What are the maximum modulation limits for an AM station?

The maximum modulation limits for an AM (Amplitude Modulation) station are defined to ensure proper operation and to minimize interference with other signals. When AM modulation occurs, the audio signal modifies the amplitude of the carrier wave, and this modulation is often expressed as a percentage of the carrier amplitude.

In the context of these limits, the accepted maximum is that the positive peaks can reach up to 125% of the carrier amplitude. This allows for some headroom in the modulation, which can accommodate the dynamic range of audio signals that may peak above the carrier level without causing overmodulation distortion. On the other hand, while the positive peaks can exceed 100%, the negative peaks are typically limited to 100%. This cap on negative modulation helps to maintain signal integrity and reduces the risk of distortion that could result from negative peaks exceeding the carrier level.

Therefore, the correct choice reflects these modulation standards by allowing for 125% positive peaks while keeping negative peaks capped at 100%. This understanding is crucial for ensuring that AM stations operate within safe parameters, avoiding interference with adjacent channels and maintaining audio quality.