What is Amplitude Modulation (AM)?

Amplitude Modulation (AM) is a communication technique used in electronic signaling, most commonly for transmitting information via a radio carrier wave. In AM, the amplitude (signal strength) of the carrier wave is varied in proportion to that of the message signal, such as an audio signal. This calculator helps you determine the key parameters used in RF engineering and telecommunications studies.

The AM Modulation Index Formula

The modulation index (m) is a measure of the extent to which the carrier signal's amplitude is varied. It is calculated using the formula:

m = Am / Ac

Where:

• Am: Peak amplitude of the modulating (message) signal.
• Ac: Peak amplitude of the carrier signal.

How to Use This Calculator

To use the AM modulation calculator with steps, simply follow these instructions:

1. Enter the Message Signal Amplitude (Am).
2. Enter the Carrier Signal Amplitude (Ac).
3. (Optional) Enter the Carrier Power to calculate total transmitted power.
4. Click "Calculate" to see the modulation index, percentage, and step-by-step derivation.

Frequently Asked Questions

What is 100% modulation?

100% modulation occurs when the message amplitude equals the carrier amplitude (m = 1). If the message amplitude exceeds the carrier amplitude (m > 1), it is called over-modulation, which leads to signal distortion and envelope collapse.

Why is the modulation index important?

The modulation index determines the quality and efficiency of the transmitted signal. A low index results in a poor signal-to-noise ratio, while over-modulation creates interference in adjacent channels.