Earlier I wrote: >If the scope has an X/Y mode, you can go beyond the usual >envelope pattern you get from putting RF on the X input... In my >professional work with AM, I find you can get a very useful pattern >by putting RF on the X input and line-level modulating audio on the Y. >It forms an ellipse that closes on 100% negative. I find it easier > to see the compression/limiting action as shades of intensity >on this waveform.
As I was driving home from the grocery store this afternoon, I realized that I suffered a brain-fade on this description. The above procedure gives you the trapezodial display, not the ellipse I was intending to describe. To get the ellipse, put RF from the transmitter on both the X and the Y inputs, preferrably with a fairly lengthy cable between the two so there is a bit of a phase difference, and you get the ellipse that closes the eye on 100% negative. Sorry for any confusion my error might have caused. And I wasn't drunk or anything... A mind is a terrible thing to waste... Steve WD8DAS
