Hi,I am not familiar with the PicoMite but what are you using to program things and how long does it take to respond to a falling edge being detected and it reading the ADC ?
If it were a 0V/3.3V square wave at 360 Hz you would have to read it within about 1.2 ms of falling edge to see it as a low. Longer than that and it will have gone high again.
If using a sine wave and there's a long delay, a rising ADC with increasing frequency is what I would expect to see.
Maybe pulse a GPIO so you can see when it's doing the read.
I'm also not clear about the input being 1.2V AC - The Pico isn't really tolerant to negative voltage.
A schematic or diagram of what you have may help in understanding things better.
Thanks for your reply. yes, you are right; I set a minimum "OFF SET" on the frequency generator; both the trigger and input signals are sine waves generated from the same frequency generator. I am currently using a LabView-based code for data collection. Could you please advise me regarding the source impedance (internal resistance) of the test signal? I aim for the signals measured by the 16 ADCs (across 4 PICO units, each with 4 ADC channels) to be below 0.8 V, as the trigger is set to the falling edge. At a lower frequency of 30 Hz, I observed voltages of 0.804 V and 0.811 V. However, as I increase the frequency, the voltage continues to rise, as detailed in the previously shared PDF file. My concern lies in understanding why this increase occurs, particularly because I plan to utilize this setup later for data acquisition from equipment where precision is paramount, and any deviation could compromise the results.
Statistics: Posted by hasham — Sat Aug 03, 2024 11:35 am