Going from HDMI 1.4 to 2.1 there is a 5x increase is bandwidth. Is it because the cables themselves were never the issue but it was the connectors/chips in the devices themselves that couldn’t handle it?
I know part of it is the actual quality of the cables themselves and tighter tolerances, more twists in the wires, material purity, etc. but I can’t imagine that alone would be enough to fully account for this.
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There’s a lot going on here, and the explanations go way deeper than a 5 year old would understand. But, I’ll try to explain.
Computers work in 1s and 0s. They see electricity as either on or off. In order for the computer in your TV to understand what’s happening, it needs to have the signal in 1s and 0s.
Wires don’t work in 1s and 0s. Wires work in a (practically) continuous domain. They can be at 7 volts, 4 volts, 0 volts etc.
All data transmission standards have to solve this problem of turning a continuous space into a digital (discrete) space. How do we do that?
We build maps. A simple one would be to copy the same one we use in the computer. If there’s ANY electricity in the wire, read it as a 1. If there’s none, make a zero. (More accurately, computers say anything above x voltage is a 1, and anything below is a zero.)
That’s a pretty inefficient mapping, we can communicate a lot more information if we use more voltage levels. If we have a transmitter that has a maximum output of 10 volts, we can for example make 4 voltage levels. 0-2.5V is a 00, 2.51-5.00V is a 01, 5.01-7.50V is a 10, 7.5V+ is 11. By simply changing how we interpret the information on the wire, we just doubled how many bits we sent.
As the gaps between these levels get smaller and smaller, it gets harder and harder to delineate between the different levels. This is where key innovations have happened over the past 20 years. We have developed denser mappings, and have developed techniques that allow us to read those denser mappings. As a field, this is known as digital signal processing, and it has gotten orders of magnitude more advanced since the year 2000.
Understanding why reading these mappings is more challenging than a simple “look at the map” is best done with an electrical engineering degree. The short of it is, Electricity changes when it gets sent in wires, and those changes will muddy the waters. It can show up too late, too early, not at the correct level, all of which place limitations on how fast you can send data. We have gotten really good at predicting and designing around this fuzzy nature of electricity, and thus can send data much faster over the same medium.
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