Author Topic: Digital oscilloscope triggering and data collection question.  (Read 1152 times)

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Offline saint0r

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Recently I had to collect some data from a two way serial bus. Not going into specific details I had four signals,
clock (1MHz) and TX and RX sent with this clock and one big enable signal when the transaction occurs.

I have MSO 4104 (5 GS/s and 10M points buffer) and using logic probes I was able to trigger on enable signal.
I found out that when using my horizontal setting and getting actually 5 MS/s i was able to get  rather correctly clock and TX, RX (everything lower was getting rather bad results on pulse width of clock and data).

Problem here is that transaction takes about 5s and time acquired with this setting is less (2-3 s - can't rember exactly).
This means that I am not able to get and save whole TX,RX transaction.

Is it possible to somehow overcome this issue ? I wasn't able to figure out if it's possible to put a logic probe sample every 1 MHz clock cycle (trigger directly on the clock and save every sample to a buffer - can't really say if digital scopes can work like that - although it seems pretty simple).

Thanks in advance for any suggestions,

Offline ADT123

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Re: Digital oscilloscope triggering and data collection question.
« Reply #1 on: May 05, 2016, 04:35:56 am »
As your clock is 1MHz you will need to sample at about the 5MS/s you mention so for the 4 channels thats 20 million samples per second.  Over the 5 seconds you need 100 million samples.   Actually you need a bit more as you may find 500 millisec/div not quite enough and need 1sec/div.

Your scope does not have enough memory so you could use one of the streaming USB logic analyzers ( or if you need an analogue view of the data on a scope then Pico do some with >100M buffer memories (
Disclaimer:  I have worked for Pico Technology for over 25 years and designed some of their early oscilloscopes. 

Happy to answer Pico related questions when I have time but I am on eevblog in a personal capacity as electronics is a hobby.

Offline nctnico

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Re: Digital oscilloscope triggering and data collection question.
« Reply #2 on: May 05, 2016, 07:41:34 pm »
No segmented recording possible on the scope?
There are small lies, big lies and then there is what is on the screen of your oscilloscope.

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