Which term describes the display that forms a complete frame by two vertical scans?

Which term describes the display that forms a complete frame by two vertical scans?

• A. A-scan
• B. Plan Position Indicator (PPI)
• C. C-scan
• D. Raster (correct)

Answer: (D)

A raster display is created by two scanning motions working together to fill the screen: a fast horizontal sweep draws each line from left to right, while a slower vertical sweep moves down to the next line. When these two perpendicular scans repeat across all lines, the entire rectangular frame is formed. This grid-like image is what we call a raster display. A-scan shows a single vertical trace of amplitude versus time, not a full frame; PPI is a circular plan-view presentation, and C-scan is another type of plan-view display.

A raster display is created by two scanning motions working together to fill the screen: a fast horizontal sweep draws each line from left to right, while a slower vertical sweep moves down to the next line. When these two perpendicular scans repeat across all lines, the entire rectangular frame is formed. This grid-like image is what we call a raster display. A-scan shows a single vertical trace of amplitude versus time, not a full frame; PPI is a circular plan-view presentation, and C-scan is another type of plan-view display.