When audio signals are sent over long distances, radio waves are modulated. Suggest a reason why modulation is used.
State a technical advantage and a technical disadvantage of using frequency modulation instead of amplitude modulation.
An audio signal with amplitude $2.0\,\mu\text{V}$ and frequency $4.2\,\text{kHz}$ is to be sent using a carrier wave of amplitude $10.0\,\text{mV}$ and frequency $100\,\text{kHz}$. Either amplitude modulation or frequency modulation may be used. The amplitude modulation rate is $1\,\text{mV}\,\mu\text{V}^{-1}$. The frequency modulation rate is $5\,\text{kHz}\,\mu\text{V}^{-1}$. Complete Table 5.1 to show the maximum and minimum amplitude values and the maximum and minimum frequency values of the modulated wave for each modulation type.
For the amplitude modulated wave in (b), find the bandwidth.