Variable Delay or Duty Cycle from an Array

[BryantD]

I currently have a 6602 counter/timer board. I am receiving an external signal to start my pulse generation. I need to generate three pulses 40 times at a certain frequency which is easily done by having two of them start off when the first starts, which is triggered off the external rising signal and prescribing the finite samples. However, I really need to have one signal that is delayed from the first by a set delay from an array that is different for all 40 times. It would also be beneficial to have a changing duty cycle. Any incite would be appreciated.    

[TaylorG]

Hi BryantD,

So if I read this correctly, you have 40 different "bursts" of 3 pulses, each of which is delayed from the previous by a random amount of time, and you want the duty cycle to be varying as well?  How do you want the duty cycle to change?

[BryantD]

I would like a 7Hz signal that repeats 40 times, with two pulses that are delayed from this signal with programmable delays that is different for every pulse on the order of 60 to 200 microseconds.  I have determined the ability to adjust the duty cycle is really not that important if I can change the delays.   

[John_P1]

Hi BryantD,

This isn't going to be possible using the 6602.  That board only allows for software-timed updates to the counter output, so you can't deterministically change the initial delay from pulse to pulse.

On the other hand, the newer X Series boards (e.g. PCIe 6320) should be capable of achieving your end-goal.   While I don't believe you can directly modify the initial delay for each pulse, you would be able to pre-build an array of high and low times to be output by the counter sequentially.  You could alternatively implement something similar using the clocked digital output lines (up to 1 MHz on the 632x and 634x, 10 MHz on the 635x and 636x).  If you prefer a solution in the PCI or PXI form-factor, then the slightly older M Series cards also support clocked digital tasks (but no buffered counter outputs).

Best Regards,