This calculator estimates the minimum detectable signal (MDS) of a receiver, also called the noise floor. It takes into account system noise figure, temperature and bandwidth to determine the lowest level of signal that a receiver can distinguish from noise.
Formula
MDS = 10 × log10( (k × T) / (1 mW) ) + NF + 10 × log10(BW)
Constants
- k = Boltzmann constant = −228.6 dBW/(K Hz)
- T = temperature in Kelvin (default value 290 K)
- NF = noise factor in dB
- BW = bandwidth in Hz, MHz or GHz
- MDS result in dBm
Explanation of the formula
The MDS calculation combines the thermal noise generated by the ambient temperature with the system noise figure. The higher the noise figure or bandwidth, the more the noise floor increases, limiting the receiver’s ability to detect weak signals.
Uses of the calculator
- Evaluate the sensitivity of an RF receiver or communications system.
- Design low-noise systems for radar or satellite applications.
- Compare the performance of different receivers under similar conditions.
- Tool to help optimize the detection of weak signals.