US5406587A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Error tracking loop
Assignee: Zenith Electronics LLC
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Filing: 1993-02-08
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Granted: 1995-04-11
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Expires: 2013-02-08
Abstract
Abstract A circuit for error correcting a received complex data signal comprises a synchronous detector for recovering an in-phase data component from the received signal and a Hilbert transform filter for estimating the related quadrature component from the recovered in-phase data component, the recovered in-phase data component including a periodically recurring reference signal. A decision feedback loop is periodically operable in response to the reference signal for initially error correcting a selected characteristic of the received signal at a first relatively rapid rate and for subsequently error correcting the selected characteristic at a rate which is less than the first rate and which is dependent upon the estimated S/N ratio of the received signal. In one embodiment, phase errors are corrected at a rate which is also directly related to the value of the estimated quadrature component. In another embodiment, amplitude errors, e.g. gain and offset, are corrected at a rate which is inversely related to the value of the estimated quadrature component.
Inventors
- 👤 Thomas P. Horwitz
- 👤 Ronald B. Lee
- 👤 Gopalan Krishnamurthy
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 18:02
CPC Classifications
H; H04; H04L; H04L27/00; H04L27/02
Claims Analysis
Total Claims: 53
Claim 1
Independent Claim
77 words
A phase noise tracking circuit comprising: means for receiving a complex data signal having an in-phase data component and a related quadrature component; means for recovering said in-phase data component from said received signal; means for approximating said quadrature component from said recovered in-phase data component; and means for adjusting the phase of the vector comprising said recovered in-phase data component and said approximated quadrature component to reduce the phase noise characterizing said recovered in-phase data component.
Claim 2
Dependent Claim
77 words
A phase noise tracking circuit comprising: means for receiving a complex data signal having an in-phase data component and a related quadrature component; means for recovering said in-phase data component from said received signal; means for approximating said quadrature component from said recovered in-phase data component; and means for adjusting the phase of the vector comprising said recovered in-phase data component and said approximated quadrature component to reduce the phase noise characterizing said recovered in-phase data component.
Claim 3
Dependent Claim
30 words
The circuit of claim 1 wherein said adjusting means comprises means for adjusting the phase of said vector at a rate dependent upon the value of said approximated quadrature component.
Claim 4
Dependent Claim
30 words
The circuit of claim 1 wherein said adjusting means comprises means for adjusting the phase of said vector at a rate dependent upon the S/N ratio of said received signal.
Claim 5
Dependent Claim
40 words
The circuit of claim 1 wherein said adjusting means comprises means for adjusting the phase of said vector at a rate dependent upon the difference between the level of said recovered in-phase data component and the closest valid level thereof.
Claim 6
Dependent Claim
58 words
The circuit of claim 1 wherein said received signal comprises a plurality of successive data fields each including a reference signal which is more reliably recoverable than the remainder of the respective data field and wherein said adjusting means is responsive to said reference signal for adjusting the phase of said vector at a first relatively rapid rate.
Claim 7
Dependent Claim
49 words
The circuit of claim 5 wherein said adjusting means is responsive to said remainders of each of said data fields for adjusting the phase of said vector at a rate which is less than said first rate and which is dependent upon the S/N ratio of said received signal.
Claim 8
Dependent Claim
27 words
The circuit of claim 6 including means responsive to said reference signal for estimating the S/N ratio of said received signal for each of said data fields.
Claim 9
Dependent Claim
27 words
The circuit of claim 7 including means for resetting said adjusting means and said S/N ratio estimating means at the beginning of each of said data fields.
Claim 10
Dependent Claim
56 words
The circuit of claim 1 wherein said adjusting means comprises means for developing an error signal representing the difference between said recovered in-phase data component and the closest valid value thereof, means for accumulating said error signal and means for rotating said vector by an amount and in a direction corresponding to said accumulated error signal.
Claim 11
Dependent Claim
28 words
The circuit of claim 9 wherein said error signal developing means comprises means for developing said error signal in response to the value of said approximated quadrature component.
Claim 12
Dependent Claim
28 words
The circuit of claim 9 wherein said error signal developing means comprises means for developing said error signal in response to the S/N ratio of said received signal.
Claim 13
Dependent Claim
65 words
The circuit of claim 9 wherein said received signal comprises a plurality of successive data fields each including a reference signal which is more reliably recoverable than the remainder of the respective data field and wherein said error signal developing means is responsive to said reference signal for developing said error signal for adjusting the phase of said vector at a first relatively rapid rate.
Claim 14
Dependent Claim
56 words
The circuit of claim 12 wherein said error signal developing means is responsive to said remainders of each of said data fields for developing said error signal for adjusting the phase of said vector at a rate which is less than said first rate and which is dependent upon the S/N ratio of said received signal.
Claim 15
Dependent Claim
27 words
The circuit of claim 13 including means responsive to said reference signal for estimating the S/N ratio of said received signal for each of said data fields.
Claim 16
Dependent Claim
27 words
The circuit of claim 14 including means for resetting said S/N ratio estimating means and said accumulating means at the beginning of each of said data fields.
Claim 17
Dependent Claim
23 words
The circuit of claim 1 wherein said approximating means comprises means for performing an approximate Hilbert transform of said recovered in-phase data component.
Claim 18
Dependent Claim
32 words
The circuit of claim 1 wherein said adjusting means comprises decision feedback means responsive to a selected one of a plurality of tables of valid levels of said recovered in-phase data component.
Claim 19
Dependent Claim
77 words
A circuit for error correcting a selected characteristic of a received signal comprising: means for receiving a complex data signal having an in-phase data component and a related quadrature component; means for recovering said in-phase data component from said received signal and for approximating said quadrature component from said recovered in-phase data component; and means responsive to said recovered in-phase data component and said approximated quadrature component for error correcting said selected characteristic of said received signal.
Claim 20
Dependent Claim
77 words
A circuit for error correcting a selected characteristic of a received signal comprising: means for receiving a complex data signal having an in-phase data component and a related quadrature component; means for recovering said in-phase data component from said received signal and for approximating said quadrature component from said recovered in-phase data component; and means responsive to said recovered in-phase data component and said approximated quadrature component for error correcting said selected characteristic of said received signal.
Claim 21
Dependent Claim
32 words
The circuit of claim 18 wherein said means for error correcting comprises means for adjusting the phase of the complex signal comprising said recovered in-phase data component and said approximated quadrature component.
Claim 22
Dependent Claim
29 words
The circuit of claim 18 wherein said means for approximating comprises means for performing an approximate Hilbert transform on said recovered in-phase data component for deriving said quadrature component.
Claim 23
Dependent Claim
45 words
The circuit of claim 19 wherein said means for error correcting comprises means for adjusting the phase of said complex signal comprising said recovered in-phase data component and said approximated quadrature component at a rate dependent upon the value of said phase adjusted quadrature component.
Claim 24
Dependent Claim
67 words
The circuit of claim 19 wherein said means for error correcting comprises means for developing an error signal representing the difference between said phase adjusted in-phase data component and a plurality of stored values, means for accumulating said error signal and means responsive to said accumulated error signal for adjusting the phase of said complex signal comprising said recovered in-phase data component and said approximated quadrature component.
Claim 25
Dependent Claim
25 words
The circuit of claim 22 wherein said error signal developing means comprises means responsive to said phase adjusted quadrature component for developing said error signal.
Claim 26
Dependent Claim
27 words
The circuit of claim 22 wherein said error signal developing means comprises means responsive to the S/N ratio of said received signal for developing said error signal.
Claim 27
Dependent Claim
147 words
The circuit of claim 22 wherein said received signal comprises a periodically occurring reference signal and including means responsive to said reference signal for estimating the S/N ratio of said received signal and means for resetting said estimating means and said accumulating means at a rate corresponding to the rate of said periodically occurring reference signal, said error signal developing means being responsive to said reference signal for developing said error signal for adjusting the phase of said complex signal comprising said recovered in-phase data component and said approximated quadrature component at a first relatively rapid rate and otherwise responsive to said estimating means for developing said error signal for adjusting the phase of said complex signal comprising said recovered in-phase data component and said approximated quadrature component at a rate which is less than said first rate and which is dependent upon said estimated S/N ratio.
Claim 28
Dependent Claim
102 words
A circuit for correcting errors in a received signal comprising: means for receiving a complex data signal having an in-phase data component and a related quadrature component; means for recovering said in-phase data component from said received signal and a quadrature signal representing said quadrature component; means for adjusting the complex signal comprising said recovered in-phase data component and said quadrature signal for error correcting a selected characteristic thereof; and means responsive to said error corrected complex signal for controlling said adjusting means for correcting said selected characteristic at a rate which is a function of the value of said quadrature signal.
Claim 29
Dependent Claim
102 words
A circuit for correcting errors in a received signal comprising: means for receiving a complex data signal having an in-phase data component and a related quadrature component; means for recovering said in-phase data component from said received signal and a quadrature signal representing said quadrature component; means for adjusting the complex signal comprising said recovered in-phase data component and said quadrature signal for error correcting a selected characteristic thereof; and means responsive to said error corrected complex signal for controlling said adjusting means for correcting said selected characteristic at a rate which is a function of the value of said quadrature signal.
Claim 30
Dependent Claim
19 words
The circuit of claim 26 including means responsive to said recovered in-phase data component for approximating said quadrature signal.
Claim 31
Dependent Claim
14 words
The circuit of claim 27 wherein said approximating means comprises an approximate Hilbert transform.
Claim 32
Dependent Claim
27 words
The circuit of claim 26 wherein said adjusting means comprises means for adjusting the phase of the complex signal comprising said recovered in-phase component and quadrature signal.
Claim 33
Dependent Claim
37 words
The circuit of claim 26 wherein said controlling means comprises means for controlling said adjusting means for error correcting said selected characteristic at a rate which is a direct function of the value of said quadrature signal.
Claim 34
Dependent Claim
21 words
The circuit of claim 26 wherein said adjusting means comprises means for adjusting an amplitude-related characteristic of said received complex signal.
Claim 35
Dependent Claim
27 words
The circuit of claim 31 wherein said controlling means comprises means for controlling said adjusting means as an inverse function of the value of said quadrature signal.
Claim 36
Dependent Claim
20 words
The circuit of claim 32 wherein said adjusting means comprises means for adjusting the gain of said received complex signal.
Claim 37
Dependent Claim
20 words
The circuit of claim 32 wherein said adjusting means comprises means for adjusting the offset of said received complex signal.
Claim 38
Dependent Claim
33 words
The circuit of claim 26 wherein said controlling means comprises means for controlling said adjusting means for error correcting said selected characteristic as a function of the S/N ratio of said received signal.
Claim 39
Dependent Claim
51 words
The circuit of claim 32 wherein said controlling means comprises means for developing an error signal representing the difference between said error corrected in-phase data component and a plurality of stored values, means for accumulating said error signal and means responsive to said accumulated error signal for controlling said adjusting means.
Claim 40
Dependent Claim
119 words
The circuit of claim 36 wherein said received signal comprises a periodically occurring reference signal and including means responsive to said reference signal for estimating the S/N ratio of said received signal and means for resetting said estimating means and said accumulating means at a rate corresponding to the rate of said periodically occurring reference signal, said error signal developing means being responsive to said reference signal for developing said error signal for adjusting said selected characteristic at a first relatively rapid rate and otherwise responsive to said estimating means for developing said error signal for adjusting said selected characteristic at a rate which is less than said first rate and which is dependent upon said estimated S/N ratio.
Claim 41
Dependent Claim
65 words
A circuit for correcting errors in a received signal comprising: means for receiving a data signal including a periodically occurring reference signal; and means responsive to said reference signal for initially error correcting a selected characteristic of said received signal at a first relatively rapid rate and subsequently operable for error correcting said selected characteristic at a rate which is less than said first rate.
Claim 42
Dependent Claim
65 words
A circuit for correcting errors in a received signal comprising: means for receiving a data signal including a periodically occurring reference signal; and means responsive to said reference signal for initially error correcting a selected characteristic of said received signal at a first relatively rapid rate and subsequently operable for error correcting said selected characteristic at a rate which is less than said first rate.
Claim 43
Dependent Claim
79 words
A circuit for correcting errors in a received signal comprising: means for receiving a data signal including a periodically occurring reference signal; means for estimating the S/N ratio of said received signal; and means responsive to said reference signal for initially error correcting a selected characteristic of said received signal at a first relatively rapid rate and subsequently responsive to said estimating means for error correcting said selected characteristic at a rate which is less than said first rate.
Claim 44
Dependent Claim
79 words
A circuit for correcting errors in a received signal comprising: means for receiving a data signal including a periodically occurring reference signal; means for estimating the S/N ratio of said received signal; and means responsive to said reference signal for initially error correcting a selected characteristic of said received signal at a first relatively rapid rate and subsequently responsive to said estimating means for error correcting said selected characteristic at a rate which is less than said first rate.
Claim 45
Dependent Claim
24 words
The circuit of claim 39 wherein said estimating means is responsive to said reference signal for estimating the S/N ratio of said received signal.
Claim 46
Dependent Claim
26 words
The circuit of claim 40 including means for resetting said error correcting means at a rate corresponding to the rate of said periodically occurring reference signal.
Claim 47
Dependent Claim
88 words
A circuit for correcting errors in a received signal comprising: means for receiving a data signal comprising a plurality of successively occurring data fields each including a predetermined reference signal; means responsive to said reference signal for initially error correcting a selected characteristic of said received signal at a first relatively rapid rate and subsequently operable for error correcting said selected characteristic at a second rate not exceeding said first rate; and means for resetting said error correcting means at the beginning of each of said data fields.
Claim 48
Dependent Claim
88 words
A circuit for correcting errors in a received signal comprising: means for receiving a data signal comprising a plurality of successively occurring data fields each including a predetermined reference signal; means responsive to said reference signal for initially error correcting a selected characteristic of said received signal at a first relatively rapid rate and subsequently operable for error correcting said selected characteristic at a second rate not exceeding said first rate; and means for resetting said error correcting means at the beginning of each of said data fields.
Claim 49
Dependent Claim
15 words
The circuit of claim 42 wherein said second rate is less than said first rate.
Claim 50
Dependent Claim
39 words
The circuit of claim 42 including means for estimating the S/N ratio of said received signal and wherein said error correcting means is responsive to said estimated S/N ratio for error correcting said selected characteristic at said second rate.
Claim 51
Dependent Claim
24 words
The circuit of claim 44 wherein said estimating means is responsive to said reference signal for estimating the S/N ratio of said received signal.
Claim 52
Dependent Claim
29 words
The circuit of claim 44 wherein said error correcting means is responsive to said estimated S/N ratio for selecting said second rate from among a plurality of different rates.
Claim 53
Dependent Claim
19 words
The circuit of claim 46 wherein each of said plurality of different rates is less than said first rate.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1998-04-10 | 1998-10-10 | 1999-04-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-04-10 | 2002-10-10 | 2003-04-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-04-10 | 2006-10-10 | 2007-04-11 | $7700.00 | Window Closed / Lapsed |