no such a component

Nice to meet everyone see my problem here:

http://forum.niosforum.com/work2/style_emoticons/<#EMO_DIR#>/unsure.gif I need a A/D device to read the signal for my system,but I can&#39;t get it from the sopc component pool.And I am really sure there is not such a device.So in this case,am I need to creat my own peripheral(A/D convertor) using a tool.

Who can give me the way to realize such a device,which software need I to use.Is it the Quartus2 4.2 Megawizard plug-in Manager right??