Explanation: The LNA, or Low-Noise Amplifier, is a critical component in receiver systems, especially for weak signals like those from amateur radio satellites or distant stations. Its primary function is to provide significant amplification to these faint radio frequency (RF) signals as the very first active stage in the receiver chain. Crucially, it does this *without* introducing a substantial amount of additional electrical noise, thus preserving or improving the signal-to-noise ratio (SNR). This ensures that the weak signal remains discernible against the background noise for subsequent processing. Option B is incorrect because calculating data is a digital processing function, not an analog RF amplification task. Option C is wrong; the entire purpose of a *low-noise* amplifier is to *reduce* the receiver's overall noise figure, thereby improving its sensitivity. Option D describes a type of feedback or a relationship with an LNB (Low-Noise Block downconverter, which often *contains* an LNA), but it is not the primary function of a standalone LNA.