The NI Mask Trigger IP block provides the ability to compare point by point values of an indexed record against a mask, and give notification when the record exceeds the mask. This is useful in frequency domain triggering applications, where the output of an FFT is compared against a mask. This results in the ability to trigger off specific frequency bins. The FPGA block consists of a configurable LabVIEW FPGA Memory item configured in a way that it can compare a mask against multiple overlapping FFTs.