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一、心电信号在示波管上的显示我们知道,示波器利用示波管中电子束的静电偏转指示电位(电压)变化,因而心电信号经A/D采样、存贮处理、D/A转换后得到的电压输出,就可直接送到示波器上作记忆显示,它的电压变化直接反映了心电信号的幅值变化。基于上述设想,我们采用工程频率为4MHz的Z80作为CPU,用4K×8b作为内存。只要采样率为200Hz,就可记忆20s左右的心电信号信息。推移式的显示方式由软件完成,硬件在每两次采样(A/D)间隙(5ms)内完成一次扫描输出(D/A)。如果要在示波管的显示屏上显示5个周期的心电信号,则就要求D/A在5ms内转换1000个点(即200×5),其硬件框
First, the ECG signal on the oscilloscope display We know that the use of oscilloscope oscilloscope electron beam electrostatic deflection indicating potential (voltage) changes, and thus ECG signal by A / D sampling, storage processing, D / A Converted voltage output, you can directly sent to the oscilloscope for memory display, its voltage changes directly reflects the amplitude of the ECG signal changes. Based on the above assumptions, we use the project frequency of 4MHz Z80 as the CPU, with 4K × 8b as memory. As long as the sampling rate is 200Hz, you can remember about 20s ECG signal information. Push-through display mode is done by software, and the hardware performs one scan output (D / A) within each A / D gap (5ms). If you want to display the oscilloscope display of five cycles of ECG signals, it is required D / A conversion 1000 points in 5ms (ie 200 × 5), the hardware box