# Shared Flashcard Set

## Details

Network+2009
Signaling Methods
28
Computer Networking
Professional
03/03/2010

Term
 Analog Signal
Definition
 Carries information in the form of a continuous wave. In networking analog signals are most often generated by electrical current
Term
 Waveform
Definition
 The size, shape and other characteristics that describe the analog signal and information it carries
Term
 Sine Waves
Definition
 A smoothly oscillating curve that is the result of calculating the sine of the angles between zero and 360 degrees and plotting the results
Term
 Amplitude
Definition
 The height(or depth) of the wave from the midpoint between the top and the bottom of the waveform
Term
 Cycle
Definition
 One complete oscillation of an analog signal
Term
 Frequency
Definition
 The number of complete cycles per second in the wave, measured in hertz
Term
 1 Hz is equal to ?
Definition
 One cycle per second
Term
 Phase
Definition
 A description of where a wave's cycle begins in relationship to a fixed point
Term
 Wavelength
Definition
 The distance between to successive peaks in wave form
Term
 Digital Signal
Definition
 Has only two values a binary 1=on and a binary 0=off
Term
 A bit is equal to?
Definition
 a single binary 1 or 0
Term
 A Crumb is equal to ?
Definition
 Two Bits
Term
 A Nibble is equal to ?
Definition
 Four Bits
Term
 A Byte is equal to ?
Definition
 8 Bits
Term
 Modulation
Definition
 A high frequency oscillating signal is used as a base, or carrier, for information. Then a lower frequency data signal is superimposed over the carrier waveform.
Term
 Demodulation
Definition
 When the signal reaches its destination, the receiver decodes the signal, removing the data from the carrier
Term
 Codec
Definition
 Is software or hardware that codes and decodes data to and from analog format.
Term
 What is DAC?
Definition
 Digital to Analog Conversion
Term
Definition
 Analog to Digital Conversion
Term
 Synchronous Communications
Definition
 A byte is sent in a standardized time interval where the receiver assumes that one byte is transmitted every interval.The devices must start and stop their reckoning of these intervals at the same time
Term
 Asynchronous Communications
Definition
 Special start and stop bit patterns are inserted between a byte of data. By watching for these patterns the receiver can distinguish between the bytes of data
Term
 Are Digital Transmissions Modulated?
Definition
 No they are not modulated over a carrier. Data is converted into a digital waveform using "on-off keying," or "Manchester Encoding"
Term
 On-Off Keying
Definition
 Is a digital transmission encoding scheme in which a change in voltage from one state to another within a predetermined interval is symbolized by a 1. No voltage change is symbolized by a 0. The sender must syncronize its clock with the sender by watching for the 1's
Term
 Manchester Encoding
Definition
 Is a way to overcoming the limitations of on-off keying. It represents the transition from positive to ground with a 0 and from negative to positive voltage IN THE MIDDLE OF THE BIT PERIOD it designate a 1
Term
 Serial Data Transmission
Definition
 Bits are transmitted ONE PER CLOCK CYCLE over a single tranmission medium
Term
 Parallel Transmission
Definition
 Multiple bits are transmitted over multiple transmission lines. Multiple bits even multiple bytes are transmitted per clock cycle
Term
 Baseband Transmission
Definition
 DIGITAL SIGNALS are sent via a DC pulse over a single UNMULTIPLEXED signal channel(Uses TDM)
Term