Digital terrestrial television
Digital terrestrial television is a technology for terrestrial television where television stations broadcast television content in a digital format. DTTV is a major technological advance over analog television, and has largely replaced analog television broadcast, which had been in common use since the middle of the 20th century. Test broadcasts began in 1998 with the changeover to DTTV, also known as the Analog Switchoff (ASO) or Digital Switchover (DSO), which began in 2006 and is now complete in many countries. The advantages of digital terrestrial television are similar to those obtained by digitizing platforms such as cable TV, satellite, and telecommunications: more efficient use of radio spectrum bandwidth, provision of more television channels than analog, better quality images, and potentially lower operating costs for broadcasters.
DTT transmitters located at Mount Zhentou in Tainan, Taiwan
Two digital terrestrial television receiving antenna on the roof, upper antenna facing Tokyo Tower and lower one to another Local Television Stations in Kantō Plain of Japan until Tokyo Skytree operates. (For ISDB-T system)
Simple and low cost ISDB-T Set-top box (tuner) with remote control
Analog television shut down in Japan at noon. All television stations broadcast a blue information screen that displayed one or more telephone numbers for digital television inquiries on the day of the shutdown until the transmitters shut off at midnight.
Analog television is the original television technology that uses analog signals to transmit video and audio. In an analog television broadcast, the brightness, colors and sound are represented by amplitude, phase and frequency of an analog signal.
Early monochrome analog receiver with large dials for volume control and channel selection, and smaller ones for fine-tuning, brightness, contrast, and horizontal and vertical hold adjustments.
Analog television system by nation
Close up image of analog color screen
A waterfall display showing a 20 ms long interlaced PAL frame with high FFT resolution