Comms 3 Flashcards
Elements of communicaton
- Sender
- Receiver
- Message
- Medium
- Feedback
- the transmission of signals by modulation of electromagnetic waves with frequencies below those of visible light,
Basic radio communication
- He solidify the observation of Hans Christian Oersted (electric field and magnetic field) and Andre Marie Ampere on the association of electric and magnetic.
James Clerk Maxwell
When did Maxwell demonstrated subtle connection between electric and magnetic field
1864
Maxwell solidify the observation of these two
- Hans Christian Oersted
- Andre Marie Ampere
- He supported Michael Faraday’s “a changing magnetic field produces an electric field”
Maxwell
A changing magnetic field produces
Electric field and vice versa
Maxwell incorporated ___ and ___ electromagnetism
- Light
- Wave
- The forerunner of the various carbon microphones that were used in most telephones produced in the 20th century.
David Edward Hughes
When did David Edward Hughes performed a series of experiments in which his equipment transmitted wireless signals
1879 - 1886
Hughes performed a series of experiments in which his equipment transmitted wireless signals up to
500 yards
he produced electromagnetic waves in the laboratory and their susceptibility to rasured their length and velocity.
Heinrich Rudolf Hertz
When did Heinrich Rudolf Hertz produced electromagnetic waves in the laboratory and their susceptibility to rasured their length and velocity.
1885 - 1889
- He showed that the nature of their vibration and reflection and refraction were the same as those of light and heat waves.
Heinrich Rudolf Hertz
- He experimentally demonstrated the transmission and radiation of radio frequency energy
Nikola Tesla
When did Tesla demonstrated the transmission and radiation of radio frequency energy
1802
He was also credited win being the first person to patent radio technology and when
Nikola Tesla (1943)
He proved the feasibility of radio communication
Guglielmo Marconi
he flashed the first wireless signal across the English Channel
Guglielmo Marconi
When did Guglielmo Marconi flashed the first wireless signal
1899
What letter was flashed by Guglielmo Marconi and where
Letter “S” from England to Newfoundland
- It generates data or message to be transferred.
Source
- Converts non-electrical signal into electrical form.
Input transducer
- used to send out data as radio waves in a specific band of the electromagnetic spectrum
Transmitter
Function of transmitter
- Amplify
- Modulated
- The medium of propagation of the electrical signal data/message signal
Channel
- used to receive data as radio waves in a specific band of the electromagnetic spectrum
Receiver
Function of receiver
- amplify
- demodulate
- Takes electrical signals and converts them into other forms of energy
Output Transducer
- information receiver
Destination
Basic mode of communication
- broadcasting
- p2p communication
- defined as a disturbance which moves through a medium
Waves
- The height of the wave usually measured in metres
Amplitude
Highest part of the wave
Crest
Lowest part of the wave
Trough
- The distance between two consecutive wave crests or between two consecutive wave troughs.
Wavelength
- The number of waves passing a fixed point in a specified period of time.
Frequency
Types of signal
- analog
- digital
This type of signal is continuous variation of current and voltage
Analog
This type of signal is discrete stepwise
Digital
- device that converts one form of energy into another
Transducer
- Loss of quality and strength of the signal while traveling through a medium.
Attenuation
- Increasing the amplitude of a signal using an electrical circuit
Amplification
- Superimposing low-frequency information on a high-frequency carrier wave to overcomes heavy attenuation of low-frequency signals.
Modulation
- Extraction of the original information from the modulated signal at the receiver.
Demodulation
- Frequency range over which the signal is transmitted or equpment operates
Bandwidth
- A device that picks up, amplifies, and re-transmits signals.
Repeater