Types of RF Dynamic Range
| Type | Definition | Typical System Value |
|---|---|---|
| Linear DR | P1dB − MDS (Minimum Detectable Signal) | 70–90 dB |
| SFDR (Spurious-Free) | Range where IM3 < noise floor | 60–80 dB |
| Instantaneous DR | Largest/smallest detectable signal simultaneously | 50–70 dB |
SFDR Formula
SFDR = (2/3) · (IIP3 − Noise_Floor) [referenced to input] where Noise_Floor (dBm) = −174 + NF + 10·log₁₀(BW) Example: IIP3=−5 dBm, NF=5 dB, BW=10 MHz: Noise_Floor = −174 + 5 + 70 = −99 dBm SFDR = (2/3) · (−5 − (−99)) = (2/3) · 94 = 62.7 dB This means: you can receive two signals with 62.7 dB difference before IM3 of the stronger signal masks the weaker signal.
1 dB Compression Dynamic Range
DR_1dB = P1dB − MDS P1dB (input): typically −10 to 0 dBm for LNA MDS = Noise_Floor = −174 + NF + 10·log₁₀(BW) At 10 MHz BW, NF=5 dB: MDS = −99 dBm DR_1dB = (−10) − (−99) = 89 dB This means: LNA handles signals from −99 dBm to −10 dBm before compression causes gain saturation.
RF View Dynamic Range Analysis: Analyze LNA gain (S21), NF, and port match from .s2p files. Use the NF Cascade Calculator for system noise floor. Combine with bench P1dB and IIP3 to compute complete dynamic range. Free on Android.