Minimum detectable signal calculator – receiver sensitivity calculator

Minimum detectable signal calculator – receiver sensitivity calculator

This calculator estimates the minimum detectable signal, also called the noise floor of a receiver. It helps determine the smallest signal power a system can capture above thermal noise, based on noise figure, temperature and bandwidth.

Useful for RF engineers, receiver designers and technicians who want to optimize the sensitivity of a communications system.

dB

Formula

MDS = 10 × log10((k × T) / 1mW) + NF + 10 × log10(BW)

Explanation of the formula

  • k is the Boltzmann constant (−228.6 dBW/(K·Hz)), representing the fundamental thermal noise.
  • T is the temperature in Kelvin, generally set at 290 K.
  • NF is the receiver noise figure in decibels (dB).
  • BW is the system bandwidth, expressed in Hz, MHz or GHz.
  • The MDS result is obtained in dBm and indicates the lower detection limit of the useful signal.

Example: calculation of MDS for 10 MHz of bandwidth

Input : NF = 5 dB, BW = 10 MHz, T = 290 K

Output : MDS ≈ -129 dBm

Benefits and uses

  • Evaluates the sensitivity of RF receivers.
  • Allows you to optimize the performance of communication systems.
  • Helps compare different receivers based on their internal noise.
  • Essential for designing long distance radio links and low noise equipment.