Recommendations for DAQ card for gated acquisition

[mwally12]

Hi everybody,

I am planning an experiment where I have to detect the first 1-2 us of a 10 us analog signal. I am looking into DAQ cards that enable me to gate the analog signal input and at the same time, have the best possible resolution, as my signal will be very small. Do you have any suggestions? the requirements are having analog input ports and a digital input or trigger input to gate the analog input channel. The analog input would be max 2 V.

I'd appreciate any possible suggestions.

Thanks!

-Mauricio

[santo_13]

Could you please elaborate on what you mean by "Gate" in your case?

If you want to capture analog signals at a high rate, sure, there are DAQs with AI at 2+MS/s which translates to a time resolution of 500ns.

[mwally12]

Hi Santhosh,

thanks for the quick reply. By "gate" I mean multiplying the analog signal with a gating signal that can only be high or low. When the gate signal is high, then the analog signal is valid and stored. When the gate signal is low, nothing is stored. In this way, the gate signal triggers the acquisiton of the analog signal.

The pulse width of my gating signal would be 1 us. So a sampling rate of 2 MS/s, would be 1 sample every 0.5 us, which wouldn't work for this case.

[Kevin_Price]

Under DAQmx, this would be known as a "Pause Trigger" which basically acts as an Enable/Disable control on a task.  Most common NI DAQ devices would support this.

It isn't clear to me why 2 MS/s "wouldn't work for this case".  Do you need a higher sample rate?  How high?  A high sample rate could push you into a different device class that uses a different driver, like NI-SCOPE for example.  But I'm afraid I don't have enough familiarity with such special purpose instrument-grade devices to offer much.

-Kevin P