In practice, Frequency Modulation (FM) is a type of analog modulation, where carrier wave frequency is varied by the information or message signal that carries the baseband information. The most common FM signals are the transmitted audio signals via FM radio communications. On the other hand, Radio Broadcast Data Systems (RBDSs), which are digital data with low bandwidth digital information, can be also transmitted by the FM radio. The operation range of FM signals’ frequency is 88-108 MHz, where this makes these signals less vulnerable to both the orientation and presence of humans and objects with small sizes. In addition, FM signals are mainly stronger than Wi-Fi signals due to their ability to simply cover large areas with offering efficient indoors penetration. Thus, the use of these signals eliminates the need to using custom infrastructures. In addition, the majority of mobile devices composed of FM radio receivers, which are cheaper and consume less power than those of Wi-Fi signals. Particularly, the simplest way to generate FM signals is the application of the message signal to the control voltage of the Voltage-Controlled Oscillator (VCO) directly. It then offers a carrier sinusoidal wave that has constant amplitude and a control voltage based frequency. Thus, the carrier wave is a function of the message signal; it is the same as its center frequency when there is no message signal, while the output signal instantaneous frequency varies below and above this frequency when there is a message signal. 2 Based on the FM output signal, two observations can be defined. The FM signal amplitude is constant despite of the message signal, where this results in constant envelope property. In addition, the frequency-modulated output is nonlinearly based on the message signal. Thus, the FM signal properties cannot be easily analyzed. On the other hand, the FM signal bandwidth can be estimated using a tone message signal based on signifying the number of its efficient sidebands. A message signal can be retrieved from the FM signal based on performing a frequency demodulation. It includes a frequency discriminator, where it is a differentiator with a specific envelope detector.