To summarize my problem, I'm trying to create a period and voltage controlled sequence of pulses , but as I decrease my duty cycle, the distance between each pulse starts to become irregular. Specifically:
I want to have three pulses, each of a specified positive amplitude, 80 microseconds long, with 23 ms in between each. After those three pulses, I'd like to have a negative pulse of 3* that amplitude, followed again by 23 ms. This cycle should repeat 260 times.
I tried to first create the positive pulses by using the Simulate Signal VI, setting it to a square wave with a frequency of 43.327556, an offset of 0.5 and amplitude of 0.5. With the duty cycle as the default 50%, the signal seems to be normal (constant frequency and duration of each pulse is equal; I'm measuring it using an oscilloscope). However, when setting the duty cycle to .3466%, the times between each pulse varies and some pulses are longer than others. I wrote the data to a measurement file directly from the Simulate Signal VI to make sure it wasn't just an oscilloscope problem, but it looked like the write to measurement file didn't sample enough points for me to measure this accurately. Even decreasing the duty cycle to just 10%, I see the issue arise already.
So my question is, am I doing something wrong here? Is there some kind of Labview lag with trying to do a duty cycle that small? And are there any alternatives to the way I have this set up? I was thinking about trying to use a pulse train instead, but I'm not very familiar with that and as far as I know, you can't control the amplitude of pulses.
Any help is appreciated! Thank you very much.