Hello and thank you for the posts.
I think it would be helpful here to briefly explain 12 bit resolution as this will help all when looking at low voltage measurements.
12 bit resolution allows for 4096 measurement levels or steps across the full voltage range. For example.
A voltage scale of +- 50 mV = 100 mV full voltage range (100 mV = 0.1 V)
Divide 0.1 V by 4096 gives us 0.000024 (24) microvolt measurement steps across the full voltage range.
This is more than ample to measure volt drop values sub 20 mV.Each of the vertical measurement steps/levels from the base of the screen to the top of the screen equates to 24 microvolts (24 microvolt vertical resolution on 100 mV range)
In the case of Robski’s square waveform, let’s assume we have a 12 V square wave, our voltage range will be +- 20 V. (40 V full voltage range)
40 divided by 4096 = 0.0097 (9.7) millivolt measurement steps across the full voltage range.
This will still reveal sub 20 mV, volt drop values but could now be getting challenging if we have excessive noise on the measurement signal.
Low pass filtering and scaling factors remains an option here to reveal the signal or voltage value of interest.
Please remember there will always be “noise” of some form on our signals and of course, some of these measurement steps will be consumed by noise.
Keep the number of samples on screen to a minimum of 1 MS as “detail is everything” when looking at such small signals.
1 MS is a good bench mark for a “one size fits all” sample control setting for all automotive signals. 2MS is better still for the ultimate horizontal resolution but be aware, files sizes will increase given the amount of detail we have captured on screen along with the number of waveforms in your buffer.
Assuming we have a 12 V square waveform we could always AC couple the signal removing the DC component of the signal.
This will reveal the AC component present on the signal and display the signal about the 0 V point on our scale.
Because the AC signal will generally be small, we can revert back to our +- 50 mV scale and take advantage of the 24 micro volt measurement steps.
Another option would be the resolution enhancement feature of PicoScope, where the best possible explanation can be found here at https://www.picotech.com/library/oscill ... nhancement
In effect we can increase the vertical resolution, (Measurement steps) in 0.5 bit increments.
For example if we jump to 14 bit resolution when looking at the 40 V full voltage range we then have
40 divided by 16384 = 0.0024 (2.4 mV) millivolt measurement steps across the full voltage range.
There is however a trade-off for this clever feature, improved vertical resolution comes at the expense of bandwidth/frequency response. (See the video in the link above)
I am not sure of the frequency of the square waveform under test, but once again with PicoScope we can use a combination of resolution enhancement, sample control/sample rate adjustment (to off-set the effects of reduced frequency response), filtering, scaling and maths to find exactly what we are looking for regardless of voltage level.
I hope this helps and if you can post a captured signal that would be great as we can see just how the application of the above features would help to obtain the volt drop values required.