Method and system for digital spur cancellation

• US 20060269004A1
• Filed: 11/22/2005
• Published: 11/30/2006
• Est. Priority Date: 05/26/2005
• Status: Active Grant

• Current Assignee: NXP USA, Inc. (NXP Semiconductors NV)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Marholey, Bojko, Kim, Hea Joung, Ibrahim, Brima
• Granted Patent: US 8,116,401 B2
• Time in Patent Office: Days
• US Class Current: 375/260
• CPC Class Codes: H04L 25/03159 operating in the frequency domain H04L25/03165, H04L25/03178 take precedence
• CPC Class Codes: H04L 27/14 Demodulator circuits; Receiver circuits
• CPC Class Codes: H04L 27/34 Amplitude- and phase-modulated carrier systems, e.g. quadrature-amplitude modulated carrier systems
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A method and system for digital spur cancellation may include removing a spur in a left channel minus right channel (L−R) baseband signal generated from a FM signal. The L−R baseband signal may be generated by demodulating a sub-carrier, for example, by using CORDIC algorithm, in a signal demodulated from the FM signal. An orthogonal signal may also be generated by demodulating a sub-carrier, for example, by using CORDIC algorithm, in a signal demodulated from the FM signal. The phase of the orthogonal signal may be further adjusted to introduce a substantially −90° phase shift to spurs at a specific frequency. Accordingly, the spurs in the L−R baseband signal may be cancelled when the first L−R baseband signal is combined with the phase adjusted orthogonal signal.

Claims

1. A method for providing wireless communication, the method comprising:

removing a spur in a first baseband signal generated from a FM signal, comprising;

generating an orthogonal signal when said first baseband signal is generated; and

adjusting a phase of said generated orthogonal signal so that said spur in said first baseband signal is cancelled when said baseband signal is combined with said phase adjusted orthogonal signal.

2. The method according to claim 1, further comprising generating said first baseband signal by demodulating a sub-carrier.

3. The method according to claim 1, further comprising generating said first baseband signal by using CORDIC algorithm to demodulate a sub-carrier.

4. The method according to claim 1, further comprising generating said orthogonal signal using CORDIC algorithm to demodulate a sub-carrier.

5. The method according to claim 1, further comprising delaying said orthogonal signal to said phase adjust said spur by substantially −

90 degrees, whereby said phase adjusted spur is substantially 180 degrees out of phase with respect to spur in said first baseband signal.

6. The method according to claim 1, further comprising using Hilbert transform to said phase adjust at least one said spur by substantially −

90 degrees, whereby said phase adjusted said at least one spur is substantially 180 degrees out of phase with respect to a corresponding spur in said first baseband signal.

7. The method according to claim 1, further comprising delaying said orthogonal signal by using a shift register.

8. The method according to claim 1, further comprising generating a second baseband signal to combine with said combined baseband signal.

9. A machine-readable storage having stored thereon, a computer program having at least one code section for providing wireless communication, the at least one code section being executable by a machine for causing the machine to perform steps comprising:

removing a spur in a first baseband signal generated from a FM signal, comprising;

generating an orthogonal signal when said first baseband signal is generated; and

adjusting a phase of said generated orthogonal signal so that said spur in said first baseband signal is cancelled when said baseband signal is combined with said phase adjusted orthogonal signal.

10. The machine-readable storage according to claim 9, further comprising code for generating said first baseband signal by demodulating a sub-carrier.

11. The machine-readable storage according to claim 9, further comprising code for generating said first baseband signal by using CORDIC algorithm to demodulate a sub-carrier.

12. The machine-readable storage according to claim 9, further comprising code for generating said orthogonal signal by using CORDIC algorithm to demodulate a sub-carrier.

13. The machine-readable storage according to claim 9, further comprising code for delaying said orthogonal signal to said phase adjust said spur by substantially −

90 degrees, whereby said phase adjusted spur is substantially 180 degrees out of phase with respect to spur in said first baseband signal.

14. The machine-readable storage according to claim 9, further comprising code for using Hilbert transform to said phase adjust at least one said spur by substantially −

90 degrees, whereby said phase adjusted said at least one spur is substantially 180 degrees out of phase with respect to a corresponding spur in said first baseband signal.

15. The machine-readable storage according to claim 9, further comprising code for generating said second baseband carrier by using CORDIC algorithm to demodulate a sub-carrier.

16. The machine-readable storage according to claim 9, further comprising code for generating a second baseband signal to combine with said combined baseband signal.

17. A system for providing wireless communication, the system comprising:

circuitry that enables removal of a spur in a first baseband signal generated from a FM signal, comprising;

a baseband generation circuitry that enables generation of an orthogonal signal when said first baseband signal is generated; and

a delay circuitry that enables adjustment of a phase of said generated orthogonal signal so that combining said first baseband signal with said phase adjusted orthogonal signal may result in a combined baseband signal in which said spur is cancelled.

18. The system according to claim 17, wherein a baseband generation circuitry enables generation of said first baseband signal by demodulating a sub-carrier.

19. The system according to claim 17, wherein said baseband generation circuitry enables generation of said first baseband signal by implementing CORDIC algorithm to demodulate a sub-carrier.

20. The system according to claim 17, wherein said baseband generation circuitry enables generation of said orthogonal signal by implementing CORDIC algorithm to demodulate a sub-carrier.

21. The system according to claim 17, wherein said delay circuitry delays said orthogonal signal to said phase adjust said spur by substantially −

90 degrees, whereby said phase adjusted spur is substantially 180 degrees out of phase with respect to spur in said first baseband signal.

22. The system according to claim 17, further comprising circuitry that enables use of Hilbert transform to said phase adjust at least one said spur by substantially −

90 degrees, whereby said phase adjusted said at least one spur is substantially 180 degrees out of phase with respect to a corresponding spur in said first baseband signal.

23. The system according to claim 17, wherein said delay circuitry comprises a shift register to delay said orthogonal signal.

24. The system according to claim 17, further comprising another baseband circuitry that enables generation of a second baseband signal to combine with said combined baseband signal.