ELEMENTARY,
MY DEAR WATSON



AKA: SDRI fifth meetup!

JULY 2016

Software Defined Radio Israel

MAIN PRINCIPLE OF DECIBELS

{ Ratio }_{ [dB-reference] }=10\cdot \log _{ 10 }{ \left( \frac { { Value }_{ [base] } }{ Reference_{ [base] } } \right) }
Ratio[dBreference]=10log10(Value[base]Reference[base]){ Ratio }_{ [dB-reference] }=10\cdot \log _{ 10 }{ \left( \frac { { Value }_{ [base] } }{ Reference_{ [base] } } \right) }

dBi

dBm

dBc

{ Ratio }_{ [dBm] }=10\cdot \log _{ 10 }{ \left( \frac { { Value }_{ [mW] } }{ 1_{ [mW] } } \right) }
Ratio[dBm]=10log10(Value[mW]1[mW]){ Ratio }_{ [dBm] }=10\cdot \log _{ 10 }{ \left( \frac { { Value }_{ [mW] } }{ 1_{ [mW] } } \right) }
{ Ratio }_{ [dBc] }=10\cdot \log _{ 10 }{ \left( \frac { frequency\_ component\_ power }{ Carrier\_ power } \right) }
Ratio[dBc]=10log10(frequency_component_powerCarrier_power){ Ratio }_{ [dBc] }=10\cdot \log _{ 10 }{ \left( \frac { frequency\_ component\_ power }{ Carrier\_ power } \right) }
{ Ratio }_{ [dBi] }=10\cdot \log _{ 10 }{ \left( \frac { Gain }{ Gain-isotropic\_ antenna } \right) }
Ratio[dBi]=10log10(GainGainisotropic_antenna){ Ratio }_{ [dBi] }=10\cdot \log _{ 10 }{ \left( \frac { Gain }{ Gain-isotropic\_ antenna } \right) }

CHEAT-SHEET

DECIMAL DB
1 0
2 3
10 10
A\cdot B\Longleftrightarrow \log _{ x }{ \left( A \right) + } \log _{ x }{ \left( B \right) }
ABlogx(A)+logx(B)A\cdot B\Longleftrightarrow \log _{ x }{ \left( A \right) + } \log _{ x }{ \left( B \right) }
\frac { A }{ B } \Longleftrightarrow \log _{ x }{ \left( A \right) - } \log _{ x }{ \left( B \right) }
ABlogx(A)logx(B)\frac { A }{ B } \Longleftrightarrow \log _{ x }{ \left( A \right) - } \log _{ x }{ \left( B \right) }
\log _{ x }{ \left( { A }^{ B } \right) =B\cdot } \log _{ x }{ \left( A \right) }
logx(AB)=Blogx(A)\log _{ x }{ \left( { A }^{ B } \right) =B\cdot } \log _{ x }{ \left( A \right) }

MULTIPLIERS

WHAT IS NOISE?

EVERYTHING THAT IS NOT YOUR SIGNAL

NOISE AND INTERFERENCES CAN:

 

​- MAKE THE TASK OF DECODING A SIGNAL (MUCH) MORE  

  DIFFICULT

 

- REDUCE THE QUALITY OF A RECEIVED SIGNAL

 

- (IN EXTREME CASES) DAMAGE YOUR EQUIPMENT

 

POTENTIAL SOURCES

NATURE - THERMAL NOISE, MATHEMATICAL LIMITATIONS

 

DIFFERENT SIGNALS

 

UNCHARTED \ WRONG USAGE OF COMPONENTS (SPEC, MATCHING)

 

COMBINATION OF ALL THE ABOVE :-)

spur

Link
budget

Elementary, My dear Watson

By raziele

Elementary, My dear Watson

SDRI third meetup

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