Questions and Answers
Which component of a communication system is responsible for converting an electrical signal into a suitable form for transmission?
What is the primary function of a demodulator within a receiver?
What does the signal-to-noise ratio (SNR) signify in electronic communications?
What does attenuation in a communication system refer to?
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Which type of communication allows for two-way interaction but not simultaneously?
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How do digital signals differ from analog signals?
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Which of the following does NOT represent a communication channel?
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Which type of device can function both as a transmitter and a receiver?
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What is the primary purpose of modulation in electronic communication?
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What does baseband transmission involve?
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Study Notes
Communication Systems
- A communication system consists of components such as transmitters, receivers, communication channels, and sometimes transceivers.
- Transmitter: Converts electrical signals for transmission. Includes oscillators, amplifiers, and modulators.
- Communication Channel: Medium for signal transmission, including wire conductors, fiber optics, and free space.
- Receiver: Converts transmitted messages back into an understandable form, contains filters, demodulators, and amplifiers.
- Transceivers: Integrated devices that function as both transmitters and receivers, sharing circuits and power supply.
- Attenuation: Signal loss proportional to the square of the distance between transmitter and receiver.
- Noise: Undesired signals that affect communication quality, measured by the Signal-to-Noise Ratio (SNR) in decibels (dB).
Types of Electronic Communications
- Simplex: One-way communication.
- Duplex: Two-way communication, but not simultaneously.
- Full-Duplex: Two-way communication occurring simultaneously.
Signal Types
- Analog Signal: Continuously varying voltage or current resembling the information, such as voice and video.
- Digital Signal: Discrete, step-like changes, commonly utilizing binary codes.
Modulation and Multiplexing
- Modulation: Process of varying a higher frequency carrier signal to make it compatible for transmission.
- Multiplexing: Allows multiple signals to share the same communication medium, maximizing efficiency.
- Baseband Transmission: Direct transmission of original signals without modulation.
- Broadband Transmission: Uses a carrier signal modified by the baseband signal for transmission.
Common Modulation Techniques
- Amplitude Modulation (AM): Varies the amplitude of the carrier signal based on the modulating signal.
- Frequency Modulation (FM): Varies the frequency of the carrier signal in accordance with the modulating signal.
- Phase Modulation (PM): Varies the phase angle of the carrier signal and mimics FM characteristics.
- Frequency Shift Keying (FSK): Converts data into varying tones based on frequency.
- Phase Shift Keying (PSK): Introduces phase shifts in the signal for data transmission.
Multiplexing Types
- Frequency Division Multiplexing (FDM): Different subcarriers operate on separate frequencies for each signal.
- Time Division Multiplexing (TDM): Multiple signals are sampled sequentially, allowing shared use of the carrier.
- Code Division Multiplexing (CDM): Signals are uniquely coded and transmitted faster in binary form.
The Electromagnetic Spectrum
- Electromagnetic waves oscillate with electric and magnetic field intensities varying sinusoidally over time.
- The spectrum encompasses all frequencies of electromagnetic signals but does not include signals carried by cables.
- Commonly used frequencies for communication include those for two-way communication, TV, and wireless technologies.
- Frequency: Determines the number of cycles per second a phenomenon occurs, linked to heat generation and signal detection.
Optical Spectrum
- Visible Spectrum: Light wavelengths range from 400 to 800 nm; modulated light can be transmitted through glass fiber.
- Ultraviolet Spectrum: Ranges from about 4 to 400 nm; primarily used in medical applications rather than communication.
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Description
This quiz covers the fundamentals of communication systems including types of electronic communication, modulation, multiplexing, and noise analysis. Test your understanding of how transmitters and the electromagnetic spectrum function within these systems.
