What is the frequency deviation formula?

The frequency deviation formula is used in the context of frequency modulation (FM) in telecommunications and signal processing. FM is a modulation technique where the frequency of a carrier signal varies in accordance with the amplitude of a modulating signal. The formula for frequency deviation (Δf) in FM is as follows:

Δf = kf * Amplitude of the Modulating Signal

Where:

Δf is the frequency deviation, which represents how much the carrier frequency deviates from its center frequency due to modulation.
kf is the modulation sensitivity or modulation index. It is a constant that depends on the specific modulation scheme and the characteristics of the modulating signal. In some cases, it's also denoted as Δf/Amplitude of the Modulating Signal.
Amplitude of the Modulating Signal is the peak amplitude of the signal that is modulating the carrier.
In practical FM systems, the modulation index (kf) is an important parameter that determines the extent to which the frequency of the carrier wave is modulated by the information signal. When the modulation index is small, the frequency deviation is also small, resulting in narrowband FM. Conversely, when the modulation index is large, the frequency deviation is large, leading to wideband FM.

It's important to note that the exact formula for frequency deviation and the value of kf may vary depending on the specific FM modulation scheme being used, such as narrowband FM, wideband FM, or other variations of frequency modulation. The formula provided above is a general representation.