I want to do simultaneous 180 degree out of phase continuous signal (square) at two analog outputs

[johngardner58]

Hello,

I would like to use a counter to trigger (internally) two analog outputs such that the continuous AC signal at each output is 180 degrees out of phase.

What I was hoping to do with no external connections besides the ao0 and ao1 was to use a counter timer as the trigger and have one analogOutput trigger on the rising edge and the other trigger on the falling edge to get the required result.

However it doesn't matter how I get there.   The one absolute requirement is that the two continuous AC signals are present at ao0 and ao1 outputs and that they are 180 degrees out of phase and that any triggering occurs on the PXI bus with not other external connections  the frequency is 25Hz.  My card is a PXIe-6363.

I was hoping to have the hardware do all the trigger work but if there is a software trigger approach that would

[CDancer]

Hi. I'm not familiar with the PXI cards but I assume analog output is similar to the PCI and USB DAQ cards. If that's the case the way I would do it is to do a 2-channel continuous analog output, using the ao clock as the clock source (default). Create two square wave waveforms with 180 degree phase difference and write them to the buffer.

The only possible problem I can see is that the analog outputs share the same DAC which is multiplexed so there might be a slight delay between the edges of the waveforms, but it will be on the order of microseconds.

[johngardner58 · Accepted solution]

Thanks,

That is what I ended up doing.   microseconds is plenty good enough.