Telecom formula sheet

Sine wave: y = A sin(2πf t), t = time in seconds, f = frequency in Hertz (cycles/sec), A = amplitude

Square wave: y = sin(2πf t) + 1/3 sin(2π(3f)t) + 1/5 sin(2π(5f)t) + 1/7 sin(2π(7f)t) + ...

Decibels: 10 log₁₀ P_out/P_in

Nyquist: C = 2B log₂ M

Shannon: C = B log₂ (1+SNR)

B = bandwidth, C = max data rate, M = # of signal levels, SNR = signal-to-noise ratio

Thermal noise: N₀ = kT, T in Kelvins, N₀ in Watts/Hz, k = 1.38 x 10^-23 J/K

NRZ: 0=high, 1=low
NRZI: 0 = no transition, 1 = transition
Manchester: NRZI alternating with transitions due to the clock signal
Bipolar-AMI: 0 = no signal, 1 = alternating positive and negative for successive 1-bits
B8ZS: same as bipolar, but 0000 0000 is replaced by 000+−0−+ or 000−+0+−, depending on whether previous 1-bit was + or −.

T-Carrier, other TDM

DS0: 64kbps voice line
DS1: 24 DS0’s plus 1 bit
DS2: 4 DS1’s plus bit-stuffing (pulse-stuffing) room
DS3: 7 DS2’s / 28 DS1’s, plus bit/pulse stuffing room
STS-1: 51.84 Mbps
STS-N: N × STS-1, exactly