This setting is used most often for setting and checking video levels. The 1H display is similar to the 2H but obviously shows only one line of video per horizontal trace. These are used to make critical timing measurements in the area of sync pulses. These last two are also magnified modes, so they too may be positioned anywhere along the full line display. Filters Filters may be applied to any combination of the other switches except the CAL mode.
Filters limit the frequency from the input to the display.
There are three standard filters, flat, low pass and high pass. They have many names but here are the basics of how they work. Flat, is no filter, it passes the entire video signal. The second filter, Low Pass or IRE, is a filter that passes low frequency signals and slowly limits the amount of higher frequency signals. The final filter type is the High Pass or Chroma filter.