If CRO is Cathode Ray Oscilloscope and DSO is Digital Storage Oscilloscope then it is a function of the scope capabilities. Yes, there are scopes that do it using software made for them.
@ DerStrom8, please do me a favor and link to the other post? I replied to this one but never caught the other? I hate double posting as much as the next guy but when citing it a link to the other post is nice.