Oscilloscope square wave problem

[evilteddy]

I just got an oscilloscope for my birthday from my parents today. Its an excellent present but I have been having one little niggling problem. When I attach the probe to the test/calibration square wave on the oscilloscope it will display the troughs and peaks of the square wave but not the rising and falling edges in between. I can just see a ghost of an edge when I'm zoomed in as far as I can be with the brightness on full. While it is a little niggling problem I would like to try and solve why its happening. So does anyone with oscilloscope experience have any suggestions?

[marshallh]

Nothing's wrong with your scope, they're all that way. I've used many from mid 70s to mid 90s and they all do it. The only ones showing the rising/falling edges are completely digital and use a line drawing algorithm to connect the sampling points.

[XCVG]

You got an OSCILLOSCOPE FOR YOUR BIRTHDAY?! You have very nice parents!

[evilteddy]

Thanks for putting my mind to rest on that Marshall. Obviously I don't really need to see the edges of a square wave but I was a bit worried that there might be some problem with the scope. I've already used it witha a PIC and an LCD and discovered the source of a problem on RA4 (I'd forgotten to tie it high).

XCVG: I'm very lucky!

Thanks again Marshall.

[nitro2k01]

If the edges are too rounded, you may need to calibrate you probe. Unless it's a cheap probe, it should have a little box with a small hole on the top. That hole goes to an adjustable capacitor that compensates for the capacitance in the probe wire. Use a small screwdriver to calibrate it so that the edge of the test signal is a sharp as possible.
Beware that if you're using a metal screwdriver, the screwdriver and your body affects the capacitance so you should lift the scredriver from the hole when inspecting the edge. Zoom in as you get closer to the perfect edge.