On Sat, 22 Oct 2005 21:57:43 -0700, matt weber
wrote:

On Sat, 22 Oct 2005 19:46:51 -0400, "E.F." wrote:

What are some of the interferences out there that mess up SW?? It seems
that everytime I have my laptop on it get a high pitch tone.

EF

The inverter that powers the backlight on the display is the likely
culprit. It is kind of like the Horizontal output on a TV, nice saw
tooth wave with harmonics that reach well into the HF spectrum.

Just about every other clock inside the computer runs at frequencies
well above HF.
The vertical waveform in the TV is the one that causes all the
buzzing.