HC_CDC wrote:“Resolution enhancement is a technique for increasing the effective vertical resolution of the scope at the expense of high–frequency detail. Selecting resolution enhancement does not change the scope’s sampling rate or the amount of data available.”
I assume Steve can explain this better but here is my understanding of the topic.
Thank you for that challenge as every day I study here at Pico, and I too, like us all, are learning about such techniques and features. Whilst digging and delving into the pro and cons of Vertical Resolution I found this great short video on our PicoTV channel on YouTube https://www.youtube.com/watch?v=EUcUKz5DTcI and it is a must see. I don't know about you guys but whilst I study the theory, actually seeing the effects such as in the video, brings it all home.
One characteristic that comes from the enhancement feature is the trade off between vertical resolution and high frequency. I guess the same can be said for LowPass filtering as we know just how valuable the feature is when looking at Lambda etc. but also how much over filtering can disguise the signal beyond all recognition
HC_CDC wrote:Basically I sample at spec. resolution and then, when I look at static/saved data and the signal looks very dirty/noisy, I apply the enhancement by means of the probe selector (Channel Options Button) Often it helps to get a better idea of what’s happening using this adjustable filter and I find it very useful that it`s built-in. I find the Pico software incredibly good and I am sure I will find it better the more I discover what I can do with it, and I am not even talking about automotive.
Looking at the T and M software this would appear to be the means by which you have to filter using the 2204 scope as the LowPass filter feature is not available under the channel options button (Probe selector) as with the PicoScope 6 automotive software. There is however a work around with the T and M software using a custom maths channels (LowPass A, 10) giving you the best of both worlds using Vertical resolution and low pass feature for the desired amount of filtering.
Interesting point from Fat Freddy re
Fat Freddy wrote:Would the 8 and 10 bit resolution settings alter these captures? I have seen injector captures displayed incorrectly using incorrect settings?
This again is a point to note like over filtering, as it can disguise crucial areas of the waveform without careful analysis, which brings me onto
HC_CDC wrote:Quite often I look at the waveforms taken during a session a lot later and discover info that I had not even given a thought in the heat of trying to solve a problem quickly, this is how I found that you could apply the enhancement on an existing file.
With the pressures we are under to resolve complex running issues I have found capturing the data dirty with no input from either LowPass or vertical resolution is the best method. Once removed from the turmoil of the workshop environment there is so much work to be done with the analysis that does require a clear head. The process is however reversible and should you apply filtering and resolution enhancement during capture you can remove the features during analysis.
HC_CDC wrote:The 2204 is an 8 bit scope, 20V, Freddy. I think I could reduce the voltage range to say 0 to 60 to get more real resolution of the firing line, only not sure if the 200V plus peak (20 after the 10:1 probe really) would not fry the scope which than would be set to receive 0-4 volts. Steve??
We do have to tread very carefully with the T and M range of scopes when used in the automotive field, especially when it comes to the potential induced voltages with ignition primary. With our Cadillac the induced voltage does reach the 200 V point. via 10:1 attenuation is 20 V (Max input of your scope The overload however is 100 V). The scope 2204 is a pocket rocket for sure but it is vulnerable in this environment. 20:1 is better but still pushing the envelope with modern primary induced voltages at over 400 V. The amount of time the induced voltage is at a high level is very short but still places the scope at risk.
I hope this helps and please feedback when you can as I would love to see the waveforms after fix with increased attenuation.