Keithley DMM7510 Reference Manual page 249

Section 3: Functions and features Model DMM7510 7½ Digit Graphical Sampling Multimeter Reference Manual
Window mode
Window triggers occur when a signal enters or leaves a defined signal window.
When you set up window mode, you define the high and low analog trigger levels. You also define
whether the trigger should occur when the signal enters or leaves the window.
Figure 131: Window analog trigger mode
High frequency rejection
You can enable high frequency rejection for any analog trigger mode. False triggering around the set
analog trigger level may occur with low frequency signals that are noisy, DC, or have low amplitude
and slew rate during the peaks of input sine waves less than 250 Hz. High frequency rejection avoids
the false triggers by the requiring the trigger event to be sustained for at least 64 μs. This behavior is
similar to a low pass filter effect with a 4 kHz 3 dB bandwidth.
When high frequency rejection is on, 64 μs of additional trigger latency is incurred. You may also
need to adjust the trigger levels to ensure that the trigger condition is satisfied for at least 64 μs.
3-66 DMM7510-901-01 Rev. B / May 2015