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Attenuator Basics
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Attenuator Basics
r1 r2
Zin o---/\/\/\---o---/\/\/\----o Zout
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/ r3
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GND
r3= 2*sqrt(Zin * Zout * A)/ A - 1
r1= Zin((A+1)/(A-1)) - r3
r2= Zout((A+1)/(A-1)) - r3
Where
Zin (input impedance) 50ohms
Zout(output impedance) 50ohms
A (Attenuation, numerical ratio of input to output power) = whatever
Say you want to cut your power in half, A would be equal to .5
Plug the values into the equation and wala' you've got an attenuator.
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