Digital sampling

When we sample an analogue signal, we take measurements of the analogue signal at regular intervals.
That means that we measure the amplitude of the analogue signal every, say, 1/44,100th of a second. We then convert those measurements each into a digital signal, which gives us a digital ‘equivalent’ of the analogue signal.

It’s not exactly the same as the original analogue signal, but it’s a close approximation.

Improving quality

• If we take more samples (measure the analogue signal more frequently), we get a better approximation of the original analogue signal, but it takes up more storage space.
• If we store each analogue signal measurement using more bits, we can represent more values, which gives us a better approximation of the original analogue signal, but again, takes up more storage space.
• Sometimes, we can use a better algorithm to convert the analogue signal into a more accurate digital signal. They can take more processing power, in cases, though.

Sample rate

The sample rate is just the number of samples we take per second.

FOr example, CD quality audio has a sample rate of 44,100 samples per second. That means that every second, we’ve taken 44,100 measurements of the analogue signal, and converted those into a digital signal.

The higher the sample rate, the better the quality of the digital signal, but it also takes up more storage.

Bit depth

The bit depth is the number of bits we use to store each sample.

For example, CD quality audio has a bit depth of 16 bits. That means that each sample is stored using 16 bits, which allows us to represent 2^16 = 65,536 different values for each sample.