It difficult tell based on the information that you have supplied.  The box isn't a DV3, that is the logo of Digital Video Broadcasting (the last character is a stylised upper case B) and to don't say when this fault occurs.
However assuming that it is a simple Freeview Receiver and the problem occurs when you are trying to watch a digital TV channel, it almost certainly your aerial causing it. 
Check the connections and alignment.
                
 T
                
 August 2009