IP Library Granted Patent US 7,409,020
Granted Patent B1
US 7,409,020 · App. 10/732,532 · Granted Aug 5, 2008

Technique for filter-enhanced clock synchronization

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Quick Facts
Patent No.
US 7,409,020
App. No.
10/732,532
Granted
Aug 5, 2008
Kind
B1
Abstract

A technique for filter-enhanced clock synchronization is disclosed. In one particular exemplary embodiment, the technique may be realized by/as a method for filter-enhanced clock synchronization. The method comprises subjecting a clock error signal to a first exponentially weighted moving average (EWMA) filter to generate a first output signal, where the first EWMA filter comprises a first gain element. And the method further comprises subjecting the first output signal to a second EWMA filter to generate a second output signal, where the second EWMA filter comprises a second gain element and the second EWMA filter is coupled with a feedback loop having a delay element and a summing junction.

Claims (25)

1. A method for filter-enhanced clock synchronization, the method comprising:

subjecting a clock error signal to a first exponentially weighted moving average (EWMA) filter to generate a first output signal, where the first EWMA filter comprises a first gain element; and

subjecting the first output signal to a second EWMA filter to generate a second output signal, where the second EWMA filter comprises a second gain element;

wherein the first EWMA filter is coupled with a first feedback loop having a first delay element and a first summing junction;

wherein the second EWMA filter is coupled to a second feedback loop having a second delay element and a second summing junction.

2. The method according to claim 1 , where at least one of the first gain element and the second gain element is a tunable gain element.

3. The method according to claim 2 , further comprising tuning at least one of the first gain element and the second gain element to achieve a desired response time and performance for the second output signal.

4. The method according to claim 1 , wherein the second feedback loop comprises a third gain element.

5. The method according to claim 4 , where the third gain element is a tunable gain element.

6. The method according to claim 5 , further comprising tuning the third gain element, in addition to the first gain element and the second gain element, to achieve a desired response time and performance for the second output signal.

7. The method according to claim 1 , where the first feedback loop comprises a third gain element.

8. The method according to claim 7 , where the third gain element is a tunable gain element.

9. At least one computer readable medium for storing instructions configured to be readable by at least one processor for instructing the at least one processor to execute a computer process for performing the method as recited in claim 1 .

10. An apparatus for filter-enhanced clock synchronization, the apparatus comprising:

a first exponentially weighted moving average (EWMA) filter to generate a first output signal, where the first EWMA filter comprises a first gain element; and

a second EWMA filter to receive the first output signal and generate a second output signal, where the second EWMA filter comprises a second gain element;

wherein the first EWMA filter is coupled with a first feedback loop having a first delay element and a first summing junction;

wherein the second EWMA filter is coupled to a second feedback loop having a second delay element and a second summing junction.

11. The apparatus according to claim 10 , where at least one of the first gain element and the second gain element is a tunable gain element.

12. The apparatus according to claim 11 , where at least one of the first gain element and the second gain element is tuned to achieve a desired response time and performance for the second output signal.

13. The apparatus according to claim 10 , wherein the second feedback loop comprises a third gain element.

14. The apparatus according to claim 13 , where the third gain element is a tunable gain element.

15. The apparatus according to claim 14 , where the third gain element is tuned, in addition to the first gain element and the second gain element, to achieve a desired response time and performance for the second output signal.

16. The apparatus according to claim 10 , where the first feedback loop comprises a third gain element.

17. The apparatus according to claim 16 , where the third gain element is a tunable gain element.

Assignments (6)
RELEASE (REEL 038041 / FRAME 0001) Recorded Jan 2, 2018
From: JPMORGAN CHASE BANK, N.A.
To: RPX CORPORATION; RPX CLEARINGHOUSE LLC
Reel/Frame 044970/0030 →
SECURITY AGREEMENT Recorded Mar 9, 2016
From: RPX CORPORATION; RPX CLEARINGHOUSE LLC
To: JPMORGAN CHASE BANK, N.A., AS COLLATERAL AGENT
Reel/Frame 038041/0001 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Feb 9, 2015
From: ROCKSTAR CONSORTIUM US LP; ROCKSTAR CONSORTIUM LLC; BOCKSTAR TECHNOLOGIES LLC; CONSTELLATION TECHNOLOGIES LLC; MOBILESTAR TECHNOLOGIES LLC; NETSTAR TECHNOLOGIES LLC
To: RPX CLEARINGHOUSE LLC
Reel/Frame 034924/0779 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Mar 11, 2014
From: ROCKSTAR BIDCO, LP
To: ROCKSTAR CONSORTIUM US LP
Reel/Frame 032425/0867 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Oct 28, 2011
From: NORTEL NETWORKS LIMITED
To: ROCKSTAR BIDCO, LP
Reel/Frame 027164/0356 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Dec 11, 2003
From: WYRZYKOWSKA, ANETA; SOH, KAH MING; AWEYA, JAMES; MONTUNO, DELFIN; OUELLETTE, MICHEL
To: NORTEL NETWORKS LIMITED
Reel/Frame 014792/0760 →