Hi Steve,
You are correct (photoelectric TXD) it is easy and convenient you
can just mount it on the ear or finger and after some signal conditioning
it is ready ,the amplitude of the signal is also very large as compared
to ECG signal and there fore it gives better S/N ratio however this
technique is severly subjected to motion artifacts.I have a BP meter
but according to which I have no right to live :) it most of the time
shows me 185(systolic) 140(diastolic) ie higher/lower BP. If you start
logging such a data what good will it do to you.where as conventional
instruments analog part with a long mercury column is damm accurate
(excluding subject's conditions).








sanjeev