How can I measure the frequencies of two analog input signals simultaneously?

[stove]

Hi

I have two AI signals, and I need to determine the frequencies of those signals. The frequencies range from 1-125Hz. I currently have a VI where I can sample one of the signals for 1 second (sampling at 300 Hz for 300 samples) and determine the frequency. 

I need to read two signals at the same time and get both of the frequencies at the same time, but I can only figure out how to read them individually, so I can read one signal, then one second later I read the second one, then I read the first one again, then the sceond one, etc..  How can I read two signals simultaneously?

Thanks

[Dennis_Knutson]

Just add the other channel to your physical channel list. When you click on the little arrow on the right side of the control, select browse and use CTrl-Click or Shift-Click to select multiple channels. If you want to manually enter a channel list, the syntax is Dev1/ai0:1 (for consecutive channels and Dev1/ai0,Dev1/ai2 for non-consecutive channels.

[andre.buurman@carya]

Don't forget to select multiple waveform acquisition.

[falkpl]

"at same time", this depends on the hardware, you can do as has been previously stated just set up a 2 channel acquisition and you will get 2 sampled waveforms back.  Most hardware A/D as multiplexed and true simultaneous sampling is not done.  At 125Hz this is not an issue unless you are interested in very small phase changes between the samples.  just keep this in mind if you are expecting samples to be completly synchronized.

Paul

[stove]

Thanks a lot for the help. This is exactly what I needed, didn't know it was that simple. 🙂