Chapter 1 Formulas and Constants

Question 1

Frequency

Answer 1

f = 1/T

Question 2

Period

Answer 2

Reciprocal of frequency T = 1/f. In seconds

Question 3

Propagation velocity

Answer 3

Vp = Vf * c

Vf = velocity factor unitless
c = speed of Light in vacuum (3 * 10^8)

Question 4

Wavelength

Answer 4

lambda = c/f
lambda = Vp/f

Question 5

Bandwidth, fup, flow, fR, Beff

Answer 5

B = f un - f low
fup = fR + B/2
flow = fR - B/2
fR = (fup - flow)/2
Beff = (pi/2) B

Question 6

Decibel computations:
Power RATIO in dB or GAIN or LOSS
Power RATIO in dB using V
Power RATIO in dB using current A
Power in dB form

Answer 6

PdB = 10 Log(P2/P1)
PdB = 20 Log(V2/V1)
PdB = 20 Log(I2/I1)
PdBW = 10 Log(P/1W)

Question 7

Noise Formulas:
Noise Power
Noise voltage
Noise Current diodes
Total Noise Voltage
Total Noise Current
Total Noise Power

Answer 7

PN = k TB
VN = sqrt ( 4 k TBR)
IN = sqrt( 2B Idc q)
VNT = sqrt ( VN1^2 + VN2^2…)
INT = sqrt ( IN1^2 + IN2^2…)
PNT= PN1 + PN2 +…

T = Absolute temperature in Kelvin
B= bandwidth
k = Boltzmann constant 1.38*10^23 J/K
q= Electron charge 1.602 * 10^-19

Question 8

Harmonic distortion:
●Nth harmonic distortion
●Total harmonic distortion
●Power of signal having distortion

Answer 8

Dn = |An|/|A1|
THD = sqrt( D2^2 +D3^2 … + Dn^2)
P = P0(1+THD^2)

A1 - amplitude of fundamental
An - Amplitude of the nth harmonic
P0 - power without distortion

Question 9

●Signal to noise power ratio
●In dB form
●Noise factor
●noise figure
●Equivalent noise temperature

Answer 9

S/N = Ps/PN
10 log(Ps/PN)
F = SN input / SN output
NF = 10log(F)
Teq = Ta (F-1)

F = noise factor
Ta = standard ambient temp 290 K or 17 °C
Ps = signal power
PN = noise power