Transmission Basics In data networking, transmit means to issue signals to the network medium Transmission refers to either the process of transmitting or the progress of signals after they have been transmitted | Chapter 3 Transmission Basics and Networking Media Transmission Basics In data networking, transmit means to issue signals to the network medium Transmission refers to either the process of transmitting or the progress of signals after they have been transmitted Analog and Digital Signals Information transmitted via analog or digital signals Signal strength proportional to voltage In analog signals, voltage varies continuously and appears as a wavy line when graphed over time Wave’s amplitude is a measure of its strength Frequency: number of times wave’s amplitude cycles from starting point, through highest amplitude and lowest amplitude, back to starting point over a fixed period of time Measured in Hz Analog and Digital Signals (continued) Wavelength: distance between corresponding points on a wave’s cycle Phase: progress of a wave over time in relationship to a fixed point Analog transmission susceptible to transmission flaws such as noise Digital signals . | Chapter 3 Transmission Basics and Networking Media Transmission Basics In data networking, transmit means to issue signals to the network medium Transmission refers to either the process of transmitting or the progress of signals after they have been transmitted Analog and Digital Signals Information transmitted via analog or digital signals Signal strength proportional to voltage In analog signals, voltage varies continuously and appears as a wavy line when graphed over time Wave’s amplitude is a measure of its strength Frequency: number of times wave’s amplitude cycles from starting point, through highest amplitude and lowest amplitude, back to starting point over a fixed period of time Measured in Hz Analog and Digital Signals (continued) Wavelength: distance between corresponding points on a wave’s cycle Phase: progress of a wave over time in relationship to a fixed point Analog transmission susceptible to transmission flaws such as noise Digital signals composed of pulses of precise, positive voltages and zero voltages Positive voltage represents 1 Zero voltage represents 0 Analog and Digital Signals (continued) Binary system: uses 1s and 0s to represent information Easy to convert between binary and decimal Bit: a single binary signal Byte: 8 bits Typically represents one piece of information Overhead: describes non-data information that must accompany data for a signal to be properly routed and interpreted Data Modulation Figure 3-5: A carrier wave modified through frequency modulation Transmission Direction: Simplex, Half-Duplex, and Duplex Simplex transmission: signals may travel in only one direction Half-duplex transmission: signals may travel in both directions over a medium Only one direction at a time Full-duplex or duplex: signals free to travel in both directions over a medium simultaneously Used on data networks Channel: distinct communication path between nodes May be separated logically or .
