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)