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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. **0 3.1 -** State the letter representing the subsystem in which you might find an indu... 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 due to several factors:
- Attenuation of the electromagnetic wave as it travels through the transmission path leads to a decrease in signal strength.
- A small fraction of the radiated energy is directed towards the receiver, as much of it is lost in natural topography and absorption in the atmosphere.
Step 4
Complete the graph in Figure 5 to represent the combined amplitude modulated (AM) signal.
Answer
The combined AM signal graph should show modulation where the amplitude of the radio carrier signal varies according to the envelope shaped by the modulating sine wave, typically representing the information signal.
Step 5
Suggest whether all these stations can broadcast hi-fi music using the full audio frequency of 20 kHz.
Answer
Given that the frequency spectrum allocated is from 540 kHz to 1600 kHz, it is not possible for all these stations to broadcast hi-fi music at the full audio frequency of 20 kHz. This is because each AM station typically requires bandwidth for its signal and cannot accommodate the full audio frequency due to limitations in the modulation and channel spacing.