p3.RF_Math

p3.RF_Math - RF Math 4050-4034050-403-01 Concepts of W Co c...

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Unformatted text preview: RF Math 4050-4034050-403-01 Concepts of W Co c p s o Wireless Networks ss N wo s Logarithm A logarithm is an exponent Common logarithm: 2 based, 10 based and e based N = 10x log10N = log N = x M = ey logeM = ln M = y logab = logcb / logca bxyics 2 Why logarithms? Use a small number to represent a huge number. number log(10100) = 100 log bc log l ab = l ab + l ac log bxyics 3 dB Pin device Pout t bxyics 4 Decibels Pout gain in dB = 10 log P in bxyics 5 Some special dB values dB -20 -10 -6 -3 0 3 6 10 20 Pout/Pin 0.01 0.1 0.2512 0 2512 0.5012 1 1.995 2 3.981 4 10 100 bxyics 6 dB Conversions A signal is 4000 times stronger after an amplifier. What is the g g p gain in dB? bxyics 7 Examples How much dB is equivalent to a 1000 times gain A 26 dB gain is equivalent to how many times gain? bxyics 8 Additive dB Pin 10 dB -3 dB 20 dB -10 dB -3 dB Pout bxyics 9 dBm dBm is the dB value referencing to a 1 mw. It is an absolute power p level. Pout dBm = 10 log 1 mw dBm Pout = l log 10 -1 bxyics 10 Examples 1 mw = ? dBm 1 watts = ? dBm 43 dBm = ? Watts dB W -26 dBm = ? Watts -80 dBm = ? Watts bxyics 11 Exercises 2 mw = ? dBm 2 watts = ? dBm dB 36 dBm = ? Watts 6 dBm = ? Watts W tt -13 dBm = ? Watts A 4 watt signal passes through a 13 dB amplifier. amplifier What is the power of the output signal? A 6 watt signal passes through a signal attenuator and g p g g the output signal is 300 miliwatt. How many dB the attenuator has? bxyics 12 Homework 4 mw = ? dBm 4 watts = ? dBm 39 dBm = ? Watts dB W 9 dBm = ? Watts -16 dBm = ? Watts 0 dBm = ? Watts bxyics 13 ...
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This note was uploaded on 04/21/2008 for the course VNSA 403 taught by Professor Yuan during the Winter '07 term at RIT.

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