Enter your system's Bandwidth, Noise Figure, Temperature, and required Signal-to-Noise Ratio (SNR) into the Minimum Detectable Signal Calculator to find your Minimum Detectable Signal (MDS), along with Thermal Noise Power and Sensitivity — the weakest signal your receiver can reliably pull out of the noise.
Minimum Detectable Signal (MDS)
--
Thermal Noise Power
--
Sensitivity
--
MDS is the lowest power level of a signal that can be detected by a receiver above the background noise. It represents the sensitivity threshold of the receiver system.
Larger bandwidth increases thermal noise power, which reduces sensitivity (higher MDS). Narrower bandwidth improves sensitivity by reducing the noise floor.
Higher noise figure degrades receiver sensitivity, resulting in a higher (worse) MDS value. A 1 dB increase in noise figure directly increases MDS by 1 dB.
Temperature affects thermal noise power. Higher temperatures increase thermal noise, which degrades sensitivity and increases MDS. Standard calculations use 290K (room temperature).
Typical SNR requirements: analog voice (10-12 dB), digital data (6-10 dB), radar detection (13-15 dB). Higher SNR provides better signal quality but requires stronger signals.
Better sensitivity (lower MDS) allows detection of weaker signals, extending communication range. A 3 dB improvement in MDS roughly doubles the communication range.
MDS is typically expressed in dBm (decibels relative to 1 milliwatt). Lower dBm values indicate better sensitivity (ability to detect weaker signals).
MDS can be improved by reducing noise figure (better LNA), narrowing bandwidth, cooling the system, or using external low-noise amplifiers at the antenna.