Sensitivity:- The ability to amplify the weak signals is called sensitivity. It is the function of overall receiver gain. Sensitivity of radio receiver is decided by the gain of the RF IF amplifiers. The sensitivity is expressed in microvolt or millivolt.
Selectivity:- It is the ability of radio receiver to reject the unwanted signals. Selectivity depends on IF amplifier. Higher the Q of the tuned circuits better is the selectivity. It is used to distinguish between two adjacent carrier frequencies. Selectivity curve shows the how perfectly the receiver is able to select the desired carrier frequency and reject other frequencies.