Teledyne LeCroy LabMaster 9Zi-A - Manual (Page 126)

LabMaster 9 Zi-A
118 922157-00 Rev A

Eye Diagram HBR (High Bit Rate) - same as Eye Diagram, but
optimized for high bit rate signals (bit rate > ~2/3 oscilloscope
bandwidth).

Flatness - Flat group delay compensation with a brick-wall frequency
response. While this provides the fastest rise time, there is also a
slight penalty of more preshoot and overshoot compared to Eye
Diagram mode. This selection is most often used in narrow-band
RF measurements where it is desired to maintain constant
magnitude response over the oscilloscope passband.

Flatness HBR (High Bit Rate) - same as Flatness, but optimized for
high bit rate signals (bit rate > ~2/3 oscilloscope bandwidth).