Understanding hertz (Hz) in digital signal processing

Frequency, measured in Hertz (Hz), quantifies the rate of a cyclical phenomenon. In the context of digital signal processing, Hz is employed to characterize the properties of sound waves. For instance, a sound wave with a frequency of 1000 Hz undergoes 1000 cycles every second.

Sampling rate​

The sampling rate, measured in Hz, is how frequently an analog signal is sampled and converted into digital data points. A higher sampling rate means that more samples are taken per second, resulting in a more accurate representation of the original analog signal, especially for capturing high-frequency elements.

For example, think of an audio signal with various frequencies. If the sampling rate is too low, high-frequency audio elements, such as sharp sounds or nuances in the music, may not be accurately captured. This can lead to aliasing or distortion in the digital representation of the signal.

In contrast, a higher sampling rate allows for more frequent analog signal sampling, capturing a wider range of frequencies and preserving the fidelity of the original sound. This is particularly important in audio recording and reproduction to ensure that subtle details and nuances are faithfully reproduced in the digital format.

How to convert hertz to milliseconds​

First, remember that Hz tells you how many cycles something makes in a second. Milliseconds, on the other hand, measure time in thousandths of a second. So, Hz is how often something happens, while ms is how long it takes.

Now, to convert Hz to ms, you have to invert the fraction. That is, take one and divide it by the number of Hz you have. But that's not enough! Since milliseconds are a lot smaller than seconds, you've got to take the answer up a notch by multiplying it by 1000. That way, you're accounting for the difference in scale between the two units.

For example, if you have a signal at 100 Hz, then dividing one by 100 gives you 0.01. But that's in seconds, so you have to multiply by 1000 to get 10 milliseconds, which is the actual time for one cycle of that signal.
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Mpumelelo von Mumhanzi
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