2623 composed of two antennas

Abstract

In an adaptive antenna system, the output of the discriminator of an FM receiver is synchronously rectified, in synchronism with commutation of the input thereof between a pair of antennas, to provide an output signal. When the inputs of the receiver are coupled directly to the antennas, the system may be employed in a homing mode. The output of the rectifier may alternatively be employed to control amplitude and/or phase controls connected between a pair of antennas and the input circuits of the receiver, for the use of the receiver in an adaptive system. For control of amplitude, a quadrature hybrid may be connected between the antennas and the input circuit of the receiver, in order to balance the amplitude of the received signals. In a further arrangement, the inputs to the receiver may be coupled to a sum-difference hybrid coupled to the antennas by way of phase and amplitude control devices, the inputs to the receiver being controlled on a time sharing basis to enable use of the same receiver for controlling the adaptation of the antennas and for receiving intelligent signals. The control functions of this system may be effected in accordance with a programmed control circuit.

Claims

1. In a system responsive to the direction of propagation of a radiation of radio waves bearing a pair of spaced apart antennas are provided for receiving said radiation;

the improvement comprising frequency modulation discriminator means, means alternately coupling signals received by said antennas to said discriminator means, an output circuit, synchronous rectifying means coupling the output of said discriminator means to said output circuit, said synchronous rectifying means being synchronized with said antenna coupling means, a sum-difference hybrid, means applying the signals received by said antenna to said sum-difference hybrid, including phase shift means connecting at least one of said antennas to said sum-difference hybrid, means controlling the phase shift of said phase shifting means with the signals of said output circuit, whereby the sum and difference outputs of said hybrid are responsive to said direction of propagation, and further comprising phase shifter means coupling the output of said discriminator means to said synchronous rectifying means.

2. In a system responsive to the direction of propagation of a radiation of radio waves wherein a pair of spaced apart antennas are provided for receiving said radiation;

the improvement comprising frequency modulation discriminator means, means alternately coupling signals received by said antennas to said discriminator means, an output circuit, synchronous rectifying means coupling the output of said discriminator means to said output circuit, said synchronous rectifying means being synchronized with said antenna coupling means, a sum-difference hybrid, means applying the signals received by said antenna to said sum-difference hybrid, including phase shift means connecting at least one of said antennas to said sum-difference hybrid, means controlling the phase shift of said phase shifting means with the signals of said output circuit, whereby the sum and difference outputs of said hybrid are responsive to said direction of propagation, means for converting signal amplitude variations to phase difference variations and connected to apply the signals received by said antennas to said antenna coupling means, variable attenuator means coupling the signals received by at least one of said antennas to said converting means, and means applying the signals of said output circuit means to control the attenuation of said attenuating means, said converting means comprising a quadrature hybrid.

3. In an adaptive array system having first and second input terminals for connection to separate spaced apart antennas;

the improvement comprising first and second input circuits, frequency discriminator means, commutation means selectively coupling said first and second input circuits to said discriminator means, synchronous rectifying means synchronized with said commutation means and coupled to the output of said discriminator means, variable control means coupled to said input terminals, means for converting amplitude variations to phase variations for coupling said variable signal control means to said input circuits, and means controlling said variable control means with the output of said synchronous rectifying means, said variable control means comprising variable attenuator means, said converting means comprising quadrature hybrid means.

4. In an adaptive array system having first and second input terminals for connection to separate spaced apart antennas;

the improvement comprising first and second input circuits, frequency discriminator means, commutation means selectively coupling said first and second input circuits to said discriminator means, synchronous rectifying means synchronized with said commutation means and coupled to the output of said discriminator means, variable control means coupled to said input terminals, means for converting amplitude variations to phase variations for coupling said variable control means to said input circuits, and means controlling said variable control means with the output of said synchronous rectifying means, said control means comprising separate phase shifting and attenuation control means, time sharing switching means coupled to apply input signals to said first and second input circuits, first means coupling the output of said phase shifting means to said time sharing means, and second means coupling the output of said attenuator means to said time sharing means, said second means comprising means for converting amplitude variations to phase variations.

5. The system of claim 4 wherein said phase shifting means are coupled to said input terminals ahead of said attenuator means.

6. The system of claim 4 wherein attenuator means are connected to said input terminals ahead of said phase shifting means.

7. In an adaptive array system having first and second input terminals for connection to separate spaced apart antennas;

the improvement comprising first and second input circuits, frequency discriminator means, commutation means selectively coupling said first and second input circuits to said discriminator means, synchronous rectifying means synchronized with said commutation means and coupled to the output of said discriminator means, sum-difference hybrid means having its sum and difference outputs coupled to said first and second input circuits respectively, means including control means coupling said first and second input terminals to the input of said hybrid, means controlling said control means with the output of said synchronous rectifying means, and comprising time sharing means for selectively coupling the output of said control means and the outputs of said hybrid to said first and second input circuits.

8. In an adaptive array system having first and second input for connection to separate spaced apart antennas;

the improvement comprising first and second input circuits, frequency discriminator means, commutation means selectively coupling said first and second input circuits to said discriminator means, synchronous rectifying means synchronized with said commutation means and coupled to the output of said discriminator means, sum-difference hybrid means having its sum and difference outputs coupled to said first and second input circuits respectively, means including control means coupling said first and second input terminals to the input of said hybrid, means controlling said control means with the output of said synchronous rectifying means, said control means comprising variable attenuation means and variable phase shifting means, and further comprising a phase shifter coupled between one of the outputs of said hybrid and the respective input circuit, compensator means selectively connectable to bypass said phase shifter, and further comprising additional compensator means coupling the other output of said hybrid to the respective input dircuit, and time sharing control means for enabling separate control of said attenuation and phase shifting means.

9. In an adaptive antenna array system having first and second input terminals for connection to separate spaced apart antennas;

the improvement comprising first and second input circuits, frequency discriminator means, commutation means selectively coupling said first and second input circuits to said discriminator means, synchronous rectifying means synchronized with said commutation means and coupled to the output of said discriminator means, sum-difference hybrid means, variable phase shifting means and variable attenuation means coupling said first and second input terminals to the inputs of said sum-difference hybrid, fixed phase shift means connected to couple one output of said hybrid to said first input circuits, means coupling the other output of said hybrid to said second input circuit, first commutation means connected to control the insertion of said phase shifter, second and third commutation means connected to selectively control said variable phase shifting means variable attenuator means with the output of said rectifying means, and programmed circuit means for selectively controlling said first, second and third commutation means.

10. The system of claim 9 wherein said discriminator means comprises FM receiver means including signal identification means, said programmed circuit means being responsive to said signal identification means.

11. The system of claim 10 further comprising a signal output circuit, fourth commutation means coupling the output of said rectifying means, said programmed means comprising means for controlling said fourth commutation means.

12. The system of claim 11 further comprising fifth and sixth commutation means for selectively opening the inputs to said first and second inputs, said programmed circuit comprising means for controlling said fifth and sixth commutation means.

13. The system of claim 12 further comprising seventh commutation means controlled by said programmed circuit for selectively interconnecting said first and second input circuits.