ENHANCED DEFINITION (ED)
Enhanced Definition (ED) is a term used in CRT (Cathode Ray Tube) technology to describe a video resolution that falls between standard definition (SD) and high definition (HD). It represents an improvement in image quality and detail compared to traditional SD resolutions.
In CRT technology, enhanced definition typically refers to the 480p (progressive scan) resolution, also known as EDTV (Enhanced Definition Television). Unlike interlaced SD resolutions, which display alternating lines in each frame, 480p progressively scans and displays all 480 lines in a single frame. This results in a smoother and more detailed image with reduced motion artifacts.
The 480p resolution typically offers several advantages over standard interlaced SD resolutions, including improved clarity, sharper edges, and enhanced detail in both still images and moving content. It is particularly noticeable in scenes with fast motion, as it minimizes the blurring and jagged edges associated with interlacing.
Enhanced Definition became popular in the late 1990s and early 2000s as a transitional step between traditional SD and the emerging HD resolutions. It provided a noticeable upgrade in picture quality without requiring the significant bandwidth and equipment upgrades needed for full HD.