Communication Networks (Chapter 3)
Define a wavelength.
The distance traversed of the course of one period.
What is the Nyquist Formula?
C = 2 * B * (log [base 2] M)
What is Shannon Formula?
C = B * (log [base 2] (SNR + 1))
What is Multi-Point?
More than two devices share a transmission medium.
Define what noise is?
Unwanted signals inserted between transmitter and receiver.
What is Attenuation?
When signal strength falls off with distance over any transmission medium. Side Note: Strength can be increased with use of amplifiers or repeaters.
What is the formula created by Shannon for finding the Sound to Noise ratio in decibels?
SNR [dB] = 10 * (log [base 10] (signal power/noise power))
The successful transmission of data depends on two factors which are what?
- Quality of the signal - Characteristics of the transmission medium
What is point-to-point?
A guided transmission medium that provides a direct link between two devices and only those two devices share the medium.
Define a Periodic Signal.
A signal pattern that repeats over time.
Define a Digital Signal.
Signal intensity maintains a constant level and then abruptly changes to another level. - Sequence of voltage pulses.
Define an Analog Signal.
Signal intensity varies smoothly with no breaks. - Represents data with a continuously varying electromagnetic wave.
Define what Simplex means.
Signals transmitted in one direction. Ex.) Television
What are some advantages and disadvantages of Digital Signals?
Advantage: They're cheaper and less susceptible to noise interference. Disadvantage: Suffer more from attenuation
What are the differences between Digital & Analog signals?
Analog signals represent data with a continuously varying electromagnetic wave whereas digital signals represent data with a sequence of voltage pulses.
What is the difference between guided and unguided transmission media?
Guided media uses a physical path whereas unguided uses wireless means to transmit media.
Define a Aperiodic Signal
Pattern is not repeated over time.
What is a direct link?
Th transmission path between two devices with no intermediate devices.
Define a Spectrum.
The range of frequencies contained in a signal.
Define Bandwidth
The width of the Spectrum
Define what Full Duplex means.
When stations transmit simultaneously. Ex.) Telephone
Define what Half Duplex means.
When stations transmit, but only one at a time. Ex.) Walkie-Talkies (Police Radio)