ano bandwidth nung scope na gamit mo sis?
malapit na sa boundary ng most basic logic gates 'yung 30MHz. 'yung iba topped na at 25MHz ata.
Sir RD is right. LSTTL gates will have a hard time catching up with a 30MHz signal, as their rise and fall times will exceed the slope of a 30MHz signal. Looking at this in the frequency domain, the LSTTL inability to process >30MHz signal will make it behave like a low pass filter, suppressing the harmonics of the 30MHz squarewave. A square wave stripped off its harmonics is a sine wave. This effect is very similar to the slewing effect of an OPAMP, albeit occuring at a much lower frequency.
madyo malupit din ang overshoot at undershoot.
Welcome to the world of high speed electronics
. What you see are signal reflections caused by the stray reactance of your PCB traces, which acts essentially like a mismatched transmission line. This is the price you have to pay for owning a wide bandwidth oscilloscope, makikita mo na ang mga bagay bagay na magpapagulo sa isip mo.