I am reading an input signal from an RC remote, which is a servo pulse, 1000-2000 uS in length. looking at it on my scope it sure SEEMs to be stable down to 4 uS (ie on my highest res, no jitter avail on the scope) however a lookk at the output yields a very periodic jitter, here is a screen cap of the plot, x axis is time, so the whole window is one second, and the y axis is pulse duration (using pulseIn()) in uS.
I tried putting a cap across the input, I tried a 10k resistor. Then i plotted the data and threw out my background noise jitter theory. My current ideas are
timing drift on the arduino clock
??
I don't know how to use a scope
2% error can be coded around, but I don't wanna accept something I don't have to. currently there is nothing else on the circuit that makes me think twice (no relays) about pwr supply noise. any one have any idea where I should be poking my nose around? any more info i can supply to help y'all guess at my issue?
sorry got distracted with all the other irons, not enough hands.
there is an attachment on my first post. it shows a small data set I collected with my arduino. this data set shows a very periodic variation in the pulse length. However my oscilloscope says this variation very definitely does not exist. I trust my scope more than the arduino, so I am trying to figure out what is giving me these results.
the x scale is seconds, meaning the time at which the pulse was captured, and the Y axis is pulse length, in uS.
Let me find the code I used, but I collected that data by sending pulsein() and millis() to the serial monitor, and copy pasta it into my spreadsheet software. will return with code.
