FM Full Form

What is referred to as Frequency Modulation?

Frequency Modulation, popularly known as FM, is a technique used to encode the data on the alternating digital or analog signal. The method includes varying the carrier wave frequency according to the frequency of modulating signal. A Carrier signal is a signal on which data is imposed, and when it comes to the frequency modulated signal, it is the resulting signal with the variable frequency. 

Working of the Frequency Modulation

The basic principle based on which Frequency Modulation operates is that the amplitude of an analog baseband signal can be represented by a slightly different frequency of a carrier. Similar to the amplitude modulation, the carrier signal in FM is modulated by the input signal. However, the amplitude of the modulated signal remains or is kept constant in the case of Frequency Modulation.

Frequency Modulation operates in a high-frequency range falling between 88 to 108 Megahertz. When it comes to the frequency modulation index, it is often more than 1, and usually, a high bandwidth at the range of 200 kHz is required. The complex circuits with an infinite number of sidebands help receive high-quality signals with high sound quality.

The large value of deviation ( 75 kHz) is often used by the broadcast stations in the VHF portion of the frequency spectrum ranging between 88.5 and 108 MHz. Although these signals support high-quality transmissions, they occupy a large amount of bandwidth. Normally, each wide-band FM transmission can be carried using 200 kHz. Alternatively, the narrowband Frequency Modulation uses deviation figures of approximately 3 kHz. 

FM Modulators

Multiple methods can be used to generate frequency-modulated signals (both direct and indirect), and these are explained as follows:

• Varactor diode oscillator: This method, also known as the voltage-controlled oscillator, is typically used to form Direct FM modulation by directly feeding the message into the input of the oscillator. In this method, a varactor diode placed within the tuned circuit of an oscillator or crystal oscillator circuit is used. When using the crystal oscillators, the signal must be multiplied in the frequency and only narrowband FM can be attained
• Phase-locked loop: The phase-locked loop is an excellent method for generating frequency modulation signals. However, it is important to manage the constraints within the loop with due care. Once everything is done, an excellent solution is offered by this method

Mentioning the advantages of Frequency Modulation

Now that Frequency Modulation offers multiple advantages, it is widely used in the broadcasting and radio communication industry. Following mentioned are some advantages of frequency modulation:

• Resilience to noise: The most important advantage of frequency modulation is its resilience to signal-level variations. The modulation can be carried only as of the variations in frequency which further implies that audio output will not be affected by any signal level variations. This means that the signal can’t fall to the level making it difficult for the receiver to cope. As a result, it can be said that FM is an ideal choice for mobile radio communication applications. Now that FM offers resilience to noise and interference, it can be appropriately used for high-quality broadcast transmissions

• Modulation can be easily applied at the transmitter’s lower power stage: One of the main advantages of frequency Modulation is that it is associated with the transmitters. The application of modulation at the transmitter’s lower power stage is possible. Also, one need not use a linear form of application so that the power level of the signal can be increased to its final value

• Usage of efficient RF amplifiers with frequency-modulated signals: Now that non-linear RF amplifiers can be used to amplify the FM signals in a transmitter, these are more efficient than the linear ones used for the signals with any amplitude variations. This implies that less battery is required for given power output, making Frequency Modulation more viable for portable two-way radio applications

Conclusion

Frequency Modulation is just a technique encoding the data on the alternating digital or analog signal. Due to its widespread commercial use and simplicity, Frequency Modulation is considered the most significant modulation scheme. The broadcasting and radio communication industry, but FM also has many other applications. This guide will walk you through everything one needs to know about Frequency Modulation.