A digital signal can have more than two levels. In this case, we can send more than 1 bit for each level. Each signal level is represented by 3 bits. A digital signal has nine levels.

A true square wave has a vertical line for its face. That is, an increase from Vmin to Vmax in zero seconds. Anything (except zero) divided by zero is infinity. In reality it takes time for the voltage to rise from Vmin to Vmax, and so there is a finite limit to the bandwidth.

2 bits

In general 2n levels require n bits. In the case of 256-level voice quantization, where each level is represented by a sequence of 8 bits, the overall rate of transmission is 8,000 samples per second times 8 bits per sample, or 64,000 bits per second. All 8 bits must be transmitted before the next sample appears.

The wavelength is the distance a simple signal can travel in one period. In a coaxial or fiber-optic cable, however, the wavelength is shorter (0.5 µm) because the propagation speed in the cable is decreased. So far, we have focused on simple sine waves. Simple sine waves have many applications in daily life.

In theory, though, HDMI 2.0 (effectively HDMI 2.0b since late 2016) can do 4K 120Hz. At most you’ll be able to get 120Hz in 1440p with some televisions and monitors, though you’re more likely to be limited to 120Hz in 1080p, even if you have a very fast 2K display.

HDMI 2.0 is also fairly standard and can be used for 240Hz at 1080p, 144Hz at 1440p and 60Hz at 4K.

With HDMI 1.4 you’re limited to a frame rate of 24fps when watching 4K video. Because of its higher bandwidth and ability to transfer more data per second, HDMI 2.0 can support 4K video at up to 60 frames per second — optimal for watching live sports or playing video games.