Method and apparatus for position and motion sensing
First Claim
1. An apparatus for separating information representing position from information representing activity in a digitized composite signal, said apparatus comprising:
- a first filter responsive to a first frequency range and configured to receive as an input said digitized composite signal;
a second filter responsive to a second frequency range and configured to receive as an input said digitized composite signal, said second frequency range being narrower than said first frequency range and comprising at least a part of said first frequency range, wherein an output of said second filter includes said information representing position; and
an adder for subtracting said output of said second filter from an output of said first filter, wherein an output of said adder includes said information representing activity.
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Abstract
An apparatus for extracting activity information and position information from a composite signal generated by a motion sensor includes an analog to digital converter for converting the composite signal from analog to digital format. A wide-band low pass filter having a frequency response of about zero hertz to about ten hertz and a narrow low pass filter having a frequency response of about zero hertz to about 0.5 hertz filter the digitized composite signal. An adder subtracts the output of the narrow-band low pass filter from the output of the wide-band low pass filter. The resulting difference represents information regarding the activity level of the motion sensor, and the output of the narrow-band low pass filter represents information regarding the position of the sensor.
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Citations
12 Claims
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1. An apparatus for separating information representing position from information representing activity in a digitized composite signal, said apparatus comprising:
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a first filter responsive to a first frequency range and configured to receive as an input said digitized composite signal;
a second filter responsive to a second frequency range and configured to receive as an input said digitized composite signal, said second frequency range being narrower than said first frequency range and comprising at least a part of said first frequency range, wherein an output of said second filter includes said information representing position; and
an adder for subtracting said output of said second filter from an output of said first filter, wherein an output of said adder includes said information representing activity. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
a rectifier configured to receive as an input said output of said adder; and
an integrator configured to receive as an input an output of said rectifier.
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7. The apparatus of claim 1 wherein said first frequency range is about zero hertz to about ten hertz, and said second frequency range is about zero hertz to about 0.5 hertz.
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8. The apparatus of claim 1 wherein said first frequency range is about zero hertz to about twenty hertz, and said second frequency range is about zero hertz to about one hertz.
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9. A method for separating information representing position from information representing activity in a digitized composite signal, said method comprising:
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low pass filtering said digitized composite signal to produce a first filtered signal, said low pass filtering passing a first frequency range;
narrow-band low pass filtering said digitized composite signal to produce a second filtered signal, said narrow-band low pass filtering passing a second frequency range, said second frequency range being narrower than said first frequency range and comprising at least a part of said first frequency range, wherein said second filtered signal includes said information representing position; and
subtracting said second filtered signal from said first filtered signal to produce a difference signal, wherein said difference signal includes information representing activity. - View Dependent Claims (10, 11, 12)
rectifying said difference signal to produce a rectified difference signal; and
integrating said rectified difference signal.
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11. The method of claim 9 wherein said first frequency range is about zero hertz to about ten hertz, and said second frequency range is about zero hertz to about 0.5 hertz.
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12. The method of claim 9 wherein said first frequency range is about zero hertz to about twenty hertz, and said second frequency range is about zero hertz to about one hertz.
Specification