Using the Variance Calculation method, the software can detect the signal in the collection channel.

The ECG machine collects data through the adboard and writes the corresponding receiving information in the software. ProgramTo process, display, store, and process data. At this time, I encountered a problem because I collected data from 15 channels at the same time. When I collected the data, the user stared at the software and did not check the connection of the connecting line. If the connecting line fell off, users cannot find it in time. To detect lead shedding, there are two methods: hardware and software. The hardware method is very simple. Just test the input impedance of the guide line. Of course, the current hardware must support this function. The software method is relatively troublesome. For the software, only the continuously collected data is visible, and there is no way to know the status of the hardware layer such as the input group anti-attack. Therefore, you can only analyze the data. If the lead falls off, the input impedance will be infinitely large. The data transmitted by the ad version will either be a stagnant pool of stagnant water or a choppy wave (specifically, it is related to the adboard processing method and the electromagnetic interference in the field environment). In short, it is very different from normal ECG data. We take 150 pieces of data before and after the R wave detection, with a total of 300 points of data, that is, 0.3 seconds of data, and calculate the variance. If the variance is between 400-20 0000, it is considered to be a normal ECG signal. If it is less than 400 or greater than 20 0000, it must be lead loss. Of course, there is no rule for selecting this threshold value. It was done through a large number of experiments.