Ipod interference through a dock
 

I just bought an alarm clock/ipod dock and I noticed whenever I connect the ipod, even when it's not playing anything, when the light goes out I get whistling and interference, I've noticed this on my car dock as well only when the backlight on the ipod goes out do I get the interference, is there any cure for this, does anyone have a similar problem, it's an iPod Video.

Cheers