An apparatus generates a pulse (or other hemodynamic) signal from an ECG signal, and displays a waveform of that signal. An ECG unit comprises electrode(s) for receiving an ECG signal waveform from live tissue and for generating a digital ECG signal； a memory storage； hardware processor(s) configured to constantly apply an integral function to the digital ECG signal and display a waveform of the integral function during a time period. The waveform of the integral function has a shape of a pulse signal waveform of the subject during the time period. The integral function comprisesPWF(t)T=A∫tt+TF(ECG(u))duECG(u) represents an ECG over a specific time period using a specific time resolution. T is determined from the ECG(u) time resolution and pulse frequency, T satisfies the Nyquist sampling theory, t, u are time variables and A is a positive constant. The memory stores the integral function waveform. A weight functionPWF(t)T=A∫tt+TF(ECG(u))·W(u−；t)dumay be included.
