1. 调幅：
它是一种调制，其中载波的幅度根据调制信号的瞬时幅度而变化，保持相位和频率不变。修改载波的幅度以发送数据或信息。它可以远距离传输，具有很大的范围。它的调制指数从 0 到 1 不等。在幅度调制中，频率和相位保持不变。
2. 频率调制：
它是一种调制，其中载波的频率根据调制信号的瞬时幅度而变化，保持相位和幅度不变。修改载波的频率以发送数据或信息。它不能长距离传输，范围更小。它的调制指数总是大于一。在频率调制中幅度和相位保持不变。
调幅和调频的区别：
| Amplitude Modulation | Frequency Modulation |
|---|---|
| In amplitude modulation, the frequency and phase remain the same. | In frequency modulation amplitude and phase remain the same. |
| Its modulation index varies from 0 to 1. | Its modulation index is always greater than one. |
| It has only two sidebands. | It has an infinite number of sidebands. |
| It has simple circuit. | It has complex circuit. |
| The amplitude of the carrier wave is modified in order to send the data or information. | The frequency of the carrier wave is modified in order to send the data or information. |
| It requires low bandwidth in the range of 10 kHz. | It requires high bandwidth in the range of 200 kHz. |
| In AM received signal is of low quality. | In FM received signal is of high quality. |
| It works in a frequency range of 535 to 1705 Kilohertz (KHz). | It works in a frequency range of 88 to 108 Megahertz (MHz). |
| It operates in the medium frequency (MF) and high frequency (HF). | It operates in the very high frequency. |
| It has poor sound quality. | It has better sound quality. |