Digital Modulation Techniques Quiz

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Questions and Answers

What is an advantage of amplitude shift keying (ASK)?

It provides a high signal to noise ratio.

It is less sensitive to noise interference.

It can transmit digital data over optical fiber. (correct)

It has higher power efficiency than FSK.

What characteristic of frequency shift keying (FSK) remains constant during modulation?

Amplitude of the carrier signal (correct)

Power consumption

Frequency of the carrier signal

Data transmission rate

Which of the following is a disadvantage of frequency shift keying?

It uses larger bandwidth compared to ASK. (correct)

It has a higher signal to noise ratio.

It has simple transmitter and receiver implementations.

It provides high data rate transmission.

How is the frequency measured?

In hertz (Hz), representing cycles per second Signup and view all the answers

What is a common advantage of phase shift keying (PSK)?

It modifies the phase of the carrier while maintaining amplitude and frequency. Signup and view all the answers

In which scenario would frequency shift keying (FSK) be preferable over amplitude shift keying (ASK)?

When a high signal to noise ratio is needed. Signup and view all the answers

What is defined as one complete wave of alternating current?

Cycle Signup and view all the answers

What is the primary focus of network resource management?

Controlling data transmissions effectively Signup and view all the answers

What is the primary characteristic of Binary Phase Shift Keying (BPSK)?

It involves a phase shift of 180 degrees between binary values. Signup and view all the answers

Which advantages does Phase Shift Keying (PSK) have over Amplitude Shift Keying (ASK)?

Greater power efficiency. Signup and view all the answers

Which statement best describes Quadrature Phase Shift Keying (QPSK)?

It can encode two bits onto one symbol using four phase shifts. Signup and view all the answers

What is a significant disadvantage of Phase Shift Keying (PSK)?

It has a low bandwidth efficiency. Signup and view all the answers

Which option accurately describes the Client-Server Network model?

It centralizes resource sharing by having dedicated servers. Signup and view all the answers

In which scenario is a Peer-to-Peer Network more advantageous than a Client-Server Network?

For straightforward and decentralized resource sharing. Signup and view all the answers

What would be a typical application where BPSK is preferred?

Long distance wireless communication. Signup and view all the answers

Which is a disadvantage commonly associated with the Client-Server Model?

Higher vulnerability to network failures. Signup and view all the answers

What is the purpose of dividing the amplitude range into L zones during quantization?

To enable the selection of quantized values Signup and view all the answers

How is the normalized pulse amplitude modulation (PAM) value calculated?

By dividing amplitude by the zone height d Signup and view all the answers

What is the relationship between quantization levels (L) and the number of bits per sample (n)?

n bit = log 2 L Signup and view all the answers

In delta modulation, what does a recorded bit of 1 indicate?

The input signal is higher than the last staircase value Signup and view all the answers

What is the main advantage of using adaptive delta modulation over standard delta modulation?

It adjusts the modulator's step size based on signal changes Signup and view all the answers

What is the primary function of the demodulator in delta modulation?

To create the analog signal from digital data Signup and view all the answers

What does quantization error represent?

The difference between the actual amplitude and quantized value Signup and view all the answers

What essential characteristic distinguishes delta modulation from pulse code modulation (PCM)?

Delta modulation records changes from the previous value rather than absolute values Signup and view all the answers

Study Notes

Amplitude Shift Keying (ASK)

ASK transmits digital data over optical fiber.
Receivers and transmitters are simple and inexpensive.
ASK uses less bandwidth than Frequency Shift Keying (FSK), making it more bandwidth efficient.
ASK is susceptible to noise interference, which can lead to data loss.

Frequency Shift Keying (FSK)

FSK modifies the frequency of an analog carrier signal to reflect binary data.
A higher frequency represents a binary high input, while a lower frequency represents a binary low input.
Amplitude and phase of the carrier signal remain constant.
FSK is less prone to noise issues than ASK.
FSK offers a higher signal-to-noise ratio.
Transmitters and receivers are simple for low data rate applications.
FSK uses more bandwidth than ASK, making it less bandwidth efficient.
FSK has lower power efficiency.

Phase Shift Keying (PSK)

PSK modifies the phase of an analog carrier signal to reflect binary data.
Amplitude and frequency of the carrier signal remain constant.

Binary Phase Shift Keying (BPSK)

Also known as 2-phase PSK or Phase Reversal Keying.
The carrier sine wave undergoes two phase reversals (0° and 180°).
BPSK is a Double Side Band Suppressed Carrier (DSBSC) modulation scheme.
Uses a 180° phase shift difference between binary 1 and binary 0.
Considered the most robust digital modulation technique for long-distance wireless communication.

Quadrature Phase Shift Keying (QPSK)

The carrier sine wave undergoes four phase reversals (0°, 90°, 180°, and 270°).
Can be further extended to use eight or sixteen phase values.
Encodes two bits per symbol.
Uses phase shifts of multiples of 90 degrees.
Has double the data rate carrying capacity compared to BPSK.

Advantages of PSK

More power efficient than ASK and FSK.
Less prone to errors.
Carries data more efficiently than FSK.

Disadvantages of PSK

Lower bandwidth efficiency.
Complex detection and recovery algorithms for binary data.
Requires a non-coherent reference signal.

Client-Server Network

A network architecture where a central server manages resources and services for connected clients.
Clients request services and data from the server.
The server provides resources and services to clients.
Examples: Web browsing, email, file sharing.

Peer-to-Peer Network

Each connected node (peer) acts as both a client and a server.
Peers can directly share resources and communicate with each other.
No central authority or server.
Examples: BitTorrent, file sharing applications.

Quantization

The process of converting a continuous analog signal into a discrete digital signal.
The process involves dividing the signal range into a finite number of levels.
Each level is assigned a specific digital value.

Delta Modulation

A simplified digitalization technique compared to Pulse Code Modulation (PCM).
Delta Modulation focuses on changes from the previous sample.
Modulator: Creates a stream of bits representing small changes in the analog signal.
Demodulator: Uses a staircase-like signal and delays to reconstruct the analog signal from the digital data.

Adaptive Delta Modulation

Improves Delta Modulation by adapting the step size based on signal changes.
Allows for more accurate representation of the original signal.
Enhances the performance of Delta Modulation.

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Description

Test your knowledge on different digital modulation techniques such as Amplitude Shift Keying (ASK), Frequency Shift Keying (FSK), and Phase Shift Keying (PSK). This quiz covers their definitions, advantages, disadvantages, and applications. Get ready to dive into the world of signal processing!