System and method for signal limiting

• US 20050054295A1
• Filed: 10/01/2004
• Published: 03/10/2005
• Est. Priority Date: 10/21/1999
• Status: Active Grant

• Current Assignee: Avago Technologies General IP PTE Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Moloudi, Shervin
• Granted Patent: US 8,014,724 B2
• Time in Patent Office: Days
• US Class Current: 455/63.100
• CPC Class Codes: H03B 21/01 by beating unmodulated signals of different frequencies
• CPC Class Codes: H03C 3/0983 containing in the loop a mixer other than for phase detection
• CPC Class Codes: H03H 11/1291 Current or voltage controlled filters
• CPC Class Codes: H03H 2011/0494 Complex filters
• CPC Class Codes: H03H 21/0001 Analogue adaptive filters
• CPC Class Codes: H03H 21/0012 Digital adaptive filters
• CPC Class Codes: H03J 2200/10 Tuning of a resonator by means of digitally controlled capacitor bank
• CPC Class Codes: H03L 2207/06 Phase locked loops with a controlled oscillator having at least two frequency control terminals
• CPC Class Codes: H03L 7/0891 the up-down pulses controlling source and sink current generators, e.g. a charge pump
• CPC Class Codes: H03L 7/099 concerning mainly the controlled oscillator of the loop
• CPC Class Codes: H03L 7/104 using an additional signal from outside the loop for setting or controlling a parameter in the loop H03L7/107, H03L7/12 take precedence
• CPC Class Codes: H04B 1/40 Circuits
• CPC Class Codes: H04B 17/104 of other parameters, e.g. DC offset, delay or propagation times
• CPC Class Codes: H04B 17/14 of the whole transmission and reception path, e.g. self-test loop-back
• CPC Class Codes: H04B 17/19 Self-testing arrangements

Abstract

Methods and systems for processing a signal with a corresponding noise profile are disclosed. Aspects of the method may comprise analyzing spectral content of the noise profile. At least one noise harmonic within the signal may be filtered based on said analyzed spectral content. The filtered signal may be limited. The noise profile may comprise a phase noise profile. The signal may comprise at least one of a sinusoidal signal and a noise signal. At least one filter coefficient that is used to filter said at least one noise harmonic may be determined. The filtering may comprise low pass filtering and the limiting may comprise hard-limiting the filtered signal. The signal may be modulated prior to the filtering. The signal may be downconverted prior to the modulating. At least one signal component of the signal may be downconverted.

Claims

1. A method for processing a signal with a corresponding noise profile, the method comprising:

analyzing spectral content of the noise profile;

filtering at least one noise harmonic within the signal based on said analyzed spectral content; and

limiting said filtered signal.

2. The method according to claim 1, wherein the noise profile comprises a phase noise profile.

3. The method according to claim 1, wherein the signal comprises at least one of a sinusoidal signal and a noise signal.

4. The method according to claim 1, further comprising determining at least one filter coefficient that is used to filter said at least one noise harmonic.

5. The method according to claim 1, wherein said filtering comprises low pass filtering.

6. The method according to claim 1, wherein said limiting comprises hard-limiting said filtered signal.

7. The method according to claim 1, further comprising modulating the signal prior to said filtering.

8. The method according to claim 7, further comprising downconverting the signal prior to said modulating.

9. The method according to claim 8, further comprising downconverting at least one signal component of the signal.

10. The method according to claim 9, wherein said at least one signal component of the signal comprises an in-phase signal component and a quadrature signal component.

11. The method according to claim 8, further comprising mixing said downconverted signal with a local oscillator signal.

12. The method according to claim 11, further comprising filtering said mixed signal.

13. The method according to claim 12, wherein said filtering comprises low pass filtering of a sum of a carrier frequency of the signal and a reference frequency of said local oscillator signal.

14. The method according to claim 10, further comprising modulating said in-phase signal component and said quadrature signal component with a modulation frequency.

15. The method according to claim 14, further comprising adding said modulated in-phase signal component and said modulated quadrature signal component to obtain a downconverted modulated signal.

16. The method according to claim 1, further comprising detecting a phase difference between said limited signal and a reference signal.

17. A system for processing a signal with a corresponding noise profile, the system comprising:

a processor that analyzes spectral content of the noise profile;

a filter that filters at least one noise harmonic within the signal based on said analyzed spectral content; and

a limiter that limits said filtered signal.

18. The system according to claim 17, wherein the noise profile comprises a phase noise profile.

19. The system according to claim 17, wherein the signal comprises at least one of a sinusoidal signal and a noise signal.

20. The system according to claim 17, wherein the processor determines at least one filter coefficient that is used to filter said at least one noise harmonic.

21. The system according to claim 17, wherein said filter comprises a low-pass filter.

22. The system according to claim 17, wherein said limiter comprises a hard-limiter that limits said filtered signal.

23. The system according to claim 17, further comprising a modulator that modulates the signal prior to said filtering.

24. The system according to claim 23, further comprising a downconverter that downconverts the signal prior to said modulating.

25. The system according to claim 24, wherein said downconverter downconverts at least one signal component of the signal.

26. The system according to claim 25, wherein said at least one signal component of the signal comprises an in-phase signal component and a quadrature signal component.

27. The system according to claim 24, further comprising a mixer that mixes said downconverted signal with a local oscillator signal.

28. The system according to claim 27, further comprising a filter that filters said mixed signal.

29. The system according to claim 28, wherein said filter comprises a low pass filter that filters a sum of a carrier frequency of the signal and a reference frequency of said local oscillator signal.

30. The system according to claim 26, further comprising a modulation mixer that modulates said in-phase signal component and said quadrature signal component with a modulation frequency.

31. The system according to claim 30, further comprising an adder that adds said modulated in-phase signal component and said modulated quadrature signal component to obtain a downconverted modulated signal.

32. The system according to claim 17, further comprising a phase detector that detects a phase difference between said limited signal and a reference signal.