I'm afraid a simple time-domain function can't describe the morbid graphics correctly (or summarize all kinds of morbid graphics).

You can try to use the frequency domain graphics function. Using fast Fourier transform, it is easy to transform from time domain to frequency domain and from frequency domain to time domain.

Check the information about the diagnosis and research of pulse function.

For example:

Mathematical analysis method of pulse condition in traditional Chinese medicine, China Journal of Modern Chinese and Western Medicine, Volume 2,No. 10, June 2004.