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Questions and Answers
What is the role of the source coder in a transmitter?
What is the role of the source coder in a transmitter?
Which invention was first developed in 1876?
Which invention was first developed in 1876?
What task does the local oscillator (LO) perform in both the transmitter and receiver?
What task does the local oscillator (LO) perform in both the transmitter and receiver?
What significant event occurred in the year 2007?
What significant event occurred in the year 2007?
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Which component in the receiver is responsible for rejecting adjacent channel signals?
Which component in the receiver is responsible for rejecting adjacent channel signals?
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Which frequency range is primarily used for radio and television broadcasting?
Which frequency range is primarily used for radio and television broadcasting?
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What is the main difference between a channel coder and a source coder?
What is the main difference between a channel coder and a source coder?
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Who invented the transistor, and in what year?
Who invented the transistor, and in what year?
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What is the function of the power amplifier (PA) in the transmitter?
What is the function of the power amplifier (PA) in the transmitter?
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Which of the following technologies was introduced in the early 2000s?
Which of the following technologies was introduced in the early 2000s?
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Which of the following best describes the role of the mixer in the receiver?
Which of the following best describes the role of the mixer in the receiver?
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Which significant event is associated with the year 1957?
Which significant event is associated with the year 1957?
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In what way does the IF amplifier (IFA) improve the receiver's performance?
In what way does the IF amplifier (IFA) improve the receiver's performance?
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Which element is primarily responsible for radiating the modulated signal as an electromagnetic wave?
Which element is primarily responsible for radiating the modulated signal as an electromagnetic wave?
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What is the frequency range of the slightly higher VHF that operates television channels 2-4?
What is the frequency range of the slightly higher VHF that operates television channels 2-4?
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Which individual is credited with the invention of radio?
Which individual is credited with the invention of radio?
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Study Notes
Wireless Communication Fundamentals
- Wireless communication systems use a transmitter (Tx) and receiver (Rx) connected by a channel
- Source: origin of information (e.g., voice, data, video)
- Transmitter (Tx):
- Source coder: removes redundant information
- Channel coder: protects against errors introduced by the channel
- Local oscillator (LO): creates a carrier signal
- Modulator: combines the encoded message with the carrier
- Power Amplifier (PA): amplifies the modulated signal
- Antenna (A): transmits the modulated signal as an electromagnetic wave
- Channel: the path (link) between the Tx and Rx (e.g., cable, air/wireless medium)
- Receiver (Rx):
- Antenna (A): receives the incoming electromagnetic wave
- Low-noise amplifier (LNA): amplifies the weak signal
- Mixer: converts the RF signal to IF frequencies
- Intermediate Frequency Amplifier (IFA): amplifies and filters IF signal
- Demodulator: extracts the original message from the modulated signal
- Channel decoder: recovers the original data from the encoded signal
- Source decoder: extracts the original data from the encoded signal to create the original information
- The information flows from the Source to the Transmitter, then through the Channel to the Receiver, and finally to the Destination.
Introduction
- Wireless communication is a broad term encompassing various types like mobile, portable, radio, and personal communications.
- Wireless systems are unique with essential principles like flexible spectrum management and composite wireless infrastructures.
- Key Differences exist with “wired” communications including mobile versus fixed wireless/radio.
- Examples of wireless technology include WiFi, cell phones, remote control, Bluetooth, radio/TV broadcast (including satellite), and navigation (GPS, radar).
Historical Perspective
- 1844: Telegraph invention (Morse)
- 1876: Telephone invention (Bell)
- 1895/96: Radio invention (Popov/Marconi)
- Early 1900s: Initial radio usage and transatlantic transmission
- 1933: FM invention (Armstrong)
- 1936: First TV broadcast (BBC)
- 1947: Transistor invention (Bell Labs)
- 1948: Shannon's information theory discovery
- 1957: Sputnik launch (USSR)
- 1973: First mobile phone call
- 1981: IBM PC launch
- 1990s: Internet launch
- 2000s: WiFi launch
- 2007: iPhone launch
- 2010: iPad launch
- 1998-2008: Rise of social media (Google, YouTube, Facebook, Twitter, etc.)
Wireless Frequency Bands
- Wireless communication uses various frequency bands ranging from very low frequency (VLF) to extremely high frequency (EHF) for diverse applications like communication from a ship's radio to satellite communication.
- Different frequency bands have various uses, including radar, satellite communication, television broadcasting, and radio etc.
- Frequencies range from 100km to 1mm.
- VHF, UHF, and microwave bands are prominently used
Microwave Frequency Bands
- Specific frequency ranges like L-band, S-band, C-band, X-band, Ku-band, K-band, Ka-band are used for different applications
- Uses include weather radar, satellite communication, wireless local area networks (WLAN), terrestrial broadcasting, and microwave ovens.
Frequency Ranges (with examples)
- VLF: Navigation
- LF: Maritime radio navigation
- MF: AM radio
- HF: Shortwave broadcast
- VHF: Television broadcasting
- UHF: Television broadcasting, mobile phones, GPS
- Microwave (SHF): Satellite communication, WLAN, radar
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Description
Explore the essentials of wireless communication systems, including the roles of transmitters and receivers. Understand how signals are processed and transmitted as electromagnetic waves. This quiz covers key concepts such as modulation, amplification, and the communication channel between sender and receiver.
