Sensitivity in a receiver is normally taken as the minimum input signal (Smin) required to produce a specified output signal having a specified signal-to-noise (S/N) ratio and is defined as the minimum signal-to-noise ratio times the mean noise power, | RECEIVER SENSITIVITY NOISE RECEIVER SENSITIVITY Sensitivity in a receiver is normally taken as the minimum input signal Smin required to produce a specified output signal having a specified signal-to-noise S N ratio and is defined as the minimum signal-to-noise ratio times the mean noise power see equation 1 . For a signal impinging on the antenna system level sensitivity is known as minimum operational sensitivity MOS see equation 2 . Since MOS includes antenna gain it may be expressed in dBLi dB referenced to a linear isotropic antenna . When specifying the sensitivity of receivers intended to intercept and process pulse signals the minimum pulse width at which the specified sensitivity applies must also be stated. See the discussion of postdetection bandwidth Bv in Section 5-2 for significance of minimum pulsewidth in the receiver design. Smin S N minkToB NF receiver sensitivity black box performance parameter 1 or MOS S N minkToB NF G system sensitivity . the receiver is connected to an antenna 2 transmission line loss included with antenna gain where S Nmin Minimum signal-to-noise ratio needed to process vice just detect a signal NF Noise figure factor k Boltzmann s Constant x 10-23 Joule K To Absolute temperature of the receiver input Kelvin 290 K B Receiver Bandwidth Hz G Antenna system gain We have a lower MOS if temperature bandwidth NF or S Nmin decreases or if antenna gain increases. For radar missile and EW receivers sensitivity is usually stated in dBm. For communications and commercial broadcasting receivers sensitivity is usually stated in micro-volts or dBpv. See Section 4-1. There is no standard definition of sensitivity level. The term minimum operational sensitivity MOS can be used in place of Smin at the system level where aircraft installation characteristics are included. The black box term minimum detectable signal MDS is often used for Smin but can cause confusion because a receiver may be able to detect a signal but not properly .
