>>7908254Let's take an example, storing music.
In the analog world, you just set up something that can store an image of you sound and can fill up with time.
The most spread technique was using a microphone to capture sound (air pressure) as an electricity level (voltage), and then polarize a magnetic band (tesla) according to to the voltage.
Moving the band while doing so allowed to record an image of the sound to the band.
You must pay attention to two dimensions : Time and Magnetization.
The slower you go, the more you write the actual data into the previous one, and the less quality you have (the digital world equivalent is sampling rate).
The more you can magnetize the band, the closer the stored data is compared to the original data (the digital world equivalent is quantization depth).
You could think that an analog tape is better, no matter the depth and the sample rate you use to store the samples.
But...
As said earlier, the band have a speed, and thus limit the sampling rate, and the band is a physical medium with impurities and imperfect magnetic material, giving it a noise.
And...
Digital world is absolute. It has it's pro and cons, but basically, a 1 is always a 1 and a 0 is always a 0.
So you will make an error when quantizing the samples, because you will store a finite value.
And you will lose data between the samples, because the sample rate is fixed.
But 1) the error will be known BEFORE recording 2) the error will ALWAYS stay the same.
And that's better because you can use mathematics to recover data, or to correct some errors. Or you can decide to use more memory to store better quality samples.
So,
A CD stores 16 bit samples at 44.1KHz.
A cassette roughly store the equivalent of ~6bit samples at ~35KHz.
You would have a better sound quality by storing a compressed digital version of the sound onto a cassette than directly in analog form.
That's a quick and funny example, but it's even more relevant when you try do do computations.
Concl.
