Last Acq Histogram

C/C++ Equivalent: NISCOPE_VAL_LAST_ACQ_HISTOGRAM

The initial x value returned is the bin value for the first bin, corresponding to the midpoint of the range of values in the first bin. The x increment returned is the bin size. The last acquisition histogram method is used by the voltage low and voltage high measurements for computing the extrema of a waveform. This method is useful for ignoring overshoot or preshoot in a square waveform.

In the last acquisition histogram method, a voltage histogram is created from the most recent acquisition. The limits of the histogram are set by the minimum and maximum voltages of the acquisition. NI-SCOPE then counts how many samples fall into each bin of the histogram. The resolution is defined by the Last Acquisition Histogram Size attribute, which is 256 bins by default. You can fetch the histogram array using the Fetch Array Measurement function, with Last Acquisition Histogram constant specified as the array measurement function. The following illustrations show an example of a square wave and its resulting histogram. The voltage low and voltage high measurements correspond to the middle value of a bin with the maximum number of hits in the lower 40% or upper 40%, respectively.