it 327 - schweber chap 31 men and women who turn their lives over to god will discover that he can...
TRANSCRIPT
IT 327 - Schweber Chap 3 1
Thought of the DayMen and women who turn their lives over to God will
discover that He can make a lot more out of their lives than they can. He will: 1. deepen their joys,2. expand their vision, 3. quicken their minds,4. strengthen their muscles, 5. lift their spirits, 6. multiply their blessings,7. increase their opportunities,8. comfort their souls, 9. raise up friends, 10.and pour out peace.
Whosoever will lose his life in the service of God will find he has eternal life.
- Pres. Ezra Taft Benson
IT 327 - Schweber Chap 3 4
DeciBels
• Origin of the unit?
• Why?
For Power: dB = 10 log10 (P2/P1) For Voltage: dB = 20 log10 (V2/V1)
OR: For Power: dB = 10 log10 (Pout/Pin) For Voltage: dB = 20 log10 (VMeas/VRef)
Example 1: Perfect wire (R = 0Ω; L = 0H; C = 0F)
P1 = 1W; P2 = 1W. Find dB.
IT 327 - Schweber Chap 3 5
DeciBels: More Examples
P1 = 1W; P2 = 0.5W. Find dB.
V1 = 10V; V2 = 5V. Find dB.
P1 = 50W; P2 = 0.1aW. Find dB.
Voyager 1 & 2
P1 = 1W; P2 = 1000W. Find dB.
Commercial power amplifier
P1 = 50kW; P2 = 10µW. Find dB.
Commercial AM radio (KSL 1160)
IT 327 - Schweber Chap 3 6
DeciBels: Standard References
dBW = 1 W How much is 20 dBW?
dBm = 1 mW How much is -30 dBm?
dBV = 1 V How much is 40 dBV?
dBmV = 1 mV How much is -120 dBmV?
dBc = ideal carrier
dBi = isotropic (omnidirectional)
dB (audio) = ? How much is 30 dB? 70 dB? 100 dB? 120 dB?