Question

In frequency modulation (A) the amplitude of modulated wave varies as frequency of carrier wave. (B) the frequency of modulated wave varies as amplitude of modulating wave. (C) The amplitude of modulated wave varies as amplitude of carrier wave. (D) The frequency of modulated wave varies as frequency of modulating wave.

Short answer

In frequency modulation, the correct statement is that the frequency of the modulated wave varies as the amplitude of the modulating wave (Option B). The amplitude of the modulated wave remains constant, and the carrier frequency changes according to the amplitude of the modulating wave.

Step-by-step solution

Option A: Amplitude of modulated wave varies as frequency of carrier wave

In frequency modulation, the frequency of the carrier wave is altered according to the information signal (modulating wave). However, the amplitude of the modulated wave remains constant. Therefore, this statement is incorrect.

Option B: Frequency of modulated wave varies as amplitude of modulating wave

This statement is correct. In frequency modulation, the frequency of the modulated wave (carrier wave) changes according to the amplitude of the modulating wave. The higher the amplitude of the modulating wave, the greater the change in the carrier frequency.

Option C: Amplitude of modulated wave varies as amplitude of carrier wave

This statement is incorrect. In frequency modulation, the amplitude of the modulated wave remains constant. The frequency of the carrier wave varies as the amplitude of the modulating wave.

Option D: Frequency of modulated wave varies as frequency of modulating wave

This statement is incorrect. In frequency modulation, the frequency of the modulated wave (carrier wave) is altered according to the amplitude of the modulating wave, not the frequency. Based on our analysis, the correct option is: (B) the frequency of modulated wave varies as amplitude of modulating wave.

Key concepts

Amplitude Modulation

In the world of radio communication, amplitude modulation (AM) is a fundamental technique. It involves varying the amplitude, or the strength of the carrier wave, in line with the signal being transmitted (known as the modulating wave).
Imagine you want to send a voice message across a radio frequency. The sound of your voice would be the modulating wave. The carrier wave, like a powerful car, travels longer distances.
By adjusting the "loudness" of your "voice" on this "car," the process helps uncover the information at the receiving end. This ability to change the amplitude creates signals easy for radios to interpret, crucial for traditional AM radio broadcasts.

• The carrier wave frequency remains constant.
• The information (modulating wave) changes the amplitude.
• AM is simple but more prone to interference.

It's important to grasp that in amplitude modulation, the frequency of both the carrier wave and the modulating wave remain unchanged, differing from frequency modulation.

Carrier Wave

A carrier wave is like a blank canvas, used to transmit information over distances. It is a high-frequency electromagnetic wave, providing a stable backbone for transporting a signal. Think of it as a train ready to carry cargo (information). The frequency of this train (carrier wave) is usually kept high enough to travel efficiently over long distances.
This wave itself doesn't contain useful information. However, once we modify certain properties of the carrier wave, like its amplitude or frequency, it can carry the "flavor" of the information embedded upon it, such as music or voice signals.
In both amplitude and frequency modulations, carrier waves play a crucial role, ensuring the effective transmission of signals. Their stable characteristics are what make communication possible over lengthy stretches and through various mediums. Without these carrier waves, transmitting radio stations we enjoy so much wouldn’t reach our homes with such ease.

• High-frequency wave used as a transport."
• Modified to carry signals.
• Works in both amplitude and frequency modulation.

Comprehending this concept is essential for understanding further signal processing methods.

Modulating Wave

The modulating wave is akin to the essence or message you wish to send, like the lyrics to a song or the detailed instructions of a podcast. It is usually low-frequency and contains all the information that needs to be delivered to the listener.
This wave is usually varying in amplitude or frequency over time, carrying all the details in its unique path. In amplitude modulation, it modifies the amplitude of the carrier wave, while in frequency modulation, it adjusts the frequency.
By acting on the carrier wave, the modulating wave exerts changes that embody its information, transforming it into a format ready for transmission. Without it, the carrier wave remains empty, unable to convey meaningful content. These adjustments make it possible for receivers to catch the carried information accurately.

• Usually low-frequency with rich information.
• Alters amplitude or frequency of the carrier wave.
• Transforms information to a transmittable format.

Understanding the modulating wave is key to mastering signal transmission techniques.

Signal Processing

Signal processing involves a series of techniques to manipulate signals to enhance or extract useful information. This vast field scoops around every bit of data, enhancing sound quality, improving transmission, or converting the format from analog to digital, depending on the requirement.
Consider it the chef preparing various ingredients (signals) to perfect the dish. Signal Processing is foundational in creating efficient communication systems, such as mobile networks or streaming services. It ensures data integrity is maintained while improving usability.
With technologies like filtering, modulation, or compression, signal processing achieves its targets. Whether it's clearing noise in a music track or changing the signal into something understandable by electronics, signal processing is crucial.

• Enhances or extracts signal data.
• Improves transmission quality.
• Converts signals between formats.

The essential techniques of signal processing assure that the signals we receive are clear, reliable, and rich in quality.