ITM301-ch5 - ITM301 Ch 5[Network Cabling Transmission Basics Analog Signaling such as electromagnetic waves in the air or in copper wire vary infinitely

ITM301-ch5 - ITM301 Ch 5[Network Cabling Transmission...

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ITM301- Ch. 5 [Network Cabling] Transmission Basics Analog Signaling: such as electromagnetic waves in the air or in copper wire, vary infinitely and continuously and appear as a wavy line when graphed over time, characterized by 4 fundamental properties: o Amplitude: a measure of a signal’s strength at any given point in time (on a graph it’s the height of the wave at any point in time) o Frequency: the number of times that a wave’s amplitude cycles from its starting point through its highest amplitude and its lowest amplitude and back to its starting point over a fixed period of time o Wavelength: the distance between corresponding points on a wave’s cycle between one peak and the next, expressed in meters or feet, for electromagnetic waves, a wave’s wavelength is inversely proportional to its frequency (i.e. Higher the frequency, lower the wavelength) o Phase: the progress of a wave over time in a relationship to a fixed point One drawback to analog signaling is that they have infinite variations which are susceptible to transmission flaws like noise or any type of interference that may degrade a signal Digital Signaling: composed of pulses of precise, positive voltages and zero voltages, its either on or off there nothing infinite or continuous Data Modulation Modem: reflects the device’s function as a modulator/demodulator, it modulates digital signals into analog signals at the transmitting end, then demodulates analog signals into digital signals at the receiving end Modulation: a simple wave, called a carrier wave is combined with another analog signal known as the information or data wave to produce a unique signal that gets transmitted from one node to another o The carrier wave is only a messenger FM (frequency Modulation): make a signal conform to a specific pathway (like FM radio) where the data must travel along a particular frequency AM (amplitude modulation): the amplitude of the carrier signal is modified by the application of the data signal. Modulation may also be used to issue multiple signals to the same communications channel and prevent the signals from interfering with one another Baseband: refers to transmissions that are carried on a single channel, with no other transmission sharing the media (Ex. Ethernet) Broadband: refers to technologies in which multiple transmissions share a single media (ex. Cable TV and cable Internet share the same coaxial cable)
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Multiplexing:
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