Photo AI
Figure 4 shows a block (subsystem) diagram for a radio communication system - AQA - A-Level Physics - Question 3 - 2018 - Paper 8
Question 3
Figure 4 shows a block (subsystem) diagram for a radio communication system. Figure 4 information input (eg voice) input transducer modulator transmitting aer... show full transcript
Worked Solution & Example Answer:Figure 4 shows a block (subsystem) diagram for a radio communication system - AQA - A-Level Physics - Question 3 - 2018 - Paper 8
Step 1
Step 2
Step 3
Explain why the signal strength at stage D is weak.
Answer
The signal strength at stage D is weak primarily due to:
- Attenuation of electromagnetic waves across the transmission path, where the signal diminishes over distance.
- Reflection and absorption effects from surrounding structures and materials, which cause further loss of energy.
Step 4
Complete the graph in Figure 5 to represent the combined amplitude modulated (AM) signal.
Answer
In the graph, the combined AM signal will show a wave pattern that represents the modulating sine wave altering the amplitude of the carrier wave, effectively forming an envelope around the carrier signal.
Step 5
Suggest whether all these stations can broadcast hi-fi music using the full audio frequency of 20 kHz.
Answer
Not all stations can broadcast hi-fi music using the full audio frequency of 20 kHz. The allocated frequency range of 540 kHz to 1600 kHz limits the bandwidth for each station. Broadcasting capacity is generally around 4 kHz per station, which is insufficient to carry a full range of 20 kHz required for hi-fi audio, making it impossible for all to broadcast at that fidelity.