In the frequency domain, time localization is destroyed (conversely, frequency content is unavailable in the time domain). If you want time localization you have to include a time domain analysis. Note that this includes "time-frequency" methods such as Windowed Fourier or Wavelet analysis.

R peak is a location in time domain. Just convert to time domain and use Pan-Thompkins algorithm to detect R peaks. Good luck.

sorry if I suggest here such my suggestion.

I am not here to outline you the importance of the HRV current studies and I have not to remember you that the current linear or non linear methodologies are not completely satisfactory. Of course every day we find papers published also in valuable international journals that continue to use standard linear indexes and FFT or DFT for their clinical investigations and conclusions. Non linear methodologies have their valuable content also if currently they still do not find a continuous clinical appreciation. Usually three bands are considered in the frequency domain , as you well know, the VLF, the LF , and the HF for short 5-6 minutes recording. We need to remain in this framework, we need to use such bands for our estimations but my modest opinion is that the basic methodology as well as the physiological setting need to be advanced. This is the reason because we have studied for several years a new method, called the CZF method. We have verified, however, that such method, although of great interest, results of difficult interpretation for some clinicians. Consequently we have elaborated a new method, the new CZF version , that , in addition to the rigour of the previous formulation , gives results that give immediate clinical interpretation.

The method as well the software for your experimentation are given in our site www.saistmp.com Consequently I invite all you to visit the site and go to use such new method in your experimental as well as clinical conditions and verify directly its interest. The present software is the primary elaboration. Within a brief time we will give the complete version responding to all the formulation of the method. All the researchers that , at this time, will result using currently such new CZF method will receive obviously automatically the updates.

A final question. We have experienced the method on a large number of subjects and in some different pathological conditions. Consequently don’t hesitate to contact me if you need help, suggestions, questions, previous results that may help you in your use of the method ([email protected])