monitor wave
 

I have a Fedora core 3 installed in my TOSHIBA Portege R100 model notebook. Everything is OK including the Xserver. But when I scroll down the terminal menu or firefox homepage, there is wave problem in
the monitor. I wonder if it can be solved by modifying the monitor setting. Why did the phenomenon occur?

Thank you!

in my case such waves occur only when i have my cell phone placed near the monitor and somebody's calling me. it's a radio frequency interference in my case.;)