Here is a more detailed description of what I was talking about:
It is possible to convert information from analog into digital form and back again without losing details. Although the electronic circuits to do this can be quite complex, the basic idea is fairly simple. To see how it works we can consider turning the analog waveform into a string of binary numbers.
The waveform shown below represents the kind of analog pattern generated by telephones. These waves are converted into digital patterns for transmission by taking a series of samples. Each sample represents the wave's voltage level at a specific moment. Let's focus here on just one sample, the one represented by the orange blob.
I can't figure out to paste image here
The first step in sampling the waveform is to choose a signal range - a range of voltage levels large enough to cover all the variations, up and down, that the signal makes.
The next step is to divide the range into two equal halves. (In the diagram this 'cut' is shown by the red line.) We then ask "Is the point we're sampling above this line?" If it is above the line we note down a '1', is below we note down a '0'.
We now divide the 'half-range' which the sample occupies into two equal halves. (Since in this case it is the top half, this division is at the yellow line.) Once again we ask "Is the sample above the line?" If above we tack '1' on to our previous answer, if below we tack on a '0'.
In this case the sample we are looking at (the orange blob) is above the first (red) line and below the second (yellow) line, so we collect he result '10' from our first two uses of this 'divide and question' method.
We can repeat this process as many times as we like, each time gaining another bit of information about the point whose level we are trying to determine. In the example we have done this a third time (the blue line). As a result we can say that the level is in the band of voltages we can represent by the number '101'. The more times we divide the range and answer the question about which side of the line the sample lies on and , the more bits of information we get. As the number of bits increases so we know the precise level more accurately. In practice we can stop asking after a while because we will reach the level when random noise blurs the signal, making any further bits meaningless.
By taking a series of samples - each time using this 'yes/no' process - we can convert all the details of the analog waveform into a stream of binary numbers. For example, the above wave can be represented by the series: '110 110 111 111 101 100 011 etc. ..." by taking three bits per sample for the sampled points indicated by the circles. In fact, we can see that we should have taken more bits per sample and used more samples to convert all the details of this particular wave. This would increase the number of bits we would get (i.e. more information since information is measured in bits), but the argument is just the same as above.
The above may give you some idea of how important sampling rates are in regard to a finer resolution of the analog signal. It's not real easy to explain but this comes close.
