Zusammenfassung der Ressource
DATA AND SIGNALS
- analog signals
- periodic
- continous repetitive pattern whitin time frame
- non- periodic
- composite perioddic analog signal is
composed of multiple sine waves
- sine wave
- amplitude
- period
- frequency
- phase
- composite signals
- a single frequency sine wave is not useful in data
communication, we need to send a composite signal
- digital signals
- described by bit interval(instead of period) and bit
rate (instead of frequency)
- Nyquist bit rate
- BitRate = 2 x bandwidth x log2 L
(L=the number of signal level used)
- shannon capacity
- Capacity = B x log2 (1 + SNR)
SNR=the signal-to-noise ratio
- transmission impairment
- noise
- thermal noise
- induced noise
- crosstalk
- impulse noise or spike
- distortion
- attenuation
- performance of network
- troughput
- propagation and transmission time
- queuing time
- bandwith
- latency
- digital to digital convertion
- line coding
- block coding
- scrambling