If you BER Meter, you can easily measure this Frontend. Sensitivity is a measure of Acceptable BER @ Signal Level.
For instance, you define BER as 1.10^-3 then you decrease the Signal Level and when BER reaches/drop down to this level, this will be the Sensitivity at the same time. SNR is also measured with a Modern Spectrum Analyzers.
Besides this, EVM/Constellation Measurement gives also a figure of Sensitivity with Modern Spectrum Analyzers with Digital Demodulating Feature.