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Measurement of bladed rotors and, more particularly, speed measurement of bladed rotors in a turbine engine using microwave probes is described. In one embodiment, an apparatus for measuring bladed includes a microwave sensor that radiates a microwave signal toward a bladed rotor and receives a refl

Measurement of bladed rotors and, more particularly, speed measurement of bladed rotors in a turbine engine using microwave probes is described. In one embodiment, an apparatus for measuring bladed includes a microwave sensor that radiates a microwave signal toward a bladed rotor and receives a reflected microwave signal from the bladed rotor, a radio frequency module that generates the microwave signal radiated by the microwave sensor and down-converts the reflected microwave signal into a down-converted signal, and a main processing module configured to generate an output pulse train signal representative of a speed of the bladed rotor based on the down-converted signal. In another embodiment, a method for measuring bladed rotors is described including radiating a microwave signal, receiving a reflected microwave signal, down-converting the reflected microwave signal, and generating an output pulse train signal representative of a speed of a bladed rotor based on the down-converted signal.

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1. An apparatus for measuring an angular speed of a bladed rotor, comprising: a microwave sensor configured to radiate a continuous-wave microwave signal toward the bladed rotor and receive a reflected microwave signal from the bladed rotor;a radio frequency module that generates the continuous-wave

1. An apparatus for measuring an angular speed of a bladed rotor, comprising: a microwave sensor configured to radiate a continuous-wave microwave signal toward the bladed rotor and receive a reflected microwave signal from the bladed rotor;a radio frequency module that generates the continuous-wave microwave signal radiated by the microwave sensor and down-converts the reflected microwave signal into a down-converted signal; anda main processing module configured to generate an output pulse train signal representative of the angular speed of the bladed rotor based on one of an in-phase portion or a quadrature portion of the down-converted signal. 2. The apparatus of claim 1, wherein the main processing module comprises a bank of sub-band filters, a signal energy detector, a bank of sub-band energy detectors, a sub-band selector, and an in-phase/quadrature output selector. 3. The apparatus of claim 2, wherein the signal energy detector comprises an in-phase energy detector that detects a mean energy of the in-phase portion of the down-converted signal, a quadrature energy detector that detects a mean energy of the quadrature portion of the down-converted signal, and a summer that sums the mean energy of the in-phase portion of the down-converted signal and the mean energy of the quadrature portion of the down-converted signal as a total mean energy of the down-converted signal. 4. The apparatus of claim 3, wherein the bank of sub-band filters comprises a plurality of sub-band filter pairs,each sub-band filter pair comprises an in-phase sub-band filter and a quadrature sub-band filter,each in-phase sub-band filter comprises a band-pass filter that provides an in-phase band-passed signal based on the in-phase portion of the down converted signal, a mean energy detector that detects a mean energy of the in-phase band-passed signal, and a zero-crossing detector that detects zero-crossings of the in-phase band-passed signal and generates an in-phase pulse train signal based on the zero-crossings of the in-phase band-passed signal, andeach quadrature sub-band filter comprises a band-pass filter that provides a quadrature band-passed signal based on the quadrature portion of the down converted signal, a mean energy detector that detects a mean energy of the quadrature band-passed signal, and a zero-crossing detector that detects zero-crossings of the quadrature band-passed signal and generates a quadrature pulse train signal based on the zero-crossings of the quadrature band-passed signal. 5. The apparatus of claim 4, wherein the bank of sub-band energy detectors comprises a plurality of sub-band energy detectors, andeach sub-band energy detector comprises another summer that sums the mean energy of the in-phase band-passed signal and the mean energy of the quadrature band-passed signal from a respective in-phase and quadrature sub-band filter pair as a total mean sub-band energy, and a comparator that compares the total mean sub-band energy to the total mean energy of the down-converted signal and provides a sub-band selection signal. 6. The apparatus of claim 5, wherein the sub-band selector comprises selection logic, an in-phase sub-band selector, and a quadrature sub-band selector,the selection logic generates control signals for the in-phase sub-band selector and the quadrature sub-band selector based on the sub-band selection signals from the sub-band energy detectors,the in-phase sub-band selector selects an in-phase pulse train signal among the in-phase pulse train signals generated from the in-phase sub-band filters for output as a selected in-phase pulse train signal based on the control signals, andthe quadrature-phase sub-band selector selects a quadrature pulse train signal among the quadrature pulse train signals generated from the quadrature sub-band filters for output as a selected quadrature pulse train signal based on the control signals. 7. The apparatus of claim 6, wherein the in-phase/quadrature output selector outputs one of the selected in-phase pulse train signal and the selected quadrature pulse train signal as the output pulse train signal representative of the speed of the bladed rotor. 8. The apparatus of claim 6, wherein the in-phase/quadrature output selector is configured to select one of the selected in-phase pulse train signal and the selected quadrature pulse train signal for output as the output pulse train signal representative of the speed of the bladed rotor, andmaintain the selection of the one of the pulse train signals for output until a predetermined number of falling or rising edges occurs on another one of the pulse train signals while no falling or rising edges occur on the selected one of the pulse train signals. 9. A method for measuring an angular speed of a bladed rotor, comprising: radiating a continuous-wave microwave signal toward the bladed rotor;receiving a reflected microwave signal from the bladed rotor;down-converting the reflected microwave signal into a down-converted signal; andgenerating an output pulse train signal representative of the angular speed of the bladed rotor based on one of an in-phase portion or a quadrature portion of the down-converted signal. 10. The method of claim 9, wherein generating the output pulse train signal further comprises detecting a mean energy of the in-phase portion of the down-converted signal and a mean energy of the quadrature portion of the down-converted signal;summing the mean energy of the in-phase portion of the down-converted signal and the mean energy of the quadrature portion of the down-converted signal as a total mean energy of the down-converted signal. 11. The method of claim 10, wherein generating the output pulse train signal further comprises, for each of a plurality of sub-bands of the down-converted signal, band-pass filtering the in-phase portion of the down-converted signal to provide an in-phase band-passed signal;detecting a mean energy of the in-phase band-passed signal;detecting zero-crossings of the in-phase band-passed signal;generating an in-phase pulse train signal based on the zero-crossings of the in-phase band-passed signal;band-pass filtering the quadrature portion of the down-converted signal to provide a quadrature band-passed signal;detecting a mean energy of the quadrature band-passed signal;detecting zero-crossings of the quadrature band-passed signal; andgenerating a quadrature pulse train signal based on the zero-crossings of the quadrature band-passed signal. 12. The method of claim 11, wherein generating the output pulse train signal further comprises, for each of the plurality of sub-bands of the down-converted signal, summing the mean energies of the in-phase and quadrature band-passed signals as a total mean sub-band energy; andcomparing the total mean sub-band energy to the total mean energy of the down-converted signal to provide a sub-band selection signal. 13. The method of claim 12, wherein generating the output pulse train signal further comprises generating control signals based on the sub-band selection signals;selecting an in-phase pulse train signal among the in-phase pulse train signals of the plurality of sub-bands for output as a selected in-phase pulse train signal based on the control signals; andselecting a quadrature pulse train signal among the quadrature pulse train signals of the plurality of sub-bands for output as a selected quadrature pulse train signal based on the control signals. 14. The method of claim 13, wherein generating the output pulse train signal further comprises selecting one of the selected in-phase pulse train signal and the selected quadrature pulse train signal as the output pulse train signal representative of the speed of the bladed rotor. 15. An apparatus for measuring an angular speed of a bladed rotor, comprising: a microwave sensor configured to radiate a continuous-wave microwave signal toward the bladed rotor and receives a reflected microwave signal from the bladed rotor;a radio frequency module that generates the continuous-wave microwave signal radiated by the microwave sensor and down-converts the reflected microwave signal into a down-converted signal; anda main processing module comprising a band-pass filter, a tracking filter, a digital pulse generator, and an in-phase/quadrature output selector, the main processing module being configured to generate an output pulse train signal representative of the angular speed of the bladed rotor based on the down-converted signal. 16. The apparatus of claim 15, wherein the band-pass filter passes frequencies of the down-converted signal corresponding to a fundamental frequency of the down-converted signal and rejects other frequencies to generate a band-passed signal. 17. The apparatus of claim 16, wherein the tracking filter further comprises a tunable low-pass filter and mean energy detector that low-pass filters the band-passed signal based on a control signal and generates a first mean energy output based on an output of the low-pass filter,a second mean energy detector that determines a second mean energy output based on the band-passed signal, anda controller that generates the control signal based on a difference between the first and second mean energy outputs. 18. The apparatus of claim 17, wherein the digital pulse generator comprises a second tunable filter that filters the band-passed signal based on the control signal, and a pulse generator that detects zero-crossings of the signal output by the second tunable filter and generates a pulse train signal based on the zero-crossings. 19. The apparatus of claim 17, wherein the digital pulse generator comprises in-phase and quadrature pulse generators,the in-phase pulse generator further comprises an in-phase tunable filter that filters an in-phase portion of the band-passed signal based on the control signal, andthe quadrature pulse generator further comprises a quadrature tunable filter that filters a quadrature portion of the band-passed signal based on the control signal. 20. The apparatus of claim 19, wherein the in-phase pulse generator further comprises an in-phase pulse generator that detects zero-crossings of the signal output by the in-phase tunable filter and generates an in-phase pulse train signal based on the in-phase zero-crossings, andthe quadrature pulse generator further comprises a quadrature pulse generator that detects zero-crossings of the signal output by the quadrature tunable filter and generates a quadrature pulse train signal based on the quadrature zero-crossings. 21. The apparatus of claim 20, wherein the in-phase/quadrature output selector outputs one of the in-phase pulse train signal and the quadrature pulse train signal as the output pulse train signal representative of the speed of the bladed rotor. 22. The apparatus of claim 20, wherein the in-phase/quadrature output selector is configured to select one of the selected in-phase pulse train signal and the selected quadrature pulse train signal for output as the output pulse train signal representative of the speed of the bladed rotor, andmaintain the selection of the one of the pulse train signals for output until a predetermined number of falling or rising edges occurs on another one of the pulse train signals while no falling or rising edges occur on the selected one of the pulse train signals. 23. A method for measuring an angular speed of a bladed rotor, comprising: radiating a microwave signal toward the bladed rotor;receiving a reflected microwave signal from the bladed rotor;down-converting the reflected microwave signal into a down-converted signal; andgenerating an output pulse train signal representative of the angular speed of the bladed rotor based on one of an in-phase portion or a quadrature portion of the down-converted signal, wherein generating the output pulse train signal further comprises:passing frequencies of the down-converted signal corresponding to a fundamental frequency of the down-converted signal and rejecting other frequencies to generate a band-passed signal; andfiltering the band-passed signal in response to a control signal to provide a filtered output. 24. The method of claim 23, further comprising producing a first mean energy output based on the filtered output; andproducing a second mean energy based on the band-passed signal. 25. The method of claim 24, further comprising generating the control signal based on a difference between the first and second mean energy outputs. 26. The method of claim 25, further comprising second filtering the band-passed signal in response to the control signal to provide a second filtered output. 27. The method of claim 26, further comprising detecting zero-crossings of the second filtered output; andgenerating the output pulse train signal based on the zero-crossings. 28. An apparatus for measuring a speed of a bladed rotor, comprising: a sensor that radiates a continuous-wave signal toward the bladed rotor and receives a reflected signal from the bladed rotor;a radio frequency module that generates the continuous-wave signal radiated by the sensor and down-converts the reflected signal into a down-converted signal; anda main processing module configured to generate an output pulse train signal representative of a speed of the bladed rotor based on one of an in-phase portion or a quadrature portion of the down-converted signal. 29. The apparatus of claim 28, wherein the main processing module comprises a bank of sub-band filters, a signal energy detector, a bank of sub-band energy detectors, and a sub-band selector, andthe signal energy detector detects a mean energy of the down-converted signal. 30. The apparatus of claim 29, wherein the bank of sub-band filters comprises a plurality of sub-band filters, andeach sub-band filter comprises a band-pass filter that provides a band-passed signal based on the down converted signal, a mean energy detector that detects a mean energy of the band-passed signal, and a zero-crossing detector that detects zero-crossings of the band-passed signal and generates a pulse train signal based on the zero-crossings of the band-passed signal. 31. The apparatus of claim 30, wherein the bank of sub-band energy detectors comprises a plurality of sub-band energy detectors, andeach sub-band energy detector comprises a comparator that compares the mean energy of a respective one of the band-passed signals to the mean energy of the down-converted signal and provides a sub-band selection signal. 32. The apparatus of claim 31, wherein the sub-band selector comprises selection logic and a sub-band selector,the selection logic generates control signals for the sub-band selector based on the sub-band selection signals from the sub-band energy detectors, andthe sub-band selector selects a pulse train signal among the pulse train signals generated from the sub-band filters for output as the output pulse train signal based on the control signals. 33. An apparatus for measuring a speed of a bladed rotor, comprising: a sensor that radiates a continuous-wave signal toward the bladed rotor and receives a reflected signal from the bladed rotor;a radio frequency module that generates the continuous-wave signal radiated by the sensor and down-converts the reflected signal into a down-converted signal; anda main processing module comprising a band-pass filter, a tracking filter, and a digital pulse generator, the main processing module being configured to generate an output pulse train signal representative of a speed of the bladed rotor based on the down-converted signal. 34. The apparatus of claim 33, wherein the band-pass filter passes frequencies of the down-converted signal corresponding to a fundamental frequency of the down-converted signal and rejects other frequencies to generate a band-passed signal. 35. The apparatus of claim 33, wherein the tracking filter further comprises a tunable low-pass filter and mean energy detector that low-pass filters the band-passed signal based on a control signal and generates a first mean energy output based on an output of the low-pass filter,a second mean energy detector that determines a second mean energy output based on the band-passed signal, anda controller that generates the control signal based on a difference between the first and second mean energy outputs. 36. The apparatus of claim 35, wherein the digital pulse generator comprises a second tunable filter that filters the band-passed signal based on the control signal, and a pulse generator that detects zero-crossings of the signal output by the second tunable filter and generates the output pulse train signal based on the zero-crossings.