MULTI-ANTENNA RECEIVER IN A RADIO CONTROLLED CLOCK

• US 20130230094A1
• Filed: 02/11/2013
• Published: 09/05/2013
• Est. Priority Date: 03/05/2012
• Status: Active Grant

• Current Assignee: XW LLC
• Original Assignee: XW LLC
• Inventors: Eliezer, Oren E., Robbins, Dennis I., Jung, Thomas
• Granted Patent: US 8,693,582 B2
• Time in Patent Office: Days
• US Class Current: 375/238
• CPC Class Codes: G04R 20/10 Tuning or receiving; Circuits therefor
• CPC Class Codes: G04R 60/10 inside cases
• CPC Class Codes: H01Q 1/273 Adaptation for carrying or wearing by persons or animals
• CPC Class Codes: H01Q 21/29 Combinations of different interacting antenna units for giving a desired directional characteristic H01Q25/00 takes precedence
• CPC Class Codes: H01Q 7/08 Ferrite rod or like elongated core
• CPC Class Codes: H04B 7/0837 using pre-detection combining H04B7/0868 takes precedence
• CPC Class Codes: H04H 40/27 specially adapted for broadcast systems covered by groups H04H20/53 - H04H20/95
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A novel and useful multi-antenna receiver that receives, demodulates and decodes a broadcast signal, whose modulation and encoding of time and timing information allow for reliable and power-efficient operation. The multi-antenna receiver of the present invention is adapted to eliminate or substantially reduce the reception nulls that occur in receivers having a single antenna that is placed in a fixed position. Two or more antennas are employed whereby the receiver generates a combined signal based on a combination of the individual antenna signals or selects one of the antenna signals for input to the receiver based on desired criteria such as signal-to-noise-and-interference-ratio (SNIR). This results in greater robustness of the communication link by reducing or eliminating reception nulls and by rejecting interference through the selection of the antenna for which the signal-to-interference ratio is higher. The invention includes various antenna configurations that are adapted to reuse a single core for multiple antennas or to otherwise reduce size and/or cost.

Claims

1. A radio receiver, comprising:

a plurality of antennas each adapted to receive a broadcast signal and generate an antenna signal therefrom;

antenna signal combining means operative to generate an antenna output signal from said plurality of antenna signals; and

a receiver circuit operative to receive said antenna output signal comprising a pulse width modulation (PWM)/amplitude shift keyed (ASK) time-code broadcast signal.

2. The radio receiver according to claim 1, further comprising a frame extractor operative to extract phase-modulated time information frames from the phase of said received signal.

3. The radio receiver according to claim 1, further comprising a frame extractor operative to extract time-code information frames from the amplitude/pulse-width of said broadcast signal.

4. The radio receiver according to claim 1, wherein said plurality of antennas comprises at least one printed circuit board (PCB) based antenna.

5. The radio receiver according to claim 1, wherein said plurality of antennas comprises dual antennas positioned substantially orthogonal to each other.

6. The radio receiver according to claim 1, wherein said plurality of antennas comprises three antennas positioned substantially orthogonal to each other.

7. The radio receiver according to claim 1, wherein said plurality of antennas comprises a ferrite rod based antenna positioned substantially orthogonal to a printed circuit board (PCB) based antenna.

8. The radio receiver according to claim 1, wherein said plurality of antennas comprises an ‘

L’

shaped ferrite with a winding on each leg thereof.

9. The radio receiver according to claim 1, wherein said plurality of antennas comprises a single hexahedron shaped ferrite core having overlapping orthogonal windings on two dimensions thereof such that the entire mass of said ferrite is used for both orthogonal directions of magnetic flux.

10. The radio receiver according to claim 1, wherein said plurality of antennas comprises a three dimensional ‘

L’

shaped ferrite with a winding on all three legs thereof.

11. The radio receiver according to claim 1, wherein said plurality of antennas comprises a single hexahedron shaped ferrite having overlapping orthogonal windings in each of three dimensions thereof such that the entire mass of said ferrite is used for three orthogonal directions of magnetic flux.

12. The radio receiver according to claim 1, wherein said plurality of antennas comprises at least one air core flat form factor coils.

13. The radio receiver according to claim 1, wherein said plurality of antennas includes an air core antenna that is based on a wire wound around the face of a vertically mounted clock.

14. The radio receiver according to claim 1, wherein said antenna signal-combining means is operative to select one of said antenna signals based on a maximum signal to noise and interference ratio (SNIR) criterion.

15. The radio receiver according to claim 1, wherein said antenna signal-combining means is operative to combine said antenna signals as a function of SNIR conditions experienced in each of the antennas.

16. The radio receiver according to claim 1, wherein said antenna signal-combining means further comprises means for storing an indication of which of said antennas was optimal over a period of time and to select that antenna a majority of the time.

17. The radio receiver according to claim 1, wherein said plurality of antennas share a ferrite core incorporating at least one capacitor embedded therein that functions as part of a resonant circuit.

18. A radio receiver method, said method comprising:

providing a plurality of substantially-orthogonally positioned antennas, each antenna adapted to receive the same broadcast signal and generate an antenna signal therefrom;

generating a combined antenna output signal from said plurality of antenna signals;

receiving said antenna output signal comprising a pulse width modulation (PWM)/amplitude modulated, time-code broadcast signal encoded which may be additionally modulated with time information frames; and

extracting said time-code or said time information frames from said received signal.

19. The method according to claim 18, further comprising selecting one of said antenna signals based on a signal to noise and interference ratio (SNIR) conditions experienced in each of the antennas.

20. The method according to claim 18, further comprising combining said antenna signals as a function of maximum signal to noise and interference ratio (SNIR).

21. The method according to claim 18, further comprising periodically selecting each of said plurality of antennas.

22. The method according to claim 18, further comprising selecting each of said plurality of antennas at predetermined times.

23. A radio receiver, comprising:

a first antenna adapted to receive a broadcast signal;

a second antenna adapted to receive said broadcast signal, said second antenna oriented substantially orthogonal to said first antenna;

a receiver circuit operative to receive a signal from said first antenna and said second antenna comprising a broadcast signal encoded with time information frames; and

a frame extractor operative to extract said time information frames from said received signal.

24. The radio receiver according to claim 23, wherein said first antenna is selected from the group comprising ferrite rod antenna, ferrite core antenna, air core coil antenna, printed inductor based antenna and semiconductor based antenna.

25. The radio receiver according to claim 23, wherein said second antenna is selected from the group comprising ferrite rod antenna, ferrite core antenna, air core coil antenna, printed circuit board (PCB) inductor based antenna and semiconductor based antenna.

26. The radio receiver according to claim 23, wherein said first and second antennas share a single ferrite core having multiple windings thereon wherein none of the windings share a common axis and thus have different null orientations.

27. The radio receiver according to claim 23, wherein said first and second antennas comprise an ‘

L’

shaped ferrite with a winding on each leg of said ‘

L’

28. The radio receiver according to claim 23, further comprising means for selecting the signal generated by said first antenna and said second antenna as a function of maximum signal to noise and interference ratio (SNIR).

29. The radio receiver according to claim 23, further comprising means for generating a combined antenna signal as a linear combination of the signals generated by said first and second antennas.

30. The radio receiver according to claim 26, wherein said first antenna and said second antenna comprise a shared core with resonating capacitors incorporated therein.