I need to do the Frequency domain analysis on HRV. I have the input signal generated from the Simulate ECG source.vi from the Biomedical Toolkit. The VI samples at 500Hz evenly, so is interpolation needed? Then when i put the signal through FFT PSD, the y value output is weird on the PSD graph. Also i know that i need to split it into VLF LF and HF bands, which i need help also. Example block diagram most appreciated. Need to clarify urgently!! <a href="http://img174.imageshack.us/img174/3393/aaaoo5.jpg" target="_blank">Front panel</a> <a href="http://img510.imageshack.us/img510/5880/asboz6.jpg" target="_blank">Block diagram</a>