US5134404A
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Quadrature error correction
Assignee: AEROTECH Inc A CORP OF COMMONWEALTH OF
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Filing: 1991-04-01
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Granted: 1992-07-28
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Expires: 2011-04-01
Abstract
Abstract A method of correcting quadrature signal errors comprises the steps for generating an error function signal E by summing the squares of the quadrature signals and subtracting a constant K therefrom, saving the value of the error function E at θ equals approximately 0, π/2, π, and 3π/2, using the saved values of the error function to generate signals indicative of the quadrature errors, and generating corrected quadrature signals by processing the quadrature signals to eliminate the errors.
Inventors
- 👤 Robert A. Peterson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 20:36
CPC Classifications
H; H03; H03M; H03M1/00; H03M1/12; H03M1/48; H03M1/485; H04; H04L; H04L27/00; H04L27/0014; H04L2027/0016
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
169 words
A method of encoding the position of an element comprising generating electrical quadrature signals (SIN and COS) the frequency of which is indicative of the rate of change of position of the element and the lead-lag relationship of which is indicative of the direction of change of position and correcting quadrature signal errors dks, so, dkc, and Co in [two electrical] said signals where SIN=(1+dks)sin(θ)+So and COS=(1+dkc)cos(θ)+Co and wherein dks and dkc represent amplitude errors and So and Co represent bias errors comprising the steps for: a) generating an error function signal E by summing the squares of the signals SIN and COS and subtracting a constant K therefrom, b) saving the value of the error function E at θ equals approximately 0, π/2, π, ad 3π/2, c) generating signals indicative of the quadrature errors as follows: ##EQU1## d) generating corrected quadrature signals S and C by processing the signals SIN and COS as follows: S=[1/(1+dkse)] SIN-Soe, and C+[1/(1+dkse)] COS-Coe, and e) encoding the quadrature signals into position signals.
Claim 2
Independent Claim
169 words
A method of encoding the position of an element comprising generating electrical quadrature signals (SIN and COS) the frequency of which is indicative of the rate of change of position of the element and the lead-lag relationship of which is indicative of the direction of change of position and correcting quadrature signal errors dks, so, dkc, and Co in [two electrical] said signals where SIN=(1+dks)sin(θ)+So and COS=(1+dkc)cos(θ)+Co and wherein dks and dkc represent amplitude errors and So and Co represent bias errors comprising the steps for: a) generating an error function signal E by summing the squares of the signals SIN and COS and subtracting a constant K therefrom, b) saving the value of the error function E at θ equals approximately 0, π/2, π, ad 3π/2, c) generating signals indicative of the quadrature errors as follows: ##EQU1## d) generating corrected quadrature signals S and C by processing the signals SIN and COS as follows: S=[1/(1+dkse)] SIN-Soe, and C+[1/(1+dkse)] COS-Coe, and e) encoding the quadrature signals into position signals.
Claim 3
Dependent Claim
37 words
The method of claim 1 wherein steps a) to d) are repeated substituting signals S and C for SIN and COS respectively in step a) to produce a new set of corrected quadrature signals S and C.
Claim 4
Dependent Claim
29 words
The method of claim 2 wherein the steps therein are repeated until at the end of an iteration the error function E has a value below a preselected threshold.
Claim 5
Dependent Claim
15 words
The method of claim 2 wherein the steps therein are repeated continually at spaced intervals.
Claim 6
Independent Claim
170 words
A method of encoding the position of an element comprising generating electrical quadrature signals (SIN and COS) the frequency of which is indicative of the rate of change of position of the element and the lead-lag relationship of which is indicative of the direction of change of position and correcting quadrature signal errors dks, So, dkc, Co and φ in said signals where SIN=(1+dks)sin(θ)+So and COS=(1+dkc)cos(θ+φ)+Co and wherein dks and dkc represent amplitude errors and So and Co represent bias errors comprising the steps for: a) generating an error function signal E by summing the squares of the signals SIN and COS and subtracting a constant K therefrom, b) saving the value of the error function E at θ equals approximately 0, π/4, π/2, 3π/4, π, and 3π/2, c) generating signals indicative of the quadrature errors as follows: ##EQU2## d) generating corrected quadrature signals S and C by processing the signals SIN and COS as follows: S=[1/(1+dkse)] SIN-Soe, and C=[1/(1+dkse)] COS-φes-Coe, and e) encoding the quadrature signals into position signals.
Claim 7
Independent Claim
170 words
A method of encoding the position of an element comprising generating electrical quadrature signals (SIN and COS) the frequency of which is indicative of the rate of change of position of the element and the lead-lag relationship of which is indicative of the direction of change of position and correcting quadrature signal errors dks, So, dkc, Co and φ in said signals where SIN=(1+dks)sin(θ)+So and COS=(1+dkc)cos(θ+φ)+Co and wherein dks and dkc represent amplitude errors and So and Co represent bias errors comprising the steps for: a) generating an error function signal E by summing the squares of the signals SIN and COS and subtracting a constant K therefrom, b) saving the value of the error function E at θ equals approximately 0, π/4, π/2, 3π/4, π, and 3π/2, c) generating signals indicative of the quadrature errors as follows: ##EQU2## d) generating corrected quadrature signals S and C by processing the signals SIN and COS as follows: S=[1/(1+dkse)] SIN-Soe, and C=[1/(1+dkse)] COS-φes-Coe, and e) encoding the quadrature signals into position signals.
Claim 8
Dependent Claim
37 words
The method of claim 5 wherein steps a) to d) are repeated substituting signals S and C for SIN and COS respectively in step a) to produce a new set of corrected quadrature signals S and C.
Claim 9
Dependent Claim
29 words
The method of claim 6 wherein the steps therein are repeated until at the end of an iteration the error function E has a value below a preselected threshold.
Claim 10
Dependent Claim
15 words
The method of claim 7 wherein the steps therein are repeated continually at spaced intervals.
Claim 11
Independent Claim
179 words
A system of encoding the position of an element comprising generating electrical quadrature signals (SIN and COS) the frequency of which is indicative of the rate of change of position of the element and the lead-lag relationship of which is indicative of the direction of change of position and correcting quadrature signal errors dks, So, dkc, and Co in said signals where SIN=(1+dks)sin(θ)+So and COS=(1+dkc)cos(θ)+Co and wherein dks and dkc represent amplitude errors and So and Co represent bias errors comprising: a) circuit means for generating an error function signal E by summing the squares of the signals SIN and COS and subtracting a constant C therefrom, b) circuit means for saving the value of the error function E at θ equals approximately 0, π/2, π, and 3π/2, c) circuit means for generating signals indicative of the quadrature errors as follows: ##EQU3## d) circuit means for generating corrected quadrature signals S and C by processing the signals SIN and COS as follows: S=[1/(1+dkse)] SIN-Soe, and C=[1/(1+dkse)] COS-Coe, and e) circuit means for encoding the quadrature signals into position signals.
Claim 12
Independent Claim
179 words
A system of encoding the position of an element comprising generating electrical quadrature signals (SIN and COS) the frequency of which is indicative of the rate of change of position of the element and the lead-lag relationship of which is indicative of the direction of change of position and correcting quadrature signal errors dks, So, dkc, and Co in said signals where SIN=(1+dks)sin(θ)+So and COS=(1+dkc)cos(θ)+Co and wherein dks and dkc represent amplitude errors and So and Co represent bias errors comprising: a) circuit means for generating an error function signal E by summing the squares of the signals SIN and COS and subtracting a constant C therefrom, b) circuit means for saving the value of the error function E at θ equals approximately 0, π/2, π, and 3π/2, c) circuit means for generating signals indicative of the quadrature errors as follows: ##EQU3## d) circuit means for generating corrected quadrature signals S and C by processing the signals SIN and COS as follows: S=[1/(1+dkse)] SIN-Soe, and C=[1/(1+dkse)] COS-Coe, and e) circuit means for encoding the quadrature signals into position signals.
Claim 13
Dependent Claim
19 words
The system according to claim 9 wherein the circuit means comprise a combination of analog and digital circuit elements.
Claim 14
Dependent Claim
18 words
The system according to claim 10 wherein the digital circuit elements include a microcomputer or digital signal processor.
Claim 15
Independent Claim
206 words
A system of encoding the position of an element comprising generating electrical quadrature signals (SIN and COS) the frequency of which is indicative of the rate of change of position of the element and the lead-lag relationship of which is indicative of the direction of change of position and correcting quadrature signal errors dks, So, dkc, Co and in said signals where SIN+(1+dks)sin(θ)+So and COS=(1+dkc)cos(θ+φ)+Co and wherein dks and dkc represent amplitude errors and So and Co represent bias errors comprising: a) circuit means for generating an error function signal E by summing the squares of the signals SIN and COS and subtracting a constant C therefrom, b) circuit means for generating an error function signal E by summing the squares of the signals SIN and COS and subtracting a constant C therefrom, b) circuit means for saving the value of the error function E at θ equals approximately 0, π/4, π/2, 3π/4, πand 3π/2, c) circuit means for generating signals indicative of the quadrature errors as follows: ##EQU4## d) circuit means for generating corrected quadrature signals S and C by processing the signals SIN and COS as follows: S=[1/(1+dkse)] SIN-Soe, and C=[1/(1+dkse)] COS-φes-Coe, and e) circuit means for encoding the quadrature signals into position signals.
Claim 16
Independent Claim
206 words
A system of encoding the position of an element comprising generating electrical quadrature signals (SIN and COS) the frequency of which is indicative of the rate of change of position of the element and the lead-lag relationship of which is indicative of the direction of change of position and correcting quadrature signal errors dks, So, dkc, Co and in said signals where SIN+(1+dks)sin(θ)+So and COS=(1+dkc)cos(θ+φ)+Co and wherein dks and dkc represent amplitude errors and So and Co represent bias errors comprising: a) circuit means for generating an error function signal E by summing the squares of the signals SIN and COS and subtracting a constant C therefrom, b) circuit means for generating an error function signal E by summing the squares of the signals SIN and COS and subtracting a constant C therefrom, b) circuit means for saving the value of the error function E at θ equals approximately 0, π/4, π/2, 3π/4, πand 3π/2, c) circuit means for generating signals indicative of the quadrature errors as follows: ##EQU4## d) circuit means for generating corrected quadrature signals S and C by processing the signals SIN and COS as follows: S=[1/(1+dkse)] SIN-Soe, and C=[1/(1+dkse)] COS-φes-Coe, and e) circuit means for encoding the quadrature signals into position signals.
Claim 17
Dependent Claim
19 words
The system according to claim 12 wherein the circuit means comprise a combination of analog and digital circuit elements.
Claim 18
Dependent Claim
18 words
The system according to claim 13 wherein the digital circuit elements include a microcomputer or digital signal processor.
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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) | 1995-07-28 | 1996-01-27 | 1996-07-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-07-28 | 2000-01-27 | 2000-07-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-07-28 | 2004-01-27 | 2004-07-28 | $7700.00 | Window Closed / Lapsed |