If a transmitter with an antenna current of 8 amps is 100% modulated by sinusoidal modulation, what would be the antenna current?

If a transmitter with an antenna current of 8 amps is 100% modulated by sinusoidal modulation, what would be the antenna current?

• A. 9.8 amps
• B. The antenna current will increase by 22.5%
• C. Either A or B
• D. None of the above

Answer: (C)

In this scenario, the transmitter operates with an antenna current of 8 amps at full (100%) modulation using sinusoidal modulation. When modulation occurs, the antenna current is affected by the modulation process, which changes the average power radiated by the transmitter. With 100% sinusoidal modulation, the peak antenna current can be calculated using the formula that relates the unmodulated current to the modulated current. For 100% modulation, the increase in current due to modulation is approximately 1.414 (which is the square root of 2) times the unmodulated level, because the peak envelope power is higher during modulation. Therefore, the total modulated antenna current is calculated as follows: 1. The peak current increases to about 8 amps × 1.414, yielding approximately 11.31 amps. However, this figure reflects peak modulation conditions. 2. In terms of average antenna current under modulation conditions, the increase can be visualized to be about 22.5%, leading to an average current increase from 8 amps to 9.8 amps (which also expresses the peak modulation aspect). The choice indicating that the antenna current could increase to 9.8 amps aligns with this understanding, together with the

In this scenario, the transmitter operates with an antenna current of 8 amps at full (100%) modulation using sinusoidal modulation. When modulation occurs, the antenna current is affected by the modulation process, which changes the average power radiated by the transmitter.

With 100% sinusoidal modulation, the peak antenna current can be calculated using the formula that relates the unmodulated current to the modulated current. For 100% modulation, the increase in current due to modulation is approximately 1.414 (which is the square root of 2) times the unmodulated level, because the peak envelope power is higher during modulation.

Therefore, the total modulated antenna current is calculated as follows:

1. The peak current increases to about 8 amps × 1.414, yielding approximately 11.31 amps. However, this figure reflects peak modulation conditions.

2. In terms of average antenna current under modulation conditions, the increase can be visualized to be about 22.5%, leading to an average current increase from 8 amps to 9.8 amps (which also expresses the peak modulation aspect).

The choice indicating that the antenna current could increase to 9.8 amps aligns with this understanding, together with the