For transmission of the voice and music signals commercial FM radio must broadcast using frequency band range of:

Explanation:

Commercial FM Radio Frequency Band:

Definition: Frequency Modulation (FM) radio broadcasting is a widely used method for transmitting high-fidelity sound, including voice and music, over radio waves. Commercial FM radio stations operate within a specific frequency band, ensuring interference-free communication and uniformity worldwide. The correct frequency band for commercial FM radio broadcasting is 88 MHz to 108 MHz, as specified by international regulatory bodies like the International Telecommunication Union (ITU).

Working Principle of FM Broadcasting: FM broadcasting involves varying the frequency of the carrier wave in accordance with the audio signal being transmitted. Unlike Amplitude Modulation (AM), where the amplitude of the carrier wave is varied, FM provides better sound quality and resistance to noise and interference. The carrier wave frequency remains within the defined FM band (88 MHz to 108 MHz), ensuring compatibility with FM receivers.

Advantages of FM Broadcasting:

• High Sound Quality: FM provides superior audio fidelity compared to AM due to its resistance to amplitude noise and interference.
• Noise Immunity: FM signals are less affected by electrical noise and environmental disturbances, making them ideal for music and voice transmission.
• Bandwidth Efficiency: The allocated bandwidth (200 kHz per station) ensures clear separation between channels, preventing overlap and interference.

Disadvantages of FM Broadcasting:

• Limited Coverage Area: FM signals have a relatively short range compared to AM signals due to their line-of-sight propagation characteristics.
• Higher Infrastructure Costs: FM broadcasting requires more complex and expensive equipment than AM broadcasting.

Applications of FM Broadcasting: FM broadcasting is widely used for:

• Commercial radio stations for music, news, and entertainment.
• Public service announcements and emergency broadcasts.
• Two-way communication systems, such as police radios and aviation communication.

Correct Option Analysis:

The correct option is:

Option 2: 88 - 108 MHz

This frequency range is the internationally designated band for FM radio broadcasting. It ensures standardized communication for commercial FM radio worldwide. Each FM station is allocated a specific frequency within this range, typically separated by a bandwidth of 200 kHz to avoid interference.

Important Information

To further understand the analysis, let’s evaluate the other options:

Option 1: 200 kHz to 10.7 MHz

This option is incorrect because the range does not align with the standard FM broadcasting band. While 200 kHz represents the typical bandwidth allocated for individual FM stations, the lower limit (200 kHz) and upper limit (10.7 MHz) do not correspond to the FM frequency band. Additionally, 10.7 MHz is often associated with the intermediate frequency (IF) used in FM receivers for signal processing, not the actual broadcast frequency range.

Option 3: 110 MHz to 150 MHz

This range is incorrect for commercial FM broadcasting. Frequencies above 108 MHz are typically reserved for other purposes, such as air navigation aids (e.g., VHF omnidirectional range or VOR) and other communication systems. FM broadcasting operates strictly within the 88 MHz to 108 MHz range.

Option 4: 22 - 66 MHz

This frequency range is incorrect for FM broadcasting. Frequencies in this range are often used for other communication purposes, such as television broadcasting (VHF channels) or amateur radio, but they do not fall within the FM radio band.

Conclusion:

The FM broadcasting band of 88 MHz to 108 MHz is standardized worldwide for transmitting high-quality voice and music signals. Understanding the correct frequency range is essential for designing and operating FM radio systems. While the other options reference valid frequency ranges for specific applications, they do not pertain to commercial FM radio broadcasting. FM's superior sound quality, noise immunity, and efficient bandwidth usage make it the preferred choice for commercial audio broadcasting.