High-definition television

High-definition television (HD or HDTV) describes a television system which provides a substantially higher than the previous generation of technologies. The term has been used since 1936; in more recent times, it refers to the generation following standard-definition television (SDTV), often abbreviated to HDTV or HD-TV. It is the current de facto standard video format used in most broadcasts: terrestrial broadcast television, cable television, satellite television and Blu-ray Discs. HDTV may be transmitted in various formats: 720p (): 921,600 pixels 1080i () interlaced scan: 1,036,800 pixels (≈1.04 Mpx). 1080p () progressive scan: 2,073,600 pixels (≈2.07 Mpx). Some countries also use a non-standard CTA resolution, such as : 777,600 pixels (≈0.78 Mpx) per field or 1,555,200 pixels (≈1.56 Mpx) per frame When transmitted at two megapixels per frame, HDTV provides about five times as many pixels as SD (standard-definition television). The increased resolution provides for a clearer, more detailed picture. In addition, progressive scan and higher frame rates result in a picture with less flicker and better rendering of fast motion. HDTV as is known today first started official broadcasting in 1989 in Japan, under the MUSE/Hi-Vision analog system. HDTV was widely adopted worldwide in the late 2000s. The term high definition once described a series of television systems originating from August 1936; however, these systems were only high definition when compared to earlier systems that were based on mechanical systems with as few as 30 lines of resolution. The ongoing competition between companies and nations to create true "HDTV" spanned the entire 20th century, as each new system became higher definition than the last. In the 2010s, this race has continued with 4K, 5K and 8K systems. The British high-definition TV service started trials in August 1936 and a regular service on 2 November 1936 using both the (mechanical) Baird 240 line sequential scan (later to be inaccurately rechristened 'progressive') and the (electronic) Marconi-EMI 405 line interlaced systems.

Metamaterial graphene photodetector with bandwidth exceeding 500 gigahertz

Yesim Koyaz, Michael Baumann

Although graphene has met many of its initially predicted optoelectronic, thermal, and mechanical properties, photodetectors with large spectral bandwidths and extremely high frequency responses remain outstanding. In this work, we demonstrate a >500 gigah ...

AMER ASSOC ADVANCEMENT SCIENCE2023

Climatic Affinities or Type As A Structure Of Relations, Based On Typological Transfer In The Work Of Lacaton & Vassal And Other Similar Precedents

Climatic Affinities or Type As A Structure Of Relations Based On Typological Transfer In The Work Of Lacaton & Vassal And Other Similar Precedents

Metamaterial graphene photodetector with bandwidth exceeding 500 gigahertz

Climatic Affinities or Type As A Structure Of Relations, Based On Typological Transfer In The Work Of Lacaton & Vassal And Other Similar Precedents