Integrated circuit having frequency dependent noise avoidance

• US 8,473,771 B2
• Filed: 10/25/2012
• Issued: 06/25/2013
• Est. Priority Date: 07/26/2006
• Status: Expired due to Fees

• Current Assignee: Avago Technologies General IP PTE Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Rofougaran, Ahmadreza
• Primary Examiner(s): Stoynov, Stefan
• Application Number:
  US13/660,772
• Publication Number:
  US 20130064334A1
• Time in Patent Office: 243 Days
• Field of Search: 713/500, 713/600, 326/93, 327/100, 331/1.R, 331/46, 375/316, 375/354, 455/130
• US Class Current: 713/500
• CPC Class Codes: H04B 15/06 by local oscillators of receivers

Abstract

A clock source generates a first clock signal for clocking a first clocked module and a rate adapting module produces an operation dependent clock signal from the first clock signal for clocking a second clocked module that is rate dependent. The first clock signal has a rate such that frequency dependent noise components associated with the first clock signal are outside a given frequency range that causes adverse performance in the first clocked module.

Claims

1. An apparatus, comprising:

a clock source that generates a first clock signal for clocking a first clocked module, the first clock signal having a rate such that frequency dependent noise components associated with the first clock signal are outside a given frequency range that causes adverse performance in a noise susceptible module; and

a rate adapting module that produces an operation dependent clock signal from the first clock signal for clocking a second clocked module that is rate dependent;

wherein the rate adapting module further functions to;

establish an adjustment factor based on the rate dependency of the second clocked module and the first clock signal; and

adjust the rate of the first clock signal based on the adjustment factor to produce the operation dependent clock signal.

2. The apparatus of claim 1, wherein the first clocked module causes the frequency dependent noise components.

3. The apparatus of claim 2, further comprising:

a filter coupled between the second clocked module and the first clocked module, the filter being clocked based on the operation dependent clock signal.

4. The apparatus of claim 2, wherein the noise susceptible module is a low noise amplifier, the second clocked module is a baseband processing module and the first clocked module is an analog to digital conversion (ADC) module;

and wherein a digital portion of the ADC module is clocked based on the first clock signal.

5. The apparatus of claim 4, wherein the baseband processing module operates to convert an inbound digital signal into inbound data;

and wherein a rate of the operation dependent clock signal is set based on processing specifications of the digital signal.

6. The apparatus of claim 1, wherein the rate adapting module comprises at least one of:

a fractional-N frequency synthesizer;

direct digital frequency synthesizer;

a phase locked loop; and

digital logic circuitry.

7. The apparatus of claim 1, wherein the clock source further functions to:

for an initial rate of the first clock signal, determine whether the frequency dependent noise components are within the given frequency range; and

when the frequency dependent noise components are within the given frequency range, adjust the rate of the first clock signal by calculation such that the frequency dependent noise components associated with the first clock signal are outside the given frequency range.

8. The apparatus of claim 1, wherein the clock source further functions to:

determine whether the frequency dependent noise components are within the given frequency range; and

when the frequency dependent noise components are within the given frequency range, incrementally adjust a rate of the first clock signal such that the frequency dependent noise components associated with the first clock signal are outside the given frequency range.

9. The apparatus of claim 1, wherein the frequency dependent noise comprises at least one of:

harmonic signal components;

spurs; and

digital noise.

10. A radio frequency device, comprising:

a clock module that generates a first clock signal having a rate such that frequency dependent noise components associated with the first clock signal are outside a given frequency range, the clock module further producing an operation dependent clock signal from the first clock signal;

a low noise amplifier that is susceptible to adverse performance when the frequency dependent noise components are within the given frequency range; and

a baseband processing module having at least one function that is rate dependent and clocked based on the operation dependent clock signal;

wherein the clock module further functions to;

establish an adjustment factor based on the rate dependency of the baseband processing module and the first clock signal; and

adjust the rate of the first clock signal based on the adjustment factor to produce the operation dependent clock signal.

11. The radio frequency device of claim 10, wherein the baseband processing module operates to convert an inbound digital signal into inbound data;

and wherein a rate of the operation dependent clock signal is set based on processing specifications of the digital signal.

12. The radio frequency device of claim 10, further comprising:

an analog to digital conversion (ADC) module that causes frequency dependent noise, wherein a digital portion of the ADC module is clocked based on the first clock signal.

13. The radio frequency device of claim 12, further comprising:

a filter coupled between the baseband processing module and the ADC conversion module, the filter being clocked based on the operation dependent clock signal.

14. The radio frequency device of claim 10, wherein the clock module further functions to:

for an initial rate of the first clock signal, determine whether the frequency dependent noise components are within the given frequency range; and

when the frequency dependent noise components are within the given frequency range, adjust the rate of the first clock signal by calculation such that the frequency dependent noise components associated with the first clock signal are outside the given frequency range.

15. The radio frequency device of claim 10, wherein the clock module further functions to:

determine whether the frequency dependent noise components are within the given frequency range; and

when the frequency dependent noise components are within the given frequency range, incrementally adjust a rate of the first clock signal such that the frequency dependent noise components associated with the first clock signal are outside the given frequency range.

16. The radio frequency device of claim 10, wherein the clock module comprises at least one of:

a fractional-N frequency synthesizer;

direct digital frequency synthesizer;

a phase locked loop; and

digital logic circuitry.

17. The radio frequency device of claim 10, wherein the frequency dependent noise comprises at least one of:

harmonic signal components;

spurs; and

digital noise.

18. A method for clocking an apparatus, comprising:

generating a first clock signal for clocking a first clocked module, the first clock signal having a rate such that frequency dependent noise components associated with the first clock signal are outside a given frequency range that causes adverse performance in a noise susceptible module; and

producing an operation dependent clock signal from the first clock signal for clocking a second clocked module that is rate dependent;

wherein producing the operation dependent clock signal further includes;

establishing an adjustment factor based on the rate dependency of the second clocked module and the first clock signal; and

adjusting the rate of the first clock signal based on the adjustment factor to produce the operation dependent clock signal.

19. The method of claim 18, wherein generating the first clock signal further comprises:

determining whether the frequency dependent noise components are within the given frequency range; and

when the frequency dependent noise components are within the given frequency range, adjusting the rate of the first clock signal such that the frequency dependent noise components associated with the first clock signal are outside the given frequency range.

20. The method of claim 18, wherein generating the first clock signal further comprises:

determining whether the frequency dependent noise components are within the given frequency range; and

when the frequency dependent noise components are within the given frequency range, incrementally adjusting a rate of the first clock signal such that the frequency dependent noise components associated with the first clock signal are outside the given frequency range.