eli5: What is bandwidth?
In: 48
Bandwidth has two meanings.
For most things, bandwidth is how many boxes you can move at the same time. You can carry 3 boxes, but a moving truck can carry 50 at once. So the moving truck has more bandwidth. This meaning is also called “throughput”.
Wireless signals like wifi or radio use a different meaning.
Wireless signals need to be strong. So you usually send the message as loud as you can. So to make sounds that sound like language, you need a new way to send them. “Frequency Modulation” is that language, and it’s spoken by talking faster or slower. Bandwidth in wireless is usually the space between the fastest and slowest you can speak.
Other wireless signals use “Amplitude Modulation” where you speak louder or quieter to say a message. It is easier to make things with this language instead, but they are sometimes hard to hear. Bandwidth for these signals is the space between the loudest and quietest you can speak. So bandwidth for signals is *roughly* like how many letters there are in the alphabet.
Measurement of all members standing shoulder to shoulder.
Green Day = smaller band width
Tower of Power = larger band width
God a lot of these explanations are terrible.
Radio signals are typically described as having a particularly frequency, but historically when it was necessary to communicate more information at once multiple related signals were sent at once. A range of frequencies was designated as being used for a sequence of related signals. Depicted on an axis showing all possibly frequencies, the range was depicted as a stroke on this graph, covering all frequencies in use. The result was a “band” the width of which indicated how many frequencies were in use. Hence Bandwidth.
Because sending multiple signals was used to achieve faster speeds in mediums like radio, when more advanced signaling methods were invented the term bandwidth was borrowed to generally refer to the the amount of information simultaneously crammed into a single signal.
Because the determining factor in data transfer rates is often signal density (though not the only one) and bandwidth had also become synonymous with data speeds.
Notably, there are all kinds of ways to increase the information density of a given signal, such as insulating the medium to reduce interference, removing error correction, increase the cycling speed of the signa etc etc. However, all of these techniques that don’t increase the “width” of the involved frequency band are collectively referred to as “increasing bandwidth”
When you look at a rainbow and pick out colors you can look at a tiny sliver of yellow or a big patch of orange stretching from red to yellow. The “width” of that “band” is the bandwitth. Because more types of colors are in it you can signal more information. With a tiny slice you can only signal dark or light, but with more color you can add a little more red or a little more blue or darker or lighter. The amount of information you can send is determined by if you can tell the difference between them.
Lets imagine you are a kid again and a playing flashlight telephone with your friend Dave. You both had flashlight strong enough to be seen from each other’s house and you both flash each other messages by turning your flashlights on and off in specific patterns that represent letters and puncutation. It’s a fairly basic but functional messaging system, but there is a problem: when you have a big message to send, you flash your light as fast as you can, but David isn’t fast enough to transcribe your signals correctly. With some experimentation you and David figure out exactly how fast you can flash your lights before the messages get scrambled. In doing so, you have basically discover what Bandwidth is.
Bandwidth is a measurement of how fast you can change the data in a signal without loosing data in it. Depending on which transmission method you use, you either encode the data as changes in amplitude (AM signals) and the bandwidth tells you how short each data element can be, or the data is encoded as a component of which frequencies are in the signal (FM) and the bandwidth limits how many data bits can be encoded at once. Either way, the higher the bandwidth, the more data you can send at once.
Bandwidth is the width (range) of the band (frequency) of the signal (electromagnetic radiation, such as radio waves or light) that can be propogated through a medium. But in contemporary terms, it means *data rate*, how many bits can be processed by a system. The relationship between the term and its usage is straightforward, but detailed.
Basically, the higher the frequency of the waves, the faster they can switch from a binary 1 to a binary 0, so the more data you can send in a given time period. So the wider the bandwidth, the higher the frequency you can use, so the more data you can send.
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