Sample Interval

Sample interval is the amount of time between one sample and the next when a sound wave is being digitised. It is a fraction of a second — often a few thousandths or millionths — because a computer takes thousands of measurements every second.

The interval and the sample rate are reciprocals: each one is 1 divided by the other. If a sampler measures the wave every 0.002 seconds, it manages 1 ÷ 0.002 = 500 samples in a second, so the sample rate is 500 hertz.

Shorter interval, more samples

Making the interval shorter means less time passes between measurements, so more samples land on the wave during the same second. That is the same thing as saying the sample rate is higher. The two values always pull in opposite directions: halve the interval and you double the rate.

Turning a rate into an interval

Divide 1 by the sample rate. A rate of 8000 hertz gives an interval of 1 ÷ 8000 = 0.000125 seconds, which is 0.125 milliseconds.