For many users, WAVE's data analysis capabilities will be of greatest interest. WAVE itself does not perform analysis of the signals or annotations it displays. What WAVE offers is an easy-to-use means of controlling external analysis programs and viewing their outputs. The buttons in the Analyze window activate these external programs. These buttons are easy to create - in fact, you can add your own buttons to those in the Analyze window while WAVE is running.
In the previous chapter, we used the 
button to run the standard DB application program sqrs. In this
chapter, we will see how WAVE controls sqrs, and we will create
and test a new button to generate a heart rate signal using sqrs
and another standard DB application, tach. Discussions of
WAVE's ``logbook'' and ``oscilloscope'' facilities follow, and then
we study an extended example of how to develop an analysis program
controlled by WAVE, using the C programming language. At the end of
this chapter, we explore how this relationship can be inverted, so
that WAVE can be driven by an external program.
As before, use WAVE to open record 100s:
wave -r 100sClick right on
, click left on
Analyze..., and once again, click left on .
Where does the command that appears in the Analysis Commands window,
sqrs -r 100s -f 0 -t 1:00.000 -s 0come from, and what does it mean?
If you refer to the man page for sqrs, sqrs(1) (either by typing `man sqrs' in a terminal emulator window, or by looking it up in the ECG Database Applications Guide), you will see that the second command-line argument (100s) is (not surprisingly) the record name, `-f 0' instructs sqrs to start at the beginning of the record, `-t 1:00.000' tells it to stop 1 minute later, and `-s 0' specifies that signal 0 is to be used for QRS detection.