CCNA Wireless Chapter 1 Flashcards

8728022852	amplitude	The height from the top peak to the bottom peak of a signal's waveform; also known as the peak-to-peak amplitude.	0
8728022853	band	A contiguous range of frequencies.	1
8728022854	bandwidth	The range of frequencies used by a single channel or a single RF signal.	2
8728025672	Barker code	An 11-bit sequence of encoded bits that represents a single data bit.	3
8728025673	carrier signal	The basic, steady RF signal that is used to carry other useful information	4
8728029489	channel	An arbitrary index that points to a specific frequency within a band.	5
8728029490	chip	A bit produced by a coder	6
8728031773	CCK (stands for)	Complementary Code Keying (acronym)	7
8728031774	dB decibel	A logarithmic function that compares one absolute measurement to another	8
8728035762	dBd	The gain of an antenna, measured in dB, as compared to a simple dipole antenna.	9
8728035763	dBi	The gain of an antenna, measured in dB, as compared to an isotropic reference antenna.	10
8728035764	dBm	The power level of a signal measured in dB, as compared to a reference signal power of 1 milliwatt.	11
8728039817	demodulation	The receiver's process of interpreting changes in the carrier signal to recover the original information being sent.	12
8728039818	DBPSK stands for	differential binary phase shift keying	13
8728044048	DQPSK stands for	differential quadrature phase shift keying	14
8728044049	DSSS stands for	direct sequence spread spectrum	15
8728049169	EIRP stands for	effective isotropic radiated power	16
8728052571	frequency	The number of times a signal makes one complete up and down cycle in 1 second.	17
8728052572	FHSS stands for	frequency hopping spread spectrum	18
8728052573	Hz hertz	A unit of frequency equaling one cycle per second.	19
8728054934	in phase	The condition when the cycles of two identical signals are in sync with each other.	20
8728054935	isotropic antenna	An ideal, theoretical antenna that radiates RF equally in every direction.	21
8728057592	link budget	The cumulative sum of gains and losses measured in dB over the complete RF signal path; a transmitter's power level must overcome the link budget so that the signal can reach a receiver effectively.	22
8728057593	modulation	The transmitter's process of altering the carrier signal according to some other information source.	23
8728060477	narrowband	RF signals that use a very narrow range of frequencies	24
8728060480	noise floor	The average power level of noise measured at a specific frequency.	25
8728062949	OFDM stands for	orthogonal frequency-division multiplexing	26
8728062950	out of phase	The condition when the cycles of one signal are shifted in time in relation to another signal.	27
8728065511	phase	A measure of shift in time relative to the start of a cycle; ranges between 0 and 360 degrees.	28
8728065512	QAM stands for	quadrature amplitude modulation	29
8728065513	RF radio frequency	The portion of the frequency spectrum between 3 kHz and 300 GHz.	30
8728067478	RSSI stands for	received signal strength indicator	31
8728067479	sensitivity level	The RSSI threshold (in dBm) that divides unintelligible RF signals from useful ones	32
8728070146	SNR signal-to-noise ratio	A measure of received signal quality, calculated as the difference between the signal's RSSI and the noise floor. A higher SNR is preferred.	33
8728070147	spread spectrum	RF signals that spread the information being sent over a wide range of frequencies.	34
8728070220	symbol	A complete group of encoded chips that represents a data bit.	35
8728073530	wavelength	The physical distance that a wave travels over one complete cycle.	36
8728112601	coder	A function that converts data bits into multiple encoded bits before transmission, to provide resilience against noise and interference.	37
8728125741	CCK Deffinition	An encoding method that takes either 4 or 8 data bits at a time to create a 6-bit or 8-bit symbol, respectively. The symbols are fed into DQPSK to modulate the carrier signal.	38
8728154827	DBPSK Deffinition	A modulation method that takes 1 bit of encoded data and changes the phase of the carrier signal in one of two ways.	39
8728169651	DQPSK Deffinition	A modulation method that takes 2 bits of encoded data and changes the phase of the carrier signal in one of four ways	40
8728169652	DSSS Deffinition	A wireless LAN method where a transmitter uses a single fixed, wide channel to send data.	41
8728172333	EIRP Deffinition	The resulting signal power level, measured in dBm, of the combination of a transmitter, cable, and an antenna, as measured at the antenna.	42
8728189444	FHSS Deffinition	A wireless LAN method where a transmitter "hops" between frequencies all across a band.	43
8728206218	OFDM deffinition	A data transmission method that sends data bits in parallel over multiple frequencies within a single 20-MHz-wide channel. Each frequency represents a single subcarrier.	44
8728225594	QAM Deffinition	A modulation method that combines QPSK phase shifting with multiple amplitude levels to produce a greater number of unique changes to the carrier signal. The number preceding the QAM name designates how many carrier signal changes are possible.	45
8728234367	RSSI Definition	The measure of signal strength (in dBm) as seen by the receiver. RSSI is normally negative (0 to -100) because the received signal is always a degraded form of the original signal that was sent.	46