Reply by mnentwig December 3, 20072007-12-03
Depending on the requirements, a soundcard may even be enough.
Some example code for full-duplex audio on my web page:
 http://www.elisanet.fi/mnentwig/webroot/looprecord/index.html

Most sound cards are AC coupled, so it won't work with frequencies < 20 Hz
or so.
If you need better equipment, yes, there is a variety of cards on the
market. It depends on how much you are willing to spend.

As a programmable generator, for example Rohde&Schwarz AMIQ comes to mind.
But it really depends on the requirements.
Reply by johnstokes December 2, 20072007-12-02
hi
understand it is possible to get software programs for your pc
that will allow you input sinewaves into board and then take analogue
output from board back into pc for evaluation?