Calculating time difference between two signals

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RobynZ
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Calculating time difference between two signals

Post by RobynZ » Mon Nov 07, 2016 1:04 pm

Hello,

i want to measure the time between two signals.
The first signal (A) is a rectangle as an input into my measurement system.
The second signal (B) is the "reaction" of my measurement system at the output.
I want to measure the time delay between A & B.
Is there a better solution than doing it "by hand" with the time ruler?

Thanks a lot.

Martyn
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Re: Calculating time difference between two signals

Post by Martyn » Tue Nov 08, 2016 7:43 am

We currently do not have the ability to perform calculations and measurements between channels, although there is a feature request with the development team for this.
Martyn
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alexthehun
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Re: Calculating time difference between two signals

Post by alexthehun » Thu Jan 25, 2018 7:45 am

Is there an update on this issue? When is it going to be developed?
We use this kind of function on our cheap oscilloscopes and expected to see this simple feature on this PicoScopes too.
Thank you.

Martyn
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Re: Calculating time difference between two signals

Post by Martyn » Mon Jan 29, 2018 11:21 am

This has not been added as yet.

What specific functionality are you looking for ? Is it just the time between events on channels ?
Martyn
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ben@willcockses.com
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Re: Calculating time difference between two signals

Post by ben@willcockses.com » Sun Jun 17, 2018 8:16 am

I was also looking for the ability to measure the time from an edge on channel A to an edge on channel B, and was disappointed to find that such a basic feature was missing. More specifically, it's the ability to gather stats on the time that would be useful, for example to evaluate the jitter of a PLL. Picotech, I'd really urge you to add this feature to the software.

Martyn
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Re: Calculating time difference between two signals

Post by Martyn » Tue Jun 19, 2018 9:48 am

This is still on the new feature list, but hasn't made it into the development cycle yet. Recently the focus has been on the the introduction of the Deep Measure feature in 6.13, for cycle based measurements.

For measuring the jitter of a pll have you tried using persistence mode ?
Martyn
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johannes-stolz
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Re: Calculating time difference between two signals

Post by johannes-stolz » Sat Dec 08, 2018 3:54 pm

Dear Picoscope team,

I also recommend to have a user defined time measurement. It is not only useable for measuring turn-on and turn-off delay times on semiconductors, it can also be used for signal travelling on a simple line. I use it very often with the Picoscopes, also in lectures. Picoscope is my favourite tool in the labs - easy to use, almost intuitive. The manual time measurement with the rulers is a great tool, which gives great opportunity having it on an automated base.
All other functions (rise 20/80, rise 10/90, deep measure) can be derived from this.

On other scopes a rise time works similar to
(delay (0,8*A) - delay (0,2*A)) for a single pulse with positive polarity
For having the turn-on time of a semiconductor like on of the previous writers want is almost the same
(delay(0,1*B) - delay (0,5*A)), assuming a positive edge on both signals

The fact that you are already able to measure frequency, period, rise time, etc. leads to my assumption, that you have all in your hand.

Johannes

AndrewA
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Re: Calculating time difference between two signals

Post by AndrewA » Mon Dec 10, 2018 10:50 am

With DeepMeasure you can set this up to do 'time between two signals'-
-Set the trigger to Channel A
-Setup DeepMeasure on Channel B
The start and end times are referenced to the trigger on channel A.
By adjusting the trigger level and the threshold in the DeepMeasure you should be able to get measurement you want. This will be for the cycle number closest to the trigger point.
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lab!fyi
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Re: Calculating time difference between two signals

Post by lab!fyi » Mon Dec 10, 2018 4:19 pm

For signals with approx. same frequency, example on channels B, C - calculates unsigned difference:

B=1MHz, C=1.01MHz
graph(delta(B,C)) = duty((((atan(1/tan(pi*(B/10000)))/pi)+(B/10000))*-((atan(1/tan(pi*(C/10000)))/pi)+(C/10000))))*(1/200)*(1/freq(C))

B=1MHz, C=1MHz, 15° phase
delta(B,C) = ((((atan(1/tan(pi*(B/10000)))/pi)+(B/10000))*-((atan(1/tan(pi*(C/10000)))/pi)+(C/10000)))+0.25)*(1/freq(C))

It determines zero crossings & generates PWM, which can be post processed to get phase or delay (with help of freq(x)). duty(x) used for graphing does not like glitches (due to noise) so errors now and then. If need just delay better use delta(x,y) with PWM display.
Attachments
PS6_delay_measurement_graphed.jpg
PS6_delay_measurement.jpg
PS6_delta_RTS.jpg

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