How can i perform scans at rising and trailing edges of an ext clk?

Question

I'm using a PCI 6024 DAQ card which can scan analog channels only at either the rising edge or the trailing edge pf an ext scan clk.but my application needs scanning to be performed at both the edges.can anyone plz help me??

Answer 1

If you can add some simple hardware to your setup, look at using a clock doubler so you can get two rising edges in the one clock period of the original clock. The doubled clock will only be used as a trigger for the DAQ card. Search Google for ["clock doubler" circuit] (include the double quotes, not the brackets). Click here or here for some sample circuits. The doubled clock will be out of phase with the original clock by the propagation delays of the gates in the circuits. If you're sampling in the kHz range or lower, the propagation delays won't affect your measurements.