Sunday, March 15, 2009

High-definition television

High-definition television (HDTV) is a digital television broadcasting system with higher resolution than traditional television systems (standard-definition TV, or SDTV). HDTV is digitally broadcast; the earliest implementations used analog broadcasting, but today digital television (DTV) signals are used, requiring less bandwidth due to digital video compression.

History of high-definition television

Further information: Analog high-definition television system
The term high definition once described a series of television systems originating from the late 1930s, starting with the British 240 line and 405 line black-and-white systems introduced in 1936, and including the American 525-line NTSC system established in 1941. However, these systems were only "high definition" when compared to earlier systems.

The British high definition TV service started trials in August 1936 and a regular service in November 1936 using both the Baird 240 line and Marconi-EMI 405 line systems. The Baird system was discontinued in February 1937.

A brief itemized history of early analog HD systems follows; these would be considered standard definition television systems today.

  • 1936: System-A, UK: 405 lines @ 50 Hz, discontinued 1986
  • 1938: Several countries used a 441 line system, France in 1956 being the last to discontinue it
  • 1939: System-M, USA: 525 lines @ 60 Hz
  • 1949: French (monochrome) 819 line @ 50 Hz system launched, discontinued 1983
  • 1952-1956: European adoption of 625 lines @ 50 Hz with PAL and SECAM color coming in 1967

All used interlacing and a 4:3 aspect ratio except the 405 line system which started as 5:4 and later changed to 4:3.

The post–WWII French 819-line black-and-white system was high definition in the contemporary sense, but was discontinued in 1983, before the final British 405-line broadcast. Experimental 405 line color transmissions were made in the 1950s using a modified NTSC system.

Since the formal adoption of DVB's widescreen HDTV transmission modes in the early 2000s the 525-line NTSC (and PAL-M) systems as well as the European 625-line PAL and SECAM systems are now regarded as standard definition television systems. In Australia, the 625-line digital progressive system (with 576 active lines) is officially recognized as high definition.

Panasonic Corporation

1006 Oaza Kadoma
Kadoma
Osaka, 571-8501
Japan - Map
Phone: 81 6 6908 1121
Fax: 81 6 6908 2351
Web Site: http://www.panasonic.net

Panasonic Corporation, through its subsidiaries, produces and sells electronic and electric products for consumer, business, and industrial uses. It operates through five segments: AVC Networks, Home Appliances, Components and Devices, MEW and PanaHome, and Other. AVC Networks segment offers LCD televisions, DVD recorders and players, SD memory cards, digital and video cameras, and audio equipment, as well as notebook PCs and ruggedized notebook PCs, PC peripherals, mobile phones, cordless telephones and facsimile equipment, network cameras and TV door intercom systems, automotive electronics and electronic toll collection terminals, and product tracking systems and payment terminals. Home Appliances segment offers washing machines, vacuum cleaners, dishwasher/dryers, rice cookers, microwave ovens, induction-heating cooking equipment, refrigerators, room air conditioners, water heating systems, and compressors, as well as healthcare systems, lighting, and environmental systems. Components and Devices segment provides semiconductors, electronic devices, batteries, and electric motors that are used primarily in AV equipment, information and communication devices, home appliances, and industrial equipments. MEW and PanaHome segment manufactures electrical construction materials, home appliances, building products, electronic and plastic materials, and automation controls, as well as engages in detached housing, home remodeling, and asset and property management businesses. Other segment engages in factory automation (FA) business. It offers various FA and other industrial equipment. This segment provides mounting processes and solutions from component insertion to wafer processing to develop circuit manufacturing technology. The company, formerly known as Matsushita Electric Industrial Co., Ltd., was founded in 1918 and is headquartered in Osaka, Japan.