Test issue description:
Input -3V~3V square waveform. The output signal should be inverted 0~3V signal.
But i see big noise added on the output signal.
The noise frequency is about 70KHz, and it is independent with input signal frequency.
So what is the main reason?
Thanks in advance.
No microcontroller internal.
I put a 10uF cap between vcc and gnd, no effect with output noise.
If i put this cap between output and gnd, the noise vpp increase obviously.
Only Smith trigger, inverter and buffer between input and output.
Added after 28 minutes:
Good news. I have found the reasone.
Just like keith said, there is a internal clock which effect the output signal.