Noise in Angle Modulation System

Angle modulation systems, such as frequency modulation (FM) and phase modulation (PM), are also susceptible to various types of noise that can degrade the quality of the received signal. The most common types of noise in angle modulation systems are thermal noise, intermodulation distortion, and phase noise.

1. Thermal noise: As mentioned earlier, thermal noise is generated by the random motion of electrons in a  conductor at a finite temperature. In angle modulation systems, thermal noise is present in the receiver components such as amplifiers and mixers, and it can degrade the quality of the received signal.

2.Intermodulation distortion: Intermodulation distortion (IMD) is a type of distortion that occurs when two or more signals are mixed in a nonlinear device. In angle modulation systems, IMD can be caused by nonlinearities in the receiver components such as mixers, amplifiers, and filters. IMD can create unwanted signals that interfere with the received signal and degrade its quality.

3. Phase noise: Phase noise is a type of noise that is present in oscillators and can cause fluctuations in the phase of the carrier signal. In angle modulation systems, phase noise can cause distortion in the received signal, especially if the receiver is sensitive to phase noise.

To minimize the effect of noise and distortion in angle modulation systems, various techniques such as filtering, equalization, and modulation schemes can be used. For example, using a high-Q filter can help minimize the effect of thermal noise by rejecting unwanted signals. Using a low noise amplifier (LNA) at the beginning of the receiver chain can help amplify the received signal and minimize the effect of thermal noise. Additionally, using a high-quality carrier recovery circuit with low phase noise can help extract the carrier signal and improve the receiver's overall performance.

Like AM, noise performance of angle modulated systems is characterized by parameter γ