Hantek 4032L double-edges problem

KDE

Hi!

I've just purchased Hantek 4032L logic analyzer and have encountered the following problem: I connect a pure square wave 1 MHz generator to its inputs (to four of them for sure - A0, A1, A2 and B2) and instead of clean square wave I sometimes see double-edged waves:



So I've tried lowering the input square wave frequency to 1 KHz and sample rate down to 10 KS/s and stll sometimes see these "double edges", so it is definitely not a signal transition issue. I've tried connecting LA to another PCs using another USB cables - there is completely no difference, I always see these "double edges". I also have checked the input signal with oscilloscope in both cases (1 MHz and 1 KHz) and it is perfect - there are no any "double edges" or even transition spikes at all. So it is an LA issue.

What is this and how do I get rid of it?

Thank you.

amy

What is the voltage of the input signal?

KDE

The input signal has the standard CMOS levels - from 0 to 5 V. I've tried different LA's threshold settings with exactly the same result.

amy

Sir, that's normally.
Because the clock of the logic analyzer is not synchronized with the clock of the measured signal, it cannot guarantee that the acquisition point is completely correct.
It is recommended that you use an external clock, and then input the signal synchronized with the measured signal to the logic analyzer as the clock source.
Or when using the internal clock, set a higher sampling rate and then ignore a point on the edge.