Do you mean a digital descrambler? And what kind of digital signals are you trying to listen to.
If it's something like MDT or ASTRO or PROVOICE/AEGIS no...
but if you're talking about something like POCSAG or GOLAY or RTTY and PACKET yes...
most people here are going to assume you're refering to digital trunking, the answer is NO. you'll have to buy a digital capable trunking scanner. And only if it's motorola. If it's EDACS forget it.