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) }
dBi
dBm
dBc
{ 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 }_{ [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) }
\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) }
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
