The advanced compatible television (ACTV) system is a proposal for the single-channel transmission of widescreen enhanced-definition television (EDTV) images. A widescreen high-definition source is encoded into a signal that is NTSC-compatible. Existing NTSC receivers display a selected 4:3 portion of the widescreen image with standard NTSC resolution. A new widescreen receiver is proposed, tuned to the same 6 MHz RF channel, that displays a widescreen image with a resolution in excess of 400 lines/picture height in both spatial dimensions. The encoding process is reviewed and the recovery of various signal components to produce the widescreen image in the ACTV receiver is discussed. >
This special issue of the proceedings of the IEEE presents a systematical and complete tutorial on digital television (DTV), produced by a team of DTV experts worldwide. This introductory paper puts the current DTV systems into perspective and explains the historical background and different evolution paths that each system took. The main focus is on terrestrial DTV systems, but satellite and cable DTV are also covered,as well as several other emerging services.
Purpose ::: The aim of this study was to characterize the patterns of recurrence in patients achieving pathologic complete response (pCR) after neoadjuvant chemoradiotherapy (CRT) for locally advanced rectal cancer.