SINGLE ANTENNA SIGNAL RETRANSMISSION DEVICE

• US 3,685,050 A
• Filed: 04/13/1970
• Issued: 08/15/1972
• Est. Priority Date: 04/13/1970
• Status: Expired due to Term

• Current Assignee: Victor F. Cartwright
• Original Assignee: Victor F. Cartwright
• Inventors: Cartwright, Victor F.
• Primary Examiner(s): Hubler, Malcolm F.
• Application Number:
  US05/027,538
• Time in Patent Office: 855 Days
• Field of Search: 1s/902 343/6.8R,6.8LC,18B,18C,18D,18E
• US Class Current: 342/6
• CPC Class Codes: G01S 13/767 Responders; Transponders teaching or practice apparatus for gun-aiming or gun-laying using reflecting targets or active targets F41G3/26

Abstract

A device for receiving a signal via an antenna and for retransmitting via the same antenna an augmented signal of identical frequency and coherent phase. A circulator connected to the antenna directs the received signal to a diode switch and thence to a broadband RF amplifier. The switch periodically, alternately isolates and passes the received signal to the amplifier in response to a square wave control signal having a frequency considerably lower than that of the received signal. The sampled, amplified signal is delayed by a time duration substantially equal to one-half the period of the control signal, and then supplied via the circulator to the antenna. The device is useful as an augmentation amplifier, and for enhancing radar target reflectivity.

Claims

1. Apparatus for receiving a signal via an antenna, amplifying said signal, and concurrently retransmitting the amplified signal from the same antenna while retaining the relative amplitude, frequency, and phase characteristics of the received signal, said apparatus comprising:

first means operatively coupled to said antenna for periodically sampling and amplifying said received signal;

second means operatively coupled to said first means for delaying said sampled and amplified signal by an amount of time equal to one-half the reciprocal of the sampling rate; and

third means operatively coupled to said second means for coupling to said antenna said delayed, sampled and amplified signal.

2. Apparatus as defined in claim 1 wherein said received signal is a cw or pulsed RF signal.

3. Apparatus as defined in claim 1 wherein said first means samples said received signal at a frequency substantially lower than that of said received signal.

4. Apparatus as defined in claim 1 wherein said first means comprises:

an RF amplifier; and

diode switch means for alternately isolating and passing said received signal to said amplifier.

5. Apparatus as defined in claim 4 wherein said diode switch means provides an isolation substantially greater than the gain of said amplifier.

6. Apparatus as defined in claim 4 wherein said diode switch means is controlled by a square wave signal of frequency fs substantially lower than the frequency of said received signal, and wherein said received signal is passed to said amplifier only when said square wave signal is true.

7. Apparatus as defined in claim 6 wherein said received signal is pulsed, and wherein said sample period is less than the pulse duration of said received signal.

8. Apparatus as defined in claim 4 further comprising a circulator cooperating with said antenna and wherein said second means comprises a delay line inserted between the output of said RF amplifier and said circulator.

9. Apparatus as defined in claim 8 wherein said delay line comprises a coaxial line exhibiting a delay time approximately equal to 1/2 fs where fs is the sampling rate.

10. An RF signal retransmission device comprising:

an antenna, a circulator connected to said antenna, an RF amplifier, switch means for periodically, alternately isolating and passing a received RF signal from said circulator to the input of said RF amplifier, and a delay line connecting the output of said RF amplifier to said circulator, and providing a delay related to the periodicity of said switch means.

11. A retransmission device as defined in claim 10 wherein said switch means comprises a diode switch controlled by a periodic control signal of frequency fs, the frequency of said received signal being at least 50fs.

12. A retransmission device as defined in claim 11 wherein said periodic control signal comprises a square wave, said RF signal being passed to said amplifier when said square wave is true, and wherein the delay time of said delay line is substantially equal to the time that said square wave is true during each period thereof.

13. A retransmission device as defined in claim 10 wherein said RF amplifier is broadband and provides an output signal of the same frequency and in phase coherence with the input thereto, said retransmission device thereby transmitting from said antenna an augmented signal identical in frequency and coherent in phase with the signal received by the same antenna.

14. A retransmission device as defined in claim 13 further comprising means for pulse code modulating the signal being amplified by said RF amplifier.