Martha,
When you look at Randall's VI you will see that it processes more than a minute of data at a time. It takes about 180 ms to run on my computer, according to the Profiler. Much of that time is spent on the display, but the subVIs which do not show their front panels take about 44 ms. Smaller datasets can be processed faster, but you have to have enough data to determine which peak is which, meaning at least one beat and probably two or three minimum.
Some of those functions may available in a point-by-point version which would allow you to be responsive to current data. You can also create your own with shift registers.
You may be able to omit some functions if you do not need all of the analyses he does.
Filters have delays which are inversely proportional to their bandwidth. For batch processing this is not an issue. You will need to evaluate the delays in your application.
He finds peaks by looking at zero crossings of the derivative of the signal. Noisy signals will have spurious peaks. This is why he does the low pass filtering (with delays) ahead of the peak detection. Lots of trade-offs!
Lynn
