A new television standard called Ultra HD is four times sharper than today's best HDTVs.
比今日最好的高清电视还要清晰4倍的超高清电视标准已经出现。
英语百科
Broadcast television systems
Broadcast television systems are encoding or formatting standards for the transmission and reception of terrestrial television signals. There were three main analog television systems in use around the world until late 2010s (expected): NTSC, PAL, and SECAM. Now in digital television (DTV), there are four main systems in use around the world: ATSC, DVB, ISDB and DTMB.