What could be causing this square wave distortion (pics inside)

[jahonen]

Originally posted by AndrewT
I was told a long time ago that a digital oscilloscope needed a sampling frequency about 10 times the required analogue bandwidth. Surely when working in reverse a similar ratio should apply. 44 kilosamples/second (ks/s) limits the bandwidth to about 4 to 5kHz.

I believe that rule with scopes was before the sinc-interpolation was used. With linear interpolation between samples, you need oversampling factor of something like that to display the waveform accurately. With sinc-interpolation, that can be relaxed considerably.

Regards,
Janne

[jneutron]

umm, guys?

The signal is reacting to the high slew rate before the transition has occured, as well as at the end of the transition.

That's tellin me that it's a digital thingy, exactly what eva said.

If it were simple overshoot after transition, that's a whole nuther ball of wax.

Cheers, John