Digital filter method for pulse wave extraction, and digital filter

Abstract

The present invention relates to the technical field of medical electronics, in which medical devices, such as electronic sphygmomanometers and blood oxygen monitors, need to extract and analyze human pulse signals, and particularly relates to a digital filter method and a digital filter that extract human pulse signals. The digital filter method can be applied to various digital medical devices. Provided in the scheme are a digital filter method and a digital filter, which provide a method that is simple and easy to implement and determination criteria for near-zero-hertz interference caused by a variety of interference sources, so that an extracted pulse wave spectrum is as clean as possible. The digital filter implemented by using the digital filter method can be used to separate a direct current component and an alternating current component from a signal output by a sensor, and extract a required pulse signal. The PCB circuit is simplified, interference and costs are reduced, and meanwhile the problem of a long delay in an analog filter is overcome. In the day of downsized high performance MCU chips, the digital filter method is especially applicable to mini wearable devices and is also applicable to general medical electronic devices.

Description

technical field [0001] The invention relates to the field of medical electronics technology in which medical equipment such as electronic sphygmomanometers and blood oxygen monitors need to extract and analyze human pulse signals, in particular to a digital filtering method and a digital filter for extracting human pulse signals, which can be applied to in a variety of digital medical devices. Background technique [0002] The present invention takes an electronic blood pressure measuring device based on the "oscillometric method" as an example to illustrate a digital filtering method and a digital filter that can be used to extract and analyze human pulse signals. The basic modules and system components of the electronic blood pressure measuring device are as follows: figure 1 As shown, the device can realize the automatic measurement of blood pressure. "Oscillometric method" is to obtain the static pressure signal generated by the artery through the pressure sensor durin...

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Problems solved by technology

[0004] 1. After determining the high-pass cutoff frequency of the filter, how to choose the appropriate circuit parameters is more troublesome, and the filter has a large delay, which will cause errors in the measurement results;

[0005] 2. Occupies a lot of PCB space, not suitable for wearable devices, and unreasonable wiring may introduce new interference;

[0006] 3. If a higher-order analog filter is used, the circuit will be larger, which will lead to an increase in hardware costs;

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