In an implicit buffered pulse measurement, on each edge of the Gate signal, the counter stores the count in the FIFO. The sampled values will be transferred to host memory using a high-speed data stream.
The counter begins counting when it is armed. The arm usually occurs between edges on the Gate input but the counting does not start until the desired edge. You can select whether to read the high pulse or low pulse first using the StartingEdge property in NI-DAQmx.
The figure below shows an example of an implicit buffered pulse measurement.