Multi-antenna receiver in a radio controlled clock

• US 8,693,582 B2
• Filed: 02/11/2013
• Issued: 04/08/2014
• Est. Priority Date: 03/05/2012
• Status: Expired due to Fees

• Current Assignee: XW LLC
• Original Assignee: XW LLC
• Inventors: Eliezer, Oren E., Robbins, Dennis I., Jung, Thomas
• Primary Examiner(s): Ha, Dac
• Assistant Examiner(s): TIEU, JANICE N
• Application Number:
  US13/764,049
• Publication Number:
  US 20130230094A1
• Time in Patent Office: 421 Days
• Field of Search: 375/238, 132/38, 133/16, 133/20, 133/40, 343787-788, 455/7, 455/13.3, 455/19, 455/25, 455 631- 634, 455 82- 83, 455/562.1, 455/575.7, 455/107, 455/121, 455/274, 370/334, 370/339
• US Class Current: 375/320
• 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 for use in a radio controlled clock (RCC), comprising:

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

an antenna multiplexor operative to generate an antenna output signal from said plurality of antenna signals;

a receiver circuit operative to receive said antenna output signal comprising a pulse width modulation (PWM)/amplitude modulation time-code broadcast signal; and

wherein at least a first antenna is selected from the group consisting of a ferrite rod antenna, ferrite core antenna, air core coil antenna, printed inductor based antenna and semiconductor based antenna.

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 at least a second antenna comprises a printed circuit board (PCB) based antenna.

5. The radio receiver according to claim 1, wherein at least said first antenna and at least a second antenna are positioned substantially orthogonal to each other.

6. The radio receiver according to claim 1, wherein at least said first antenna and at least a second antenna and third antennas are positioned substantially orthogonal to each other.

7. The radio receiver according to claim 1, wherein at least said first antenna is positioned substantially orthogonal to at least a printed circuit board (PCB) based second antenna.

8. The radio receiver according to claim 1, wherein at least said first antenna and at least a second antenna comprise an ‘

L’

shaped ferrite with a winding on each leg thereof.

9. The radio receiver according to claim 1, wherein at least said first antenna and at least a second antenna comprise 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 at least said first antenna and at least a second and third antennas comprise a three dimensional ‘

L’

shaped ferrite with a winding on all three legs thereof.

11. The radio receiver according to claim 1, wherein at least said first antenna and at least a second and third antennas comprise 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 at least a second antenna comprises an air core flat form factor coils.

13. The radio receiver according to claim 1, wherein at least a second antenna comprises an air core antenna incorporating a wire wound around the face of a vertically mounted clock.

14. The radio receiver according to claim 1, wherein said antenna multiplexor 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 multiplexor 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 multiplexor further comprises a controller operative to store 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 at least said first antenna and at least a second antenna share a ferrite core incorporating at least one capacitor embedded therein that functions as part of a resonant circuit.

18. A radio receiver method for use in a radio controlled clock (RCC), said method comprising:

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

generating an 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 with time information frames;

extracting said time-code or said time information frames from said received signal; and

wherein at least a first antenna is selected from the group consisting of a ferrite rod antenna, ferrite core antenna, air core coil antenna, printed inductor based antenna and semiconductor based antenna.

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 for use in a radio controlled clock (RCC), 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;

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

wherein said first antenna is selected from the group consisting of a ferrite rod antenna, ferrite core antenna, air core coil antenna, printed inductor based antenna and semiconductor based antenna.

24. The radio receiver according to claim 23, wherein said receiver circuit further comprises a controller operative to store an indication of which of said first and second antennas was optimal over a period of time and to select that antenna a majority of the time.

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 26, wherein said first antenna and said second antenna comprise a shared core with resonating capacitors incorporated therein.

28. 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’

.

29. The radio receiver according to claim 23, further comprising a controller operative to select the signal generated by said first antenna and said second antenna as a function of maximum signal to noise and interference ratio (SNIR).

30. The radio receiver according to claim 23, further comprising a controller operative to generate a combined antenna signal as a linear combination of the signals generated by said first and second antennas.

31. A radio receiver for use in a radio controlled clock (RCC), comprising:

a first antenna input adapted to receive a broadcast signal encoded with time information from a first antenna coupled thereto;

a second antenna input adapted to receive said broadcast signal from a second antenna coupled thereto;

a multiplexor coupled to and operative to select either of said first antenna input or said second antenna input in accordance with a control signal;

a receiver circuit operative to receive the output of said multiplexor and to generate an output signal therefrom;

a decoder coupled to said receiver and operative to extract said time information from said output signal;

a controller operative configure said multiplexor to couple said first antenna input to said receiver circuit and to toggle to the second antenna input in the event reception fails using the first antenna input; and

wherein said first antenna is selected from the group consisting of a ferrite rod antenna, ferrite core antenna, air core coil antenna, printed inductor based antenna and semiconductor based antenna.

32. The radio receiver according to claim 31, wherein said controller never switches said multiplexor to said second antenna input if reception through said first antenna is repeatedly successful.

33. The radio receiver according to claim 31, wherein said controller never switches said multiplexor to said second antenna input as long as reception through said first antenna is repeatedly successful.

34. The radio receiver according to claim 33, wherein said receiver never determines which antenna experiences superior reception.

35. The radio receiver according to claim 31, wherein said controller is operative to select an antenna arbitrarily at startup.

36. The radio receiver according to claim 31, wherein said controller is operative to select the antenna associated with the previous successful reception and only toggles to the other antenna in response to a reception failure.