FEATURE REQUEST: New Measurement 0-100 Rise/Fall

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namco
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Joined: Fri Aug 06, 2021 3:31 am

FEATURE REQUEST: New Measurement 0-100 Rise/Fall

Post by namco »

As the title says. I want to request a feature added to the software. Currently when selecting measurements for rise and fall time, you can only select 20-80 or 10-90. I would like for you all to update this so we can select custom selections on our own. So if we want, we can measure full 0-100 times or even say 5-95. Letting us pick the lower number and higher number. I know in many applications 10-90 is "good enough" but I am generally testing monitor pixel response. 10/90 for monitor pixel response is VERY misleading information due to how monitors work, meaning the only true measurement would be full 0-100 times. I am still a novice at using this software and I am just a hobbyist, but so far the only way to calculate full times if for me to point my mouse at the start and finish times, and then subtracting one from the other to find the full change over time. So if the dev team could, implement the ability to select the start and stop times for rise/fall in custom increments. Or just add the 0-100 time in! Thanks in Advance.

bennog
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Re: FEATURE REQUEST: New Measurement 0-100 Rise/Fall

Post by bennog »

0 - 100 % does not make any sense.
for example if the value only go's up to 99.99% then you will have no rise time.
Same for 0 if the capacitive value stays at 0.0001% then you never have a fall time.

Benno

namco
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Re: FEATURE REQUEST: New Measurement 0-100 Rise/Fall

Post by namco »

bennog wrote:
Sat Dec 04, 2021 4:40 pm
0 - 100 % does not make any sense.
for example if the value only go's up to 99.99% then you will have no rise time.
Same for 0 if the capacitive value stays at 0.0001% then you never have a fall time.

Benno
You have no clue what you are talking about. The whole point of rise and fall times is to measure how fast something changes in relation to time.

For example a monitor. Being measured with a photodiode which converts light to voltage and the oscilloscope reads that voltage. Lets say I go from 50mv to 100mv. The 10-90 TIME would start 10% of the low and stop at 90% of high, and give me a TIME of 5.6ms.... a 0-100 reading would start at 50mv and end at 100mv, giving me the full time it took from start to finish in terms of how long it took to change. In this example lets say thats 8ms.

For monitor testing, 10-90 times are misleading because monitor pixels will change even after the next hz in the refresh cycle is asked to display a new pixel.

Lets say you have a 4k resolution monitor with 144hz refresh rate. That is 144hz a second. To find how long it takes for 1hz to change, we use the math second/hz=milliseconds. So 1000/144=6.94ms. meaning each hz changes at a rate of 6.94ms. that monitor, in terms of pixel response, needs to change just as fast (6.94) or faster (5ms, 3ms, etc) in order to have a clear picture.

Lets say your 144hz monitor 10-90 time is 4ms, you would THINK that means the display is fast enough pixel wise to handle the 144hz. But in reality, the full 0-100 time is 15ms, which means the monitor is a dud.

A LOT of online monitor reviewers will measure in 10-90 because "industry set standard" but thats b/s. You have to know the full 0-100 times. Hardware Unboxed doesnt do 10-90 but they also dont do 0-100. They do something between which is still wrong.

When you have a panel with fast refresh but slow pixel, you induce ghosting and motion blur. The whole point of high refresh rate monitors is to reduce motion blur. But because pixel change times arent fast enough to keep up with how fast a panel changes in refresh rate. And pixels don't stop changing just because a new refresh says "change" again. Pixel changes dont "stop short". You can see thay with the blur busters teat where the screen is filled with squares and only 1 square should light up at a time. If more than 1 square lights up, the pixels are slower than the refresh.

I hope all this helps you understand better. 0-100 doesnt magically mean "if the signal doesn't reach blah blah you wont get a rise or fall time". The signal is always the same because in our case we measure light changes. Rise and fall times in this case is how long it takes for the light to change, or even stabilize. Even if my voltage is 1v to 10v and then next test 1v to 5v, 0-100 would still give me the TIME it took to change. The % 10-90 or 0-100 is just saying how long it takes to change in relation to data given.

Essentially what you said, makes no sense. And im surprised you are flagged as a power user and you dont even know how rise/fall times are measured.

Obli
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Re: FEATURE REQUEST: New Measurement 0-100 Rise/Fall

Post by Obli »

I absolutely second that. More options like 95%/5% or 99%/1% would be just great. Or maybe custom thresholds would be a good way to solve this.

santander
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Joined: Thu Oct 08, 2020 7:45 pm

Re: FEATURE REQUEST: New Measurement 0-100 Rise/Fall

Post by santander »

I came over this post as I need to measure the rise time from 30% to 90% of peak value. This is defined in IEC 60060 for front time measurement of 1.2/50 us impulse voltage so it would be great if the Picoscope coul measure this.

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