Minimum detectable signal

In general it is clear that for a receiver to "see" a signal it has to be greater than the noise floor. To actually detect the signal however, it is often required to be at a power level greater than the noise floor by an amount that is dependent on the type of detection used as well as other factors. There are exceptions to this requirement but coverage of these cases is outside the scope of this article. This required difference in power levels of the signal and the noise floor is known as the signal to noise ratio (SNR). To establish the minimum detectable signal (MDS) of a receiver we require several factors to be known.