📜  调频和调相的区别

📅  最后修改于: 2021-09-16 10:49:35             🧑  作者: Mango

先决条件 – 调制

1. 频率调制:
频率调制是一种调制,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。

2. 相位调制:
相位调制是一种调制,其中载波的相位根据调制信号的瞬时幅度变化,保持幅度和频率恒定。 Phase Modulation 和Frequency Modulation 类似,但在Phase Modulation 中,载波信号的频率没有增加。相位调制用于移动系统。修改载波的相位以发送数据或信息。调频和调相的区别:

S.NO. Frequency Modulation Phase Modulation
1. In Frequency Modulation amplitude and phase remain the same. In Phase Modulation, the frequency and amplitude remain the same. 
2. Frequency Modulation is proportional to modulating voltage. Phase Modulation is proportional to modulating voltage.
3. Associated with the change in frequency, there is some phase change. Associated with the change in phase, there is some frequency change.
4. It is possible to receive FM on a PM receiver. It is possible to receive PM on a FM receiver.
5. Noise immunity is poor than AM and PM. Noise immunity is better than AM but worst than PM.
6. Signal to noise ratio is better than in phase modulation. Signal to noise ratio is poor than in frequency modulation.
7. Frequency Modulation is widely used. Phase Modulation is used in mobile system.
8. In FM, the frequency derivation is proportional to the modulating voltage only. In PM, the frequency derivation is proportional to the modulating voltage as well as modulating frequency.
9. Amplitude of FM wave is constant. Amplitude of PM wave is also constant.
10. In FM, received signal is of high quality. In PM, received signal is of low quality.