ADAPTIVE SAMPLING
First Claim
1. A method of adaptively sampling a high frequency component of an analogue signal, the method comprising:
- a) determining a derivative of the analogue signal;
b) detecting a change in the derivative of the analogue signal;
c) sampling the analogue signal using a sampling frequency; and
d) controlling the sampling frequency of the analogue signal based at least in part on the change in the derivative of the analogue signal, the process of controlling the sampling frequency of the analogue signal comprises comparing the change in the derivative of the analogue signal with an automatically controlled threshold value.
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Accused Products
Abstract
A method and apparatus is disclosed for adaptively sampling an analogue signal to increase the sampling rate in the presence of high frequency content within the signal, for example, QRS complex of an ECG signal. In one aspect, a change in a derivative of the analogue signal is used to control a voltage-controlled oscillator to provide a clock signal for an analogue-to-digital converter. The change in the derivative is compared to an automatically controlled threshold value. The clock signal controls the sampling rate of the analogue-to-digital converter so that the sampling rate is increased from one level, where only P and T waves are present to another higher level when the QRS complex has been detected.
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Citations
20 Claims
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1. A method of adaptively sampling a high frequency component of an analogue signal, the method comprising:
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a) determining a derivative of the analogue signal; b) detecting a change in the derivative of the analogue signal; c) sampling the analogue signal using a sampling frequency; and d) controlling the sampling frequency of the analogue signal based at least in part on the change in the derivative of the analogue signal, the process of controlling the sampling frequency of the analogue signal comprises comparing the change in the derivative of the analogue signal with an automatically controlled threshold value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. An apparatus for adaptively sampling a high frequency component of an analogue signal, the apparatus comprising:
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a sampling device configured to sample the analogue signal at a sampling frequency; and a control device configured to control the sampling device, the control device comprising an activity detection device configured to detect a derivative of the analogue signal and to use a change in the derivative of the analogue signal to alter the sampling frequency of the sampling device, the activity detector comprising a comparator that compares the derivative of the analogue signal with an automatically controlled threshold value. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. A device for adaptively sampling a high frequency component of an analogue signal, the device comprising:
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means for determining a derivative of the analogue signal; means for detecting a change in the derivative of the analogue signal; means for sampling the analogue signal using a sampling frequency; and means for controlling the sampling frequency of the analogue signal based at least in part on the change in the derivative of the analogue signal, the process of controlling the sampling frequency of the analogue signal comprises comparing the change in the derivative of the analogue signal with an automatically controlled threshold value.
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Specification