Question

1-what are advantages for digital communication?

2-What is the different between Modulation and demodulation?

3-What are the disadvantages of PPM?

4-Where can you use (PWM)?

5-What are the advantages of (PWM)?

Answer 1

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1. Advantages of Digital Communication

• The effect of distortion, noise, and interference is much less in digital signals as they are less affected.
• Digital circuits are more reliable.
• Digital circuits are easy to design and cheaper than analog circuits.

2. Modulation is the process of influencing data information on the carrier, while demodulation is the recovery of original information at the distant end from the carrier. A modem is an equipment that performs both modulation and demodulation.

3. As the position of the PPM pulses is varied with respect to a reference pulse, a transmitter has to send synchronizing pulses to operate the timing circuits in the receiver. Without them, the demodulation would not be possible to achieve.

4. Applications of Pulse Width Modulation (PWM)

• PWM Techniques are used in Telecommunications for encoding purposes.
• Pulse Width Modulation helps in voltage regulation and thus finds its use in controlling Brightness in Smart Lighting Systems and also controls the speed of motors.

5. The main advantage of PWM is that power loss in the switching devices is very low. When a switch is off there is practically no current, and when it is on and power is being transferred to the load, there is almost no voltage drop across the switch.

Answer 2

Answer:

Explanation:

1. What are advantages of digital communication?

Advantages of digital communication

The effect of distortion, noise, and interference is much less in digital signals as they are less affected.

Digital circuits are more reliable.

Digital circuits are easy to design and cheaper than analog circuits.

The hardware implementation in digital circuits, is more flexible than analog.

The occurrence of cross-talk is very rare in digital communication.

The signal is un-altered as the pulse needs a high disturbance to alter its properties, which is very difficult.

Signal processing functions such as encryption and compression are employed in digital circuits to maintain the secrecy of the information.

2. What is the difference between modulation and demodulation?

PARAMETER MODULATION DEMODULATION

Definition Modulation is the process of varying the parameter of the carrier signal according to message bearing signal. Demodulation is the process by which message signal is extracted from the modulated wave.

Operating end Transmitting end Receiving end

Operation Simple Complex

Frequency transformation Low to high High to low

Circuit needed Modulator Demodulator/Detector

3. Disadvantages of PPM

Large bandwidth is required to ensure transmission of undistorted pulses.

4. PWM

Used for motor control

5. Advantages of PWM

Cheap to make

Low power consumption

Efficiency up to 90 %

A signal can be separated very easily at demodulation and noise can be also separated easily  

High power handling capacity

Can utilize very high frequency

Little heat whilst working

Noise interference is less

Very energy efficient when used to convert the voltage or to his light bulb  

A system in moderate inefficiency among all three types

Synchronization between transmitter and receiver is not required unlike pulse position modulation (PPM)

Filter requirement is reduced

Amplitude and frequency can be control independently