Chapter 2 Data Communications And Computer Networks

Chapter 2 Data Communications And Computer Networks

Data is entities that convey meaning within a computer, while signals are the electric/electromagnetic impulses used to encode/transmit data.
Digital signals can have noise removed from them much easier than analog.
A continuous signal is one that is a continuous waveform, whereas a discrete is one with a choppier waveform.
Amplitude, Frequency, and Phase.
The spectrum of a signal is the range of frequencies that a signal spans from minimum to maximum.
The bandwidth of a signal is the absolute value of the difference between the lowest and highest frequencies of a signal.
It would need to be modulated in order to be transmitted.
With a differential Manchester code every bit has at least one significant change, unlike the NRZ.
It means that it can be decoded without the need for a separate clock signal.
Baud rate is the data transmission rate for modems.
Baud rate signifies symbol rate while bit rate is the number of bits that can be transmitted over a digital network.
Amplitude shift keying, Frequency shift keying, and Phase shift keying.
With post code modulation the analog waveform is sampled at specific intervals, and the snapshots are converted to binary values, whereas with delta modulation an analog waveform is tracked using a binary 1 to represent a rise in voltage, and a 0 to represent a drop in voltage.
It means how many samples that are taken per second.
EBCDIC is an 8 bit code allowing 256 possible combinations of textual symbols, ASCII has various different forms which include a 7 bit version that allows for 128 possible combinations of textual symbols, Unicode is a technique for encoding that provides a unique coding value for each character in every language no matter what the platform is.