Understanding Signal Gain and Log Energy
Signal gain explains how much a signal changes between two points. It can describe a power change, voltage change, current change, or stored energy change. Linear ratios are useful in raw calculations. Log ratios are easier for large ranges.
Why Log Energy Matters
Many physics signals span tiny and huge values. A microphone output can be small. A radio transmitter output can be large. Log energy compresses that range. It also makes repeated gain stages easier to add. A ten decibel rise means a tenfold power increase. A three decibel rise is almost double power.
Power, Voltage, Current, and Samples
The calculator supports common measurement paths. Power mode uses direct input and output power. Energy mode compares direct energy values. Voltage mode converts voltage into power through impedance. Current mode uses the load resistance. Sample mode estimates signal energy from squared samples. This works well for pulses, recorded waves, and digital signals.
Reading The Results
The gain ratio shows linear change. A value above one means gain. A value below one means loss. Decibels show the same change on a log scale. Positive decibels mean amplification. Negative decibels mean attenuation. Zero decibels means no net change.
Practical Use
Use consistent units before entering values. Keep impedance realistic for the circuit. Use the same duration for both paths. For sampled signals, use equal sample spacing. Select voltage samples when samples are voltage values. Select current samples when samples are current values. Use dimensionless samples for normalized signal work.
Design Notes
Log energy helps compare sensors, filters, amplifiers, antennas, and audio chains. It can show weak losses that raw numbers hide. It can also show unsafe gain before hardware testing. Always confirm calculated results with real measurements. Components can heat, saturate, clip, or drift. Good calculations still need careful lab judgment.
Common Mistakes
Do not mix peak voltage with RMS voltage. Use one convention across both sides. Do not enter zero for input energy. Log gain needs a positive ratio. Do not compare unlike signals without scaling. A sampled pressure wave and voltage wave have different meaning. Review the chosen mode before exporting results. Small entry errors can create large decibel changes. Use notes carefully afterward.