As the title, I am willing to program in C language to use a sound card
as a data acquisition system with the function of pretrigger, as used
in Matlab.

I have been searching on the internet for long time, but no useful
information. There are some shareware of soft ocsiscope.

Any idea? Thank you very much.

Ze Ji wrote:
> As the title, I am willing to program in C language to use a sound card
> as a data acquisition system with the function of pretrigger, as used
> in Matlab.
> 
> I have been searching on the internet for long time, but no useful
> information. There are some shareware of soft ocsiscope.
> 
> Any idea? Thank you very much.
> 

You might want to try:

http://www.google.com/search?q=%22software+oscilloscope%22+shareware+windows 
16500 hits
http://www.google.com/search?q=%22software+oscilloscope%22+shareware+linux 
     390 hits

http://www.google.com/search?q=%22software+oscilloscope%22+freeware+windows 
  11900 hits
http://www.google.com/search?q=%22software+oscilloscope%22+freeware+linux 
      430 hits

http://www.google.com/search?q=%22software+oscilloscope%22+%22C+language%22
54 hits