Patent US4549165A successfully refreshed from Google Patents.
US4549165A
Expired / Lapsed
US
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Dynamic voltage reference apparatus for A/D converters
Assignee: Boeing North American Inc
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Filing: 1984-06-22
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Granted: 1985-10-22
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Expires: 2004-06-22
Abstract
Abstract When an A/D converter is converting a multilevel analog signal into a plurality of distinct digital words, it needs to have a very accurate reference voltage which is tied to the voltage levels of the analog signal being converted for high accuracy. The present invention takes the most significant bit and an error bit signal from the analog-to-digital converter and logically combines these signals in such a way that error feedback signals are generated which are integrated over the long term and used to adjust the reference voltages supplied to the analog-to-digital converter wherein the feedback error signals average to zero.
Inventors
- 👤 Michael Brian
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 04:32
CPC Classifications
H; H03; H03M; H03M1/00; H03M1/12; H03M1/50; H03M1/504; H03M1/506; H03M1/06; H03M1/0602; H03M1/0604
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
123 words
Dynamic voltage reference apparatus comprising, in combination: analog-to-digital (A/D) conversion first means, including signal input means, positive and negative voltage reference source means and digital word output means, for detecting analog signal input amplitude values with respect to a predetermined reference level; logic circuit second means, connected to said word output means of said first means for receiving error bit and most significant bit (msb) signals therefrom, for supplying positive and negative feedback signals from output means thereof; and reference voltage third means, connected between said first and second means, for integrating the feedback signals and adjusting the positive and negative voltage levels of reference signals applied to said first means toward a value which minimizes the average value of said feedback signals.
Claim 2
Dependent Claim
123 words
Dynamic voltage reference apparatus comprising, in combination: analog-to-digital (A/D) conversion first means, including signal input means, positive and negative voltage reference source means and digital word output means, for detecting analog signal input amplitude values with respect to a predetermined reference level; logic circuit second means, connected to said word output means of said first means for receiving error bit and most significant bit (msb) signals therefrom, for supplying positive and negative feedback signals from output means thereof; and reference voltage third means, connected between said first and second means, for integrating the feedback signals and adjusting the positive and negative voltage levels of reference signals applied to said first means toward a value which minimizes the average value of said feedback signals.
Claim 3
Independent Claim
92 words
The method of adjusting reference voltage levels to a multilevel analog-to-digital (A/D) converter for minimizing signal level detection errors comprising the steps of: logically combining the most significant bit (msb) and a clock signal to provide one of a positive strobe signal and a negative strobe signal; logically combining an error bit signal and said positive and negative strobe signals to produce one of a positive and negative error feedback signal; and integrating said positive and negative error feedback signals to provide reference voltage signals for use by a multilevel A/D converter.
Claim 4
Independent Claim
92 words
The method of adjusting reference voltage levels to a multilevel analog-to-digital (A/D) converter for minimizing signal level detection errors comprising the steps of: logically combining the most significant bit (msb) and a clock signal to provide one of a positive strobe signal and a negative strobe signal; logically combining an error bit signal and said positive and negative strobe signals to produce one of a positive and negative error feedback signal; and integrating said positive and negative error feedback signals to provide reference voltage signals for use by a multilevel A/D converter.
Claim 5
Dependent Claim
169 words
Dynamic voltage level supply apparatus for use with an analog-to-digital (A/D) signal converting device comprising, in combination: signal supplying first means for supplying most significant error and word bits output by a D/A converter as a result of an analog signal conversion; logic circuit second means, including error signal first and second output means and input means connected to said first means for receiving said most significant error and word bits therefrom, passing an inverted version of said error bit to said error signal first output means when the most significant bit is a logic one and passing an inverted version of said error bit to said error signal second output means when the most significant bit is a logic zero; and integrating third means, including first and second input means connected to said error signal first and second output means of said logic circuit second means and including controlled voltage output means, said integrating third means providing positive and negative voltage references for use by the D/A converter.
Claim 6
Dependent Claim
169 words
Dynamic voltage level supply apparatus for use with an analog-to-digital (A/D) signal converting device comprising, in combination: signal supplying first means for supplying most significant error and word bits output by a D/A converter as a result of an analog signal conversion; logic circuit second means, including error signal first and second output means and input means connected to said first means for receiving said most significant error and word bits therefrom, passing an inverted version of said error bit to said error signal first output means when the most significant bit is a logic one and passing an inverted version of said error bit to said error signal second output means when the most significant bit is a logic zero; and integrating third means, including first and second input means connected to said error signal first and second output means of said logic circuit second means and including controlled voltage output means, said integrating third means providing positive and negative voltage references for use by the D/A converter.
Claim 7
Dependent Claim
51 words
Apparatus as claimed in claim 3 comprising, in addition: D/A converter means, connected to said first and third means and including analog signal input means, for converting multilevel analog input signals to digital word and error bit output signals using the voltage levels obtained from said third means as a reference.
Claim 8
Independent Claim
108 words
The method of compensating for errors introduced in the conversion of a multilevel analog signal having a discrete number of levels to a digital signal when the maximum possible analog signal level varies from any of its predefined absolute values comprising, the steps of: logically decoding the most significant digital word bit and the most significant error bit generated in an analog-to-digital conversion of the multilevel analog signal for generating a controlled amplitude comparison level reference signal; and using the controlled amplitude signal as a comparison level reference for converting the multilevel analog signal to one of the discrete number of possible digital values representing that analog value.
Claim 9
Independent Claim
108 words
The method of compensating for errors introduced in the conversion of a multilevel analog signal having a discrete number of levels to a digital signal when the maximum possible analog signal level varies from any of its predefined absolute values comprising, the steps of: logically decoding the most significant digital word bit and the most significant error bit generated in an analog-to-digital conversion of the multilevel analog signal for generating a controlled amplitude comparison level reference signal; and using the controlled amplitude signal as a comparison level reference for converting the multilevel analog signal to one of the discrete number of possible digital values representing that analog value.
Claim 10
Dependent Claim
175 words
Compensation apparatus comprising, in combination: first means for supplying a multilevel analog signal to be converted to digital values, the analog signal having predefined intermediate values relative the maximum and minimum levels thereof although the maximum and minimum absolute may vary; analog-to-digital (A/D) conversion second means, including voltage reference signal means, digital signal word and error bit output means and signal input means connected to said first means, for converting multilevel analog signals received from said first means to digital bit words having digital values directly based on the received analog signal value relative the level of voltage reference signals supplied thereto; and feedback control means, connected between said digital word and error bit output means of said second means and said voltage reference signal means, for logically detecting the most significant bit of the digital word and the error bit values output by said second means at that time and controlling the level of the reference voltage supplied to said second means toward a value which provides an average error bit value of zero.
Claim 11
Dependent Claim
175 words
Compensation apparatus comprising, in combination: first means for supplying a multilevel analog signal to be converted to digital values, the analog signal having predefined intermediate values relative the maximum and minimum levels thereof although the maximum and minimum absolute may vary; analog-to-digital (A/D) conversion second means, including voltage reference signal means, digital signal word and error bit output means and signal input means connected to said first means, for converting multilevel analog signals received from said first means to digital bit words having digital values directly based on the received analog signal value relative the level of voltage reference signals supplied thereto; and feedback control means, connected between said digital word and error bit output means of said second means and said voltage reference signal means, for logically detecting the most significant bit of the digital word and the error bit values output by said second means at that time and controlling the level of the reference voltage supplied to said second means toward a value which provides an average error bit value of zero.
Claim 12
Independent Claim
91 words
The method of compensating for variations in maximum amplitude of a previously amplitude modulated multilevel analog signal to be converted to a digital signal comprising, the steps of: detecting the digital logic value error bit output from the analog-to-digital (A/D) converter; and controlling the reference voltage level used by the A/D converter for directly outputting a digital word based on the relative amplitude of the analog signal to be converted and the reference voltage level to obtain an average digital error bit value of zero over a predetermined period of time.
Claim 13
Independent Claim
91 words
The method of compensating for variations in maximum amplitude of a previously amplitude modulated multilevel analog signal to be converted to a digital signal comprising, the steps of: detecting the digital logic value error bit output from the analog-to-digital (A/D) converter; and controlling the reference voltage level used by the A/D converter for directly outputting a digital word based on the relative amplitude of the analog signal to be converted and the reference voltage level to obtain an average digital error bit value of zero over a predetermined period of time.
Claim 14
Dependent Claim
85 words
Apparatus for compensating for variations in maximum amplitude of a previously amplitude modulated multilevel analog signal to be converted to a digital signal comprising, in combination: first means, connected to the output of an analog-to-digital converter for receiving error bit signals therefrom, for detecting a digital logic value error bit output from an analog-to-digital converter; and logical control second means, connected to said first means, for controlling the reference voltage level supplied to the analog-to-digital converter to obtain an average error bit value of zero.
Claim 15
Dependent Claim
85 words
Apparatus for compensating for variations in maximum amplitude of a previously amplitude modulated multilevel analog signal to be converted to a digital signal comprising, in combination: first means, connected to the output of an analog-to-digital converter for receiving error bit signals therefrom, for detecting a digital logic value error bit output from an analog-to-digital converter; and logical control second means, connected to said first means, for controlling the reference voltage level supplied to the analog-to-digital converter to obtain an average error bit value of zero.
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) | 1988-10-21 | 1989-04-22 | 1989-10-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-10-21 | 1993-04-22 | 1993-10-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-10-21 | 1997-04-22 | 1997-10-22 | $7700.00 | Window Closed / Lapsed |