13. The method of claim 12 , further comprising detecting, via the processing unit, S 1 and S 2 of at least 2 cardiac cycles for calculating an averaged cardiac cycle representation.
13. The method of claim 12 , further comprising detecting, via the processing unit, S 1 and S 2 of at least 2 cardiac cycles for calculating an averaged cardiac cycle representation. 14. The method of claim 13 , further comprising limiting, via the processing unit, influence of noise and other non-repetitive parasite artifacts and disturbances to the received signal.