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US5095263A
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Anti-aliasing for frequency output sensors
Assignee: Honeywell International Inc
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Filing: 1990-06-11
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Granted: 1992-03-10
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Expires: 2010-06-11
Abstract
Abstract A technique for reducing the effects of aliasing in a frequency output sensor system. The system includes a sensor for producing a sensor output signal at a frequency that varies within a modulation range as a function of an input parameter. The system also includes a processor for measuring the frequency of the sensor output signal at a sequence of sample times. The invention provides an analog filter for filtering the sensor output signal. In a first embodiment, the filter has an increasing phase lag versus frequency characteristic within the modulation range. In a second embodiment, the filter comprises a phase lock loop having frequency dividers in the input signal path and in the feedback path.
Inventors
- 👤 Rex B. Peters
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 14:36
CPC Classifications
G; G01; G01D; G01D5/00; G01D5/12; G01D5/244; G01D5/248; G01R; G01R23/00; H; H03; H03L; H03L7/00; H03L7/06; H03L7/16; H03L7/18; H03L7/183
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
91 words
In a system for measuring an input parameter, the system including sensor means for producing a sensor output signal at a frequency that varies within a modulation range as a function of the input parameter, and processing means for measuring the frequency of the sensor output signal at a sequence of sample times, the improvement comprising an analog filter for filtering the sensor output signal, the filter being connected between the sensor means and the processing means, the filter having an increasing phase lag versus frequency characteristic within the modulation range.
Claim 2
Dependent Claim
91 words
In a system for measuring an input parameter, the system including sensor means for producing a sensor output signal at a frequency that varies within a modulation range as a function of the input parameter, and processing means for measuring the frequency of the sensor output signal at a sequence of sample times, the improvement comprising an analog filter for filtering the sensor output signal, the filter being connected between the sensor means and the processing means, the filter having an increasing phase lag versus frequency characteristic within the modulation range.
Claim 3
Dependent Claim
16 words
The improvement of claim 1, wherein the filter has a low pass amplitude versus frequency characteristic.
Claim 4
Dependent Claim
21 words
The improvement of claim 1, wherein the filter has a substantially linear phase lag versus frequency characteristic within the modulation range.
Claim 5
Dependent Claim
26 words
The improvement of claim 2, wherein the amplitude versus frequency characteristic has a 3dB point at a frequency approximately in the center of the modulation range.
Claim 6
Dependent Claim
161 words
In a system for measuring an input parameter, the system including sensor means for producing a sensor output signal at a frequency that varies within a modulation range as a function of the input parameter, and processing means for measuring the frequency of the sensor output signal at a sequence of sample times, the improvement comprising an analog filter for filtering the sensor output signal, the filter being connected between the sensor means and the processing means, the filter comprising a phase lock loop that includes a phase comparator having first and second input terminals, a low pass filter, a voltage-controlled oscillator having an output terminal, a feedback path coupling the output terminal of the voltage-controlled oscillator to the first input terminal of the phase comparator, a divide by N circuit coupled between the sensor means and the second phase comparator input terminal, and a divide by K circuit in the feedback path, K being greater than or equal to N.
Claim 7
Dependent Claim
161 words
In a system for measuring an input parameter, the system including sensor means for producing a sensor output signal at a frequency that varies within a modulation range as a function of the input parameter, and processing means for measuring the frequency of the sensor output signal at a sequence of sample times, the improvement comprising an analog filter for filtering the sensor output signal, the filter being connected between the sensor means and the processing means, the filter comprising a phase lock loop that includes a phase comparator having first and second input terminals, a low pass filter, a voltage-controlled oscillator having an output terminal, a feedback path coupling the output terminal of the voltage-controlled oscillator to the first input terminal of the phase comparator, a divide by N circuit coupled between the sensor means and the second phase comparator input terminal, and a divide by K circuit in the feedback path, K being greater than or equal to N.
Claim 8
Dependent Claim
11 words
The system of claim 5, where K is equal to N.
Claim 9
Dependent Claim
28 words
The system of claim 5, where K is equal to MN and M is an integer, whereby the frequency of the sensor output signal is multiplied by M.
Claim 10
Dependent Claim
77 words
An anti-aliasing method for a system that includes sensor means for producing a sensor output signal at a frequency that varies within a modulation range as a function of an input parameter, and processing means for measuring the frequency of the sensor output signal at a sequence of sample times, the method comprising analog filtering the sensor output signal by means of a filter that has an increasing phase lag versus frequency characteristic within the modulation range.
Claim 11
Dependent Claim
77 words
An anti-aliasing method for a system that includes sensor means for producing a sensor output signal at a frequency that varies within a modulation range as a function of an input parameter, and processing means for measuring the frequency of the sensor output signal at a sequence of sample times, the method comprising analog filtering the sensor output signal by means of a filter that has an increasing phase lag versus frequency characteristic within the modulation range.
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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) | 1995-03-10 | 1995-09-09 | 1996-03-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-03-10 | 1999-09-09 | 2000-03-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-03-10 | 2003-09-09 | 2004-03-10 | $7700.00 | Window Closed / Lapsed |