What is 4Kx2K, we said the transmission UHD is 3840 x 2160, 30HZ?

4K2K is an abbreviation for HD display resolution.
UHD: Short for Ultra High Loss
Representing the next generation of technology for "ultra-high clear", HD(High Deep HD), Full HD(full HD). The display with a physical resolution of 3840 × 2160(4K × 2K) and above is called ultra-clear, which is twice the width and height of ordinary FullHD(1920 X1080) and four times the area.
The 4K resolution refers to the horizontal direction where the pixel value reaches or approaches 4096, and in most cases it specifically refers to the 4096 * 2160 resolution. According to the range of use, 4K resolution also has a variety of derivative resolutions.
For example, Full Aperture 4K's 4096 * 3112, Academy 4K's 3656 * 2664, and UHDTV standard 3840 * 2160 all belong to the 4K resolution category.