Question

Which of the following statements is/are correct?

1. Any device that converts one form of energy into another can be termed a Transducer.

2. Information converted in electrical form and suitable for transmission is called a signal.

3. Unwanted signals that tend to disturb the transmission and processing of message signals in a communication system is termed as Noise.

1. 1 and 2 only
2. 3 only
3. 1 and 3 only
4. 1, 2 and 3

Answer 1

Correct Answer - Option 4 : 1, 2 and 3

The correct answer is 1, 2, and 3.

Transducer:

• Any device that converts one form of energy into another can be termed as a transducer. Hence, Statement 1 is correct.
• In electronic communication systems, we usually come across devices that have either their inputs or outputs in the electrical form.
• An electrical transducer may be defined as a device that converts some physical variable (pressure, displacement, force, temperature, etc) into corresponding variations in the electrical signal at its output.

Signal:

• Information converted in electrical form and suitable for transmission is called a signal. Hence, Statement 2 is correct.
• Signals can be either analog or digital. Analog signals are continuous variations of voltage or current.
• They are essentially single-valued functions of time. The sine wave is a fundamental analog signal.
• All other analog signals can be fully understood in terms of their sine wave components.
• Sound and picture signals in TV are analog in nature.
• Digital signals are those which can take only discrete stepwise values.
• A binary system that is extensively used in digital electronics employs just two levels of a signal.
• ‘0’ corresponds to a low level and ‘1’ corresponds to a high level of voltage/ current.
• There are several coding schemes useful for digital communication.
• They employ suitable combinations of number systems such as the binary coded decimal (BCD).
• American Standard Code for Information Interchange (ASCII) is a universally popular digital code to represent numbers, letters, and certain characters. 

Noise:

• Noise refers to the unwanted signals that tend to disturb the transmission and processing of message signals in a communication system. Hence, Statement 3 is correct.
• The source generating the noise may be located inside or outside the system.