After the analog signal is filtered and amplified, the appropriate amplitude and frequency band are obtained, and then it is converted into a digital signal through the A/D converter. When the signal frequency is not too high (such as less than 100Hz), if you want to observe the waveform of the digital signal after A/D in real time on the computer screen, you usually need to observe the signal waveforms of multiple channels at the same time. As time goes by, the waveform on the screen is constantly refreshed or scrolled over time. At the same time, dynamic or static text, graphics, or coordinate lines can be superimposed on the waveform. This is what the dynamic waveform display control is designed to accomplish. In medical signal acquisition and processing, it is often necessary to use real-time monitoring of multi-channel signal waveforms, such as bedside monitors, central monitoring, polysomnography, multi-lead electrocardiography and other equipment. This dynamic waveform display software component is indispensable. In fact, in addition to medical signals, dynamic waveform display components have application value in fields such as vibration and measurement and control.
The functions to be completed by the dynamic waveform control are: (1) Each time a set of channel data at this time is input, the displayed waveform is refreshed. The value range of the input data is between 0 and 1, which is the normalized value. , the frequency (or speed) of waveform refresh depends on the input data rate, that is, the number of input data per second. This speed can be controlled by a high-precision timer. (2) You can set which channels are visible and which channels are invisible. (3) You can set the display parameters of each channel waveform, such as the thickness and color of the curve, magnification, and baseline value. (4) The coordinate grid can be displayed, such as millimeter grid, and the coordinate grid usually does not change with time. (5) Dynamic text can be superimposed and displayed, that is, the displayed text content can change with time, such as heart rate value. (6) Static text can be superimposed and displayed, that is, the position of the text content does not change and is part of the background. (7) Dynamic graphics, such as small icons, can be superimposed and displayed, and the graphics can change over time and continuous animations can be displayed.
The dynamic waveform control has two working modes, scroll mode and refresh mode. The scrolling mode is that the waveform continuously scrolls from right to left on the screen, each time scrolling one horizontal pixel; the refresh mode is that there is a vertical refresh bar in the screen waveform, moving from left to right, each time moving one pixel, the left side of the refresh bar is the new waveform, and the right is the old waveform.
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