Final answer:
The first conversion in a dual-conversion superheterodyne receiver aims at image frequency rejection and initial signal selection, while the second conversion improves selectivity and sensitivity. Demodulation and frequency amplification are separate processes that occur after these conversions.
Step-by-step explanation:
In a dual-conversion superheterodyne receiver, the aims of the first and second conversions are critical for its proper functioning. The first conversion primarily focuses on image frequency rejection and the initial selection of the desired signal. This step converts the incoming RF (radio frequency) signal to a first IF (intermediate frequency), which is chosen to maximize image rejection and to make the filtering of unwanted signals easier. The second conversion then aims to improve the selectivity and sensitivity of the receiver by converting the first IF to a second, often lower, IF which can be more finely filtered and amplified without as much concern for image frequencies.
Frequency amplification and demodulation are separate processes typically occurring after the second IF stage. The demodulation is the process where the carrier wave is processed to extract the original audio or data signal. Amplitude modulation (AM) and frequency modulation (FM) are examples of how the carrier wave can be modified to carry information.