MULTIPLE RECEIVER SELECTION SYSTEM

• US 3,860,872 A
• Filed: 02/05/1973
• Issued: 01/14/1975
• Est. Priority Date: 02/05/1970
• Status: Expired due to Term

• Current Assignee: Anthony Keith Sharpe, John Bernard Richardson
• Original Assignee: Anthony Keith Sharpe, John Bernard Richardson
• Inventors: Richardson, John Bernard, Sharpe, Anthony Keith
• Primary Examiner(s): Safourek, Benedict V.
• Assistant Examiner(s): Bookbinder, Marc E.
• Application Number:
  US05/329,865
• Time in Patent Office: 708 Days
• Field of Search: 325/301,304-306,52,53,54,56,473,474,302
• US Class Current: 455/135
• CPC Class Codes: H04B 7/0808 comparing all antennas before reception

Abstract

The invention provides apparatus for selecting from a plurality of receiving stations, each station simultaneously receiving radio frequency signals containing identical information, the signal with the best signal-noise ratio. At each receiving station a control signal is generated, the frequency of which is determined by the signal-noise ratio of the radio signal received by that station. These signals are fed from the respective receiving stations to a central control which monitors the incoming control signals and selects the signal with the best signal-noise ratio.

Claims

1. Apparatus for selecting the highest quality signal from a plurality of signals each containing a signal component carrying identical information and an additional signal component related to the quality thereof, comprising input means for separately receiving said signals, scan control means including sequential driving means, first switching means driven by said driving means for scanning the signals from said input means in successive scanning cycles, signal processing means for providing voltages proportional to the additional signal components from said first switching means, selection control means for producing pulses from the highest voltage of said signal processing means during each scanning cycle, and second switching means connected to said input means and controlled by said selection control means for selecting the highest quality signals from said input means during successive scanning cycles in response to the pulses of said selection control means.

2. Apparatus as claimed in claim 1 wherein said selection control means comprises storage means for receiving the voltages from said signal processing means, means to produce pulses in response to highest stored voltage during each scanning cycle, generating means for producing continuous clock pulses, the time interval of each switching sequence being equal to the time interval between clock pulses, said scan control means driving said first switching means in response to clock pulses from said generating means and producing pulses for discharging said storage means in response to said clock pulses and the pulses from said storage means, the time interval between the initiation of the pulses from said storage means and the pulses from said scan control means being equal to the time interval of said scanning cycle, and means to drive said second switching means in response to the pulses of said storage means and said scan control means.

3. Apparatus as claimed in claim 1 wherein said first and second switching means comprises an array of AND gates for receiving driving signals to produce in sequence output pulses having a duration equal to the interval between successive clock pulses, and transistor switching devices for each AND gate, said transistor switching devices being conductive when supplied with an output pulse from said AND gate and being cut off when said output pulse is absent.

4. Apparatus as claiMed in claim 2 wherein said means for driving said second switching means comprises four bistable circuits operating as a register.

5. Apparatus as claimed in claim 1 further comprising means for indicating signals received and the highest quality signal during successive scanning cycles.

6. Apparatus as claimed in claim 1 wherein said signals having the highest quality comprise signals having the highest signal to noise ratio.

7. A communication system in which a plurality of receiving stations simultaneously receive signals containing identical information, comprising at each receiving station means for generating an auxiliary signal having a frequency which is dependent on the signal-to-noise ratio of the signal received at the station and which is outside the frequency band of the information containing signal, means for combining said information containing signal and said auxiliary signal, and means for transmitting respective combined signals;

a central station including first switch means connected to the output of said transmitting means to scan each combined signal, first filter means connected to the output of said first switch means to reject the information containing signal and pass-through each auxiliary signal, selection means connected to the output of said first filter means and including means for storing the auxiliary signals and means for producing pulses corresponding to the stored highest quality auxiliary signal, second switch means connected to the output of said transmitting means and controlled by the selection means to select a combined signal having highest quality auxiliary signal, and second filter means connected to the output of said second switch means and responsive only to the information containing signal of the selected combined signal.

8. A system as claimed in claim 7 in which means are provided to lower the Q factor of the first filter means during time intervals coincident with the transition periods of the first switch means.

9. A system as claimed in claim 7 further including means to lower the Q factor of the first filter means comprising a damping circuit including a normally non-conducting transistor which is rendered conductive during the transition periods of the first switch means.

10. A system as claimed in claim 7, further including frequency discriminating means for converting each auxiliary signal into a D.C. level and in which the selection means includes a storage capacitor which is charged each time that the received D.C. level exceeds the instantaneous charge on the capacitor, and a generator which in response to an increase in the charge on the capacitor gives an output pulse for controlling said second switch means.

11. A system as claimed in claim 10 in which means are provided to discharge the storage capacitor during each scanning cycle, at a time interval determined by the position of the first switch means, immediately prior to reaching the position corresponding to the position of the second switch.