Adaptive sampling

摘要

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.

主权项

1. A method for adaptively sampling an analogue biopotential signal, the method comprising the steps of:
a) determining a derivative of the analogue biopotential signal; b) detecting a change in the derivative of the analogue biopotential signal; c) sampling the analogue biopotential signal using a sampling frequency; and d) using the change in the derivative of the analogue biopotential signal to control the sampling frequency of the analogue biopotential signal, wherein the process of controlling the sampling frequency of the analogue biopotential signal comprises comparing the change in the derivative of the analogue biopotential signal with an automatically controlled threshold value, and wherein the automatically controlled threshold value is generated from an expected average activity value and an extracted average activity value, the extracted average activity value being derived from the analogue biopotential signal, and the expected average activity value being derived from a beat frequency of the analogue biopotential signal.