What is the difference of a radio wave than a sine wave?
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A sine wave is really a mathematical object, it’s a waveform that oscillates up and down at a constant frequency defined by the equation y = sin(x).
Radio waves are an oscillation of electric and magnetic fields, as such they can be close to pure sine waves or they can have much more complex wave forms. Any real wave is always going to be slightly different from a pure sine wave at the very least because it has a start and end where as a pure sine wave is infinite in length.
Well the difference is like a drawing of a house versus an actual house.
A sine wave is a mathematical construct. It is useful because it is easy to work with mathematically speaking and it can be used to model and represent real life phenomena, like radio waves.
A radio wave is a disturbance or vibration in the electromagnetic field. It is “real” – it can be measured and analyzed. It has effects on physical objects – electromagnetic waves are used in microwave ovens to heat food, it is used for communication. All light is a form of electromagnetic waves. The term radio wave is simply a subset of electromagnetic wave frequencies that humans have given a name to (nature doesn’t care)
In order for humans to understand and use radio waves, there needs to be a way to represent them and ways to predict what happens. The best way appears to be through mathematics and using sine waves as a building block of our understanding.
Think of it like a single musical note compared with a piece of music. A pure musical note can be represented as a sine wave – a curve which repeats with a certain frequency. But piece of music is the sum of lots of different notes of different frequencies and so it becomes a complex non-repeating curve.
Similarly a radio signal can be a single repeating “note”, but is more often the sum of lots and lots of different “notes” so forms a non-repeating pattern.
When you stick up an antenna and run an oscillating current through it, you’re going to produce a sine wave, the building block of all radio communication. How fast that sine wave repeats is what determines your frequency.
Now, that sine wave itself doesn’t carry any information. It’s just a sine wave. So to send information with it the wave must be altered in some fashion that makes sense to the guy on the other end. You can modify the frequency of the sine wave, the amplitude of the sine wave, or the phase of the sine wave (i.e., where it is in its oscillation cycle), or even a combination of amplitude and phase. This is why a radio wave that carries information is no longer a perfect sine wave, because the wave has been altered, or *modulated* with the information it is intended to carry.
Think of it as your voice. You can produce a constant tone with your vocal chords, but you aren’t actually telling anybody anything until you alter that tone with your mouth, pitch, tone, etc. You’ve *modulated* your voice in a fashion that is recognizable and understood (language) by your intended audience.
A sine wave is simply the way in which sound an other waveforms manifest, because the way in which they’re created involves some form of oscillation. And that’s represented in the smooth wave pattern of a Sine. Other types of waveforms are simply just zoom d out versions of a sine wave, and it makes more sense to visualize it when thinking about what sound each creates.
A Saw wave makes a sort of buzzing sound, and the shape shows why; it’s essentially a chord that decreases in intensity. Zooming in on the shape shows multiple sine waves that are offset and at different heights.
A Square wave makes a flat sound, and again, the shape of the wave shows why; it’s a sine wave with no attack or decay.
A triangle wave is just an offset saw wave, so it adds a bit of attack.
What I think you mean by other radio waves, is Noise, which is just a wave form that keeps changing between both, it’s frequency and height, as well as the waveform type. It’s still just a sine wave, but it’s not uniform anymore. Because I’m order to create recognizable sound, look a song or voice, the wave needs to change.
There is also white noise, but that’s just noise that doesn’t resolve to anything and so sounds like static. As that is, exactly what it is: noise without information.
A sinusoid is a perfect wave-shape, regular, smooth, continuous, no spikes, gaps or jerks, and with a regular repeating pattern.
The mathematical function called sine generates just one type of sinusoidal wave, but by adjusting the parameters you can generate all sorts of things [1].
Radio waves are also just waves. They happen to follow, like many things in natural from tides and individual ocean waves (gosh, I wonder why these shapes are called waves?) to day/night patterns etc., the same kind of shape as a sinusoid.
A wave isn’t something special, there aren’t sine waves and radio waves. Radio happens to oscillate in a nice frequency if you make it do that, and audio oscillates in different frequencies but if you look at individual “perfect” notes then it’s often a sinusoidal wave that’s being made by the speaker / eardrum.
A sine wave isn’t a “thing”. It’s just a term for that kind of regular, smooth, continuous, perfect oscillation.
[1] Interestingly, by combining many sine waves of different amplitudes, frequencies and phases, you can generate just about anything. With a thing called a Fourier transform, you can literally transform any data into a set of sinusoidal curves that when added together replicate the original data. If you do it in one dimension: That’s how MP3 works. In two dimensions, that’s how JPEG works. In three dimensions, that’s how MPEG works.
That’s how your ears and sounds and even light works too. The light at Frequency X oscillates in a wave of that frequency. The light at Frequency Y oscillates in a wave of another frequency. Add them all together and you have different colours of light mixing and do it with sound and you have different frequencies combining to make a range of sounds.
https://www.jezzamon.com/fourier/
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