The decibel scale is a relative scale. This means it is always comparing two values. In diagnostic ultrasound the decibel scale can be used to express changes in Power, Intensity, Amplitude, and Voltage.
The decibel scale can also be used to express the system's dynamic range, as well as attenuation and gain.
The decibel scale is also a logarithmic scale. In order to understand decibels, you should first have a good understanding of common logarithms. Click this link to access a video I created to help you.
I have also created a video that will help reinforce your understanding of decibels. You can access that video here.
If you would like additional practice with decibels, be sure to access the Decibel Worksheet and Answer Key
If you like, you can download a decibel meter app for your phone: iOS Android