When a radiotelephone transmitter is 100% modulated by a sinusoidal waveform, what is the expected change in antenna current?

When a radiotelephone transmitter is 100% modulated by a sinusoidal waveform, what is the expected change in antenna current?

• A. 22.5% increase
• B. 22.5% decrease
• C. 12.25% increase
• D. No change in antenna current

Answer: (A)

When a radiotelephone transmitter is 100% modulated by a sinusoidal waveform, the expected change in antenna current is a 22.5% increase. This is related to the way amplitude modulation works relative to the carrier wave. In amplitude modulation (AM), the amplitude of the carrier wave is varied in accordance with the amplitude of the input signal (the sinusoidal waveform in this case). When modulation occurs, the power of the transmitted signal increases due to the additional information being carried by the sidebands produced alongside the carrier frequency. Specifically, for 100% modulation, the additional sidebands contribute to higher power output, which is reflected in an increase in the antenna current. The 22.5% increase specifically comes from calculations related to the power levels in an AM system. The relationship between carrier power, modulation index, and the increase in current can be derived from the formula for calculating power in the presence of modulation. Essentially, at 100% modulation, the power increases by a factor that translates into a measurable increase in the current flowing through the antenna. Therefore, when a transmitter operates at full modulation, the antenna must draw more current to deliver this additional energy, resulting in the stated increase. This fundamental aspect of modulation and its

When a radiotelephone transmitter is 100% modulated by a sinusoidal waveform, the expected change in antenna current is a 22.5% increase. This is related to the way amplitude modulation works relative to the carrier wave.

In amplitude modulation (AM), the amplitude of the carrier wave is varied in accordance with the amplitude of the input signal (the sinusoidal waveform in this case). When modulation occurs, the power of the transmitted signal increases due to the additional information being carried by the sidebands produced alongside the carrier frequency. Specifically, for 100% modulation, the additional sidebands contribute to higher power output, which is reflected in an increase in the antenna current.

The 22.5% increase specifically comes from calculations related to the power levels in an AM system. The relationship between carrier power, modulation index, and the increase in current can be derived from the formula for calculating power in the presence of modulation. Essentially, at 100% modulation, the power increases by a factor that translates into a measurable increase in the current flowing through the antenna.

Therefore, when a transmitter operates at full modulation, the antenna must draw more current to deliver this additional energy, resulting in the stated increase. This fundamental aspect of modulation and its