Signal attenuator controllable by UDP,TCPIP?

[paul120]

Hello as part of a degree project I need to simulate digital television picture breakup, as demonstrated when the signal level is low or interferred with. I have found manual attenuators which are quite cheap but I need to automate the process with software on a pc. Is there anyway possible of acheiving this?
I envisage a pc running a usb tv receiever, the aerial coax cable plugged into a signal attenuator, the signal attenuantor having a serial input which allows the attenuation to be controlled via software on the PC. the software side is not an issue, merely the harware.
Many thanks

[wwtog]

Digital attenuators were common place when I was doing RF. May need to build a simple serial to parallel interface, maybe with a convertor to BCD. These should be available surplus, based upon the magnitudes of quanity that I have seen scrapped.