US5960044A
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Apparatus and method for block phase estimation
Assignee: Cisco Technology Inc
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Filing: 1996-11-14
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Granted: 1999-09-28
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Expires: 2016-11-14
Abstract
Abstract A block phase estimator include a phase averaging circuit. A first embodiment of the phase averaging circuit includes a phase differencing circuit coupled to an averager input, a first modulo circuit coupled to the phase differencing circuit, a filter coupled to the first modulo circuit, and a summation circuit having an positive input and a negative input, the positive input being coupled to the averager input, the negative input being coupled to the filter. The phase averaging circuit further includes a second modulo circuit coupled to the summation circuit. An alternative embodiment of the phase averaging circuit includes a delay line having a plurality of taps coupled to an averager input and a plurality of first subtractor circuits, a first input of each first subtractor circuit being coupled to the averager input, a second input of each first subtractor circuit being coupled to a corresponding tap of the plurality of taps. A plurality of first modulo circuits are coupled to the plurality of first subtractor circuits, each first modulo circuit being coupled to a corresponding first subtractor circuit. A summation circuit is coupled to all first modulo circuits, and a scaling circuit is coupled to the summation circuit. The phase averaging circuit further includes a second subtractor circuit, a first input of the second subtractor circuit being coupled to the averager input, a second input of the second subtractor circuit being coupled to the scaling circuit.
Inventors
- 👤 Leo Montreuil
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 00:45
CPC Classifications
H; H04; H04L; H04L27/00; H04L27/18; H04L27/22; H04L27/233; H04L27/2332; H03; H03D; H03D3/00; H03D3/006; H03D3/007; H04L27/0014; H04L2027/0024; H04L2027/0026; H04L2027/003; H04L2027/0044; H04L2027/0046; H04L2027/0063; H04L2027/0067; H04L2027/0069
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
65 words
In a phase estimator, a phase averaging circuit comprising: a phase differencing circuit coupled to an averager input; a first modulo circuit coupled to the phase differencing circuit; a filter coupled to the first modulo circuit; and a summation circuit having an positive input and a negative input, the positive input being coupled to the averager input, the negative input being coupled to the filter.
Claim 2
Dependent Claim
65 words
In a phase estimator, a phase averaging circuit comprising: a phase differencing circuit coupled to an averager input; a first modulo circuit coupled to the phase differencing circuit; a filter coupled to the first modulo circuit; and a summation circuit having an positive input and a negative input, the positive input being coupled to the averager input, the negative input being coupled to the filter.
Claim 3
Dependent Claim
16 words
The circuit of claim 1, further comprising a second modulo circuit coupled to the summation circuit.
Claim 4
Dependent Claim
65 words
The circuit of claim 1, wherein the filter comprises: a delay line having a plurality of taps; a plurality of multipliers, each multiplier having first and second inputs, the first input of each multiplier being coupled to a corresponding tap, a predetermined filter coefficient being provided to the second input of each multiplier; and a filter summer being coupled to an output of each multiplier.
Claim 5
Dependent Claim
77 words
The circuit of claim 3, wherein: a number of samples to be averaged is N; a number of multipliers is N-1; each multiplier is identified by an index k where k is greater than zero and k is less than or equal to N; a uniformly weighted phase average is sought where h n is an inverse of N; and the predetermined filter coefficient provided to the kth multiplier is A k and is given by: ##EQU3##
Claim 6
Dependent Claim
90 words
In a phase estimator, a method of feed forward phase averaging comprising steps of: receiving a signal with a plurality of samples, each with an associated phase: forming a phase difference measurement between a current phase measurement of a selected sample and an adjacent phase measurement of a sample adjacent to the selected sample; transforming the phase difference measurement into a differenced phase measurement between -π and π radians; filtering the differenced phase measurement; and forming a subtracted phase by subtracting the differenced phase measurement from the current phase measurement.
Claim 7
Dependent Claim
90 words
In a phase estimator, a method of feed forward phase averaging comprising steps of: receiving a signal with a plurality of samples, each with an associated phase: forming a phase difference measurement between a current phase measurement of a selected sample and an adjacent phase measurement of a sample adjacent to the selected sample; transforming the phase difference measurement into a differenced phase measurement between -π and π radians; filtering the differenced phase measurement; and forming a subtracted phase by subtracting the differenced phase measurement from the current phase measurement.
Claim 8
Dependent Claim
22 words
The method of claim 5, further comprising a step of transforming the subtracted phase into a phase between -π and π radians.
Claim 9
Dependent Claim
38 words
The method of claim 5, wherein the step of filtering comprises steps of: forming a plurality of adjacent phase measurements; separately multiplying each adjacent phase measurement by a corresponding predetermined filter coefficient; and a summing all multiplication results.
Claim 10
Dependent Claim
79 words
The method of claim 7, wherein: a number of phase measurements to be averaged is N; a number of adjacent phase measurements is N-1; each predetermined filter coefficient is identified by an index k where k is greater than zero and k is less than or equal to N; a uniformly weighted phase average is sought where h n is an inverse of N; and the k th predetermined filter coefficient is A k and is given by: ##EQU4##
Claim 11
Dependent Claim
129 words
In a phase estimator, a phase averaging circuit comprising: a delay line having a plurality of taps coupled to an averager input; a plurality of first subtractor circuits, a first input of each first subtractor circuit being coupled to the averager input, a second input of each first subtractor circuit being coupled to a corresponding tap of the plurality of taps; a plurality of first modulo circuits, each first modulo circuit being coupled to a corresponding first subtractor circuit; a summation circuit coupled to all first modulo circuits; a scaling circuit coupled to the summation circuit; and a second subtractor circuit, a first input of the second subtractor circuit being coupled to the averager input, a second input of the second subtractor circuit being coupled to the scaling circuit.
Claim 12
Dependent Claim
129 words
In a phase estimator, a phase averaging circuit comprising: a delay line having a plurality of taps coupled to an averager input; a plurality of first subtractor circuits, a first input of each first subtractor circuit being coupled to the averager input, a second input of each first subtractor circuit being coupled to a corresponding tap of the plurality of taps; a plurality of first modulo circuits, each first modulo circuit being coupled to a corresponding first subtractor circuit; a summation circuit coupled to all first modulo circuits; a scaling circuit coupled to the summation circuit; and a second subtractor circuit, a first input of the second subtractor circuit being coupled to the averager input, a second input of the second subtractor circuit being coupled to the scaling circuit.
Claim 13
Dependent Claim
17 words
The circuit of claim 9, further comprising a second modulo circuit coupled to the second subtractor circuit.
Claim 14
Dependent Claim
26 words
The circuit of claim 9, wherein the scaling circuit multiplies an input to be scaled by an inverse of a number of samples to be averaged.
Claim 15
Dependent Claim
29 words
The circuit of claim 9, wherein: a modulation carrier has a period T; and the delay line includes at least four taps representing phases sampled during the period T.
Claim 16
Dependent Claim
120 words
In a phase estimator, a method of feed forward phase averaging comprising steps of: receiving a signal with a plurality of samples, each with an associated phase: forming a plurality of adjacent phase measurements; forming a plurality of first subtracted phase measurements by subtracting each adjacent phase measurement from a current phase measurement the current phase being selected from the plurality of adjacent phases; forming a plurality of first modulo phases by transforming each first subtracted phase measurement into a phase between -π and π radians; forming a summed phase measurement by summing all first modulo phases; scaling the summed phase measurement; and forming a second subtracted phase measurement by subtracting the scaled phase measurement from the current phase measurement.
Claim 17
Dependent Claim
120 words
In a phase estimator, a method of feed forward phase averaging comprising steps of: receiving a signal with a plurality of samples, each with an associated phase: forming a plurality of adjacent phase measurements; forming a plurality of first subtracted phase measurements by subtracting each adjacent phase measurement from a current phase measurement the current phase being selected from the plurality of adjacent phases; forming a plurality of first modulo phases by transforming each first subtracted phase measurement into a phase between -π and π radians; forming a summed phase measurement by summing all first modulo phases; scaling the summed phase measurement; and forming a second subtracted phase measurement by subtracting the scaled phase measurement from the current phase measurement.
Claim 18
Dependent Claim
25 words
The method of claim 13, further comprising an additional step of transforming the second subtracted phase measurement into a phase between -π and π radians.
Claim 19
Dependent Claim
27 words
The method of claim 13, wherein the step of scaling multiplies an input to be scaled by an inverse of a number of samples to be averaged.
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| 7.5 Years (Year 8) | 2006-09-27 | 2007-03-29 | 2007-09-28 | $3760.00 | Window Closed / Lapsed |
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