Second order correlation: Accumulate the digital pulses with respect a trigger

[Lidia]

Hello everyone, 

I have the analog discovery pro 5250 and I am trying to correlate two digital channels (DIN0 and DIN1) one respect to the other. I want DNO0 to be the trigger and to measure the temporal delay of the pulses in DIN1 respect to that trigger. Then I want to accumulate the delays measured in a histogram, so I can get the second order correlation function of the signal. I am trying to use the Logic Analyzer directly so I can have the measurement faster and in real time, so I could see the histogram forming itself when I run WaveForms. 

I am learning to use the device and I have no idea if this is possible.

The final result should be some sort of histogram with the pulses in DIN1 accumulated, showing how mane pulses are detected in a certain delay time respect to the trigger DIN0.

[JColvin]

Hi @Lidia,

I have some clarification questions to help make sure that I understand your setup correctly.

1. You have two external signals that are being fed into the Analog Discovery Pro device.
2. Are these two signals correlated with each other? Or more specifically, when the signal connected to DIN 0 becomes active, it is expected that the signal on DIN 1 will become active within a certain timeframe?
   1. I am asking because in your screenshot there appears to be a situation where there is a rising edge on DIN 0, but no corresponding change on DIN 1 before the next rising edge of DIO 0.
   2. This leaves an open-ended question of if the second DIN 1 rising edge that is visible in your screenshot is the result of (or should be measured against) the first DIO 0 rising edge in the center of your capture or the second rising edge. Either situation will cause problems in the delay calculation.

I might be wrong, but I don't think there is a histogram view built into the Logic Analyzer for timing purposes. What I would probably be trying to do would be to use the Events view (timestamp and what change was detected on a channel) to capture when the changes on the data lines occur and then either Export or use the Logging option to get the events into a local file on your computer for analysis.

Thanks,
JColvin

[Lidia]

Hello @JColvin, thanks for the soon reply.

1. Yes, I have two external digital signals connected to the device. 

2. Both of the signals come from the same source. To be precise, I have a source which signal is divided in two (reducing the intensity to half for each of them). I want to correlate them in order to obtain the period of the source and to demonstrate that the source signal has a certain behaviour. The way to do so is to measure the time delay between the pulses in DIN0 and the pulses in DIN1. So basically I want the accumulative average of the pulses time in DIN1 respect to the central pulse given by DIN0 (trigger). 

The idea is to make an acquisition for a certain time and accumulate how many times a certain delay has been measured. Supposedly, I have been told than the oscilloscope can do that as an accumulative average, but I cannot find in the manual how to do it.