Question

In modulation process radio signal is called (A) modulating wave (B) Carrier wave (C) modulated wave (D) transmitting wave

Short answer

In the modulation process, a low-frequency message signal (modulating wave) is superimposed on a high-frequency carrier signal (carrier wave). The resulting wave after the modulation process is called modulated wave. Thus, the radio signal in the modulation process is referred to as (B) Carrier wave.

Step-by-step solution

Concept of Modulation

In the modulation process, a low-frequency message signal (also known as the modulating signal) is superimposed on a high-frequency carrier signal. This process alters the characteristics of the carrier wave according to the message signal. The resulting modulated wave is then transmitted over long distances using an antenna.

Understanding the Options

Now, let's analyze the given options and match them with the concepts of modulation: (A) Modulating Wave: This refers to the low-frequency message signal that we want to transmit. (B) Carrier Wave: This is the high-frequency signal that is used to carry the modulating signal. (C) Modulated Wave: This is the final wave that is generated after the modulation process, which contains both the message and carrier signals. (D) Transmitting Wave: This term may refer to a signal that is being transmitted, but it isn't specific to the radio signal in the modulation process.

Identifying the Correct Option

From our discussion of the different terms related to the modulation process, it is clear that the radio signal in the modulation process is actually the high-frequency signal used to carry the message signal. Therefore, the correct answer is: (B) Carrier wave

Key concepts

Carrier Wave

A carrier wave is a high-frequency electromagnetic wave that serves as the foundation for the modulation process.
It is responsible for carrying the modulating signal over various distances. Key characteristics of the carrier wave include:

• Frequency: The carrier wave usually operates at a much higher frequency than the modulating signal. This high frequency is crucial as it allows the transmission of signals over long distances with minimal interference.


• Stability: The carrier wave must be stable to ensure that the modulated wave remains clear and reaches its destination without distortion.


• Amplitude and Phase: Changes in these properties are used during modulation to encode the information from the modulating signal.

To sum up, the role of the carrier wave is integral to the transmission of radio and television signals, and its stability and high frequency form the backbone of effective communication.

Modulating Signal

The modulating signal, also known as the message signal, is the main information holder in the modulation process.
It typically has a lower frequency compared to the carrier wave. Several important aspects include:

• Information Content: This signal contains the content or data intended for transmission, such as audio, video, or data files.


• Low Frequency: Due to its low frequency, it cannot be transmitted over long distances on its own, which is why it relies on the carrier wave.


• Bandwidth: The bandwidth of the modulating signal dictates the range of frequencies it contains; this, in turn, affects the width of the modulated wave.

The interaction of the modulating signal with the carrier wave during the modulation process gives rise to the modulated wave, effectively enabling long-distance communication of the original content.

Modulated Wave

The modulated wave is the resulting signal after combining the carrier wave with the modulating signal.
It integrates characteristics of both these inputs to ensure efficient transfer of information. Key elements include:

• Integration of Signals: The modulated wave incorporates the high-frequency carrier and the low-frequency modulating signal, altering either the amplitude, frequency, or phase of the carrier wave.


• Properties: The modulated wave retains the high frequency of the carrier wave for propagation while also carrying the modulating signal's information content.


• Transmission: This wave is suitable for transmission through various media, allowing the original low-frequency information to be sent over long distances.

Overall, the modulated wave is the key output of the modulation process, crucial for the effective dissemination of information across vast distances and different communication technologies.