Show us your square wave

[norbert.kiszka]

74LVC14AD from Texas Instruments and modified Rigol DHO924S (removed 250 MHz low pass filter on channels 3 and 4).

Sadly this scope has a sinc interpolation that can't be disabled (until I hack this someday). It goes up to 450 MHz and ~600 ps rise time (800 ps per sample), according to this scope.

[jundar]

74LVC14AD from Texas Instruments...

Does this exact "device" in the first photo generate <nS rise time signal? Could you please share the schematic of it? Thank you.

[norbert.kiszka]

74LVC14AD from Texas Instruments...

Does this exact "device" in the first photo generate <nS rise time signal? Could you please share the schematic of it? Thank you.

If You zoom in first photo, You will probably see that I just shorted 3 (three) pins together - 11, 10 and 9. So one of gates became a ~450 MHz generator connected to input of other gate, output of this second gate (pin 8) is soldered directly into very small BNC female socket - I used "sex adapter" to connect it into scope. Pin 7 is GND and distance between 7 and 8 is good enough to solder both of them into mentioned BNC. Also THT 1uF ceramic capacitor (100 nF is not enough to make that fast rise time). That of course will make something more like sinus than square wave.

After that, I removed this wire (3 pins) and connected external generator (DIY on a separate PCB) ~17 MHz via short as possible wires (both power and signal) into pin 9. Used scope has 1.25 GS/s so there is 800 ps between samples - very likely real rise time was much lower than 800 ps (I guess 600 ps or maybe even faster).

[PartialDischarge]

74LVC14AD from Texas Instruments...

Does this exact "device" in the first photo generate <nS rise time signal? Could you please share the schematic of it? Thank you.

Read this https://www.eevblog.com/forum/testgear/show-us-your-square-wave/msg4510763/#msg4510763