US5526362A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Control of receiver station timing for time-stamped data
Assignee: Telco Systems Inc
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Filing: 1995-03-31
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Granted: 1996-06-11
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Expires: 2015-03-31
Abstract
Abstract The invention provides a method and apparatus for controlling the timing at a receiving station for the receipt of asynchronous data transmitted with a time-stamp. The received data is passed through a buffer to the remainder of the station. A decoder at the receiving station generates an indication of buffer fill level and a local time-stamp is also generated. The output timing for the buffer is controlled by a circuit which is responsive to both a difference value off, received and locally generated time-stamps and to the fill level indication.
Inventors
- 👤 Stephen M. Thompson
- 👤 Karen Brim
- 👤 Lewis Kenyon
- 👤 Hassan Ahmed
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 17:59
CPC Classifications
H; H04; H04L; H04L12/00; H04L12/54; H04L12/56; H04L12/5601; H04L12/5602; H04J; H04J3/00; H04J3/02; H04J3/06; H04J3/062; H04J3/0632; H04L1/00; H04L1/22; H04Q; H04Q11/00; H04Q11/04; H04Q11/0428; H04Q11/0478; H04L2012/5614; H04L2012/5615; H04L2012/5625; H04L2012/5627; H04L2012/5629; H04L2012/5631; H04L2012/5636; H04L2012/5638; H04L2012/5639; H04L2012/5646; H04L2012/5651
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
90 words
A device for controlling the timing at a receiving station for the receipt of asynchronous data transmitted with a time-stamp comprising: a buffer through which the received asynchronous data is passed; a decoder for generating an indication of the buffer fill level; a local time-stamp generator at the receiving station for providing locally generated time-stamps; and a circuit for controlling output timing for the buffer, said circuit being responsive to both a difference value of received and locally generated time-stamps and to an indication of fill level from said decoder.
Claim 2
Independent Claim
90 words
A device for controlling the timing at a receiving station for the receipt of asynchronous data transmitted with a time-stamp comprising: a buffer through which the received asynchronous data is passed; a decoder for generating an indication of the buffer fill level; a local time-stamp generator at the receiving station for providing locally generated time-stamps; and a circuit for controlling output timing for the buffer, said circuit being responsive to both a difference value of received and locally generated time-stamps and to an indication of fill level from said decoder.
Claim 3
Dependent Claim
30 words
A device as claimed in claim 1 wherein said fill level indication is proportional to the difference between the fill level of the buffer and a selected optimum fill level.
Claim 4
Dependent Claim
30 words
A device as claimed in claim 2 wherein the difference between current and optimum fill level is modified by a selected centering error gain to generate the fill level indication.
Claim 5
Dependent Claim
72 words
A device as claimed in claim 2 wherein said circuit includes means for generating a first difference between the time-stamp for the asynchronous data being received and the time-stamp for the most recent prior received asynchronous data, for generating a second difference between the locally generated time-stamp currently being generated and a previously generated local time-stamp, and for generating a third difference which is the difference between the first and second differences.
Claim 6
Dependent Claim
14 words
A device as claimed in claim 1 wherein the buffer is a FIFO buffer.
Claim 7
Dependent Claim
16 words
A device as claimed in claim 1 wherein the circuit includes a phase locked loop (PLL).
Claim 8
Dependent Claim
39 words
A device as claimed in claim 6 wherein an output from said PLL is obtained from a numerically controlled oscillator, a control input to the oscillator being a function of the time-stamp difference values and the fill level indication.
Claim 9
Dependent Claim
41 words
A device as claimed in claim 7 including means for indicating that a time-stamp is missing, and means responsive to said means for indicating for controlling the oscillator to move toward a selected nominal value, thereby preventing walking of the oscillator.
Claim 10
Dependent Claim
31 words
A device as claimed in claim 1 wherein said data is received in asynchronous packets, each of which packets includes a time-stamp, and wherein said buffer smooths out the received packets.
Claim 11
Independent Claim
83 words
A method for controlling timing at a receiving station for the receipt of asynchronous data transmitted with a time-stamp comprising the steps of: (a) passing the received data through a buffer; (b) generating an indication of fill level for the buffer; (c) generating a local time-stamp at the receiving station; and (d) controlling output timing for the buffer, said output timing being responsive to both a difference value of received and generated local time-stamps and to the generated indication of buffer fill level.
Claim 12
Independent Claim
83 words
A method for controlling timing at a receiving station for the receipt of asynchronous data transmitted with a time-stamp comprising the steps of: (a) passing the received data through a buffer; (b) generating an indication of fill level for the buffer; (c) generating a local time-stamp at the receiving station; and (d) controlling output timing for the buffer, said output timing being responsive to both a difference value of received and generated local time-stamps and to the generated indication of buffer fill level.
Claim 13
Dependent Claim
38 words
A method as claimed in claim 10 wherein step (b) includes the step of generating a fill level indication which is proportional to the difference between the fill level for the buffer and a selected optimum fill level.
Claim 14
Dependent Claim
35 words
A method as claimed in claim 11 wherein step (b) includes the step of modifying the difference between current and optimum fill level by a selected centering error gain to generate the fill level indication.
Claim 15
Dependent Claim
71 words
A method as claimed in claim 11 wherein step (d) includes the steps of generating a first difference between the time-stamp for the asynchronous data being received and the time-stamp for the most recent prior received asynchronous data, generating a second difference between the locally generated time-stamp currently being generated and a previously generated local time-stamp, and generating a third difference which is the difference between the first and second differences.
Claim 16
Dependent Claim
52 words
A method as claimed in claim 10 wherein step (d) is performed in a PLL, an output from said PLL being obtained from a numerically controlled oscillator, and including the step of generating a control input to the oscillator which is a function of the difference value and the fill level indication.
Claim 17
Dependent Claim
34 words
A method as claimed in claim 14 including the step, performed if a time-stamp is not received when due, of moving the oscillator toward a selected nominal value, thereby preventing walking of the oscillator.
Claim 18
Dependent Claim
36 words
A method as claimed in claim 10 wherein said data is received in asynchronous packets, each of which packets includes a time-stamp, and including the step performed by said buffer of smoothing out the received packets.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-06-11 | 1999-12-11 | 2000-06-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-06-11 | 2003-12-11 | 2004-06-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-06-11 | 2007-12-11 | 2008-06-11 | $7700.00 | Window Closed / Lapsed |