Class CD PWM Amplifiers — Lesson - 3

This lesson covers the concept of Class D, and CD amplifiers. It discusses the performance, efficiency and limitations of these amplifiers. The lesson also touches upon Pulse Width Modulation (PWM) and its role in Class D amplifiers. It then delves into the concept of linearity, discussing the challenges and solutions to achieve linearity in power amplifiers. A detailed explanation on Feedback as a Linearization technique is provided, which can be applied to improve the performance of these amplifiers. The lesson concludes with a brief discussion on Polar Feedback and its potential applications.

Video Highlights

07:20 - Class D amplifier
17:43 - Current waveforms and fundamental component
28:42 - Lineairty and adjacent channel power rejection (ACPR)
46:28 - Modified architecture of system and analog subtraction
53:04 - Error vector magnitude

Key Takeaways

- Class A, B, C, D, AB and CD amplifiers have different characteristics and efficiencies, making them suitable for different applications.
- Pulse Width Modulation (PWM) is employed in Class D amplifiers, making them efficient but also introducing harmonic distortions.
- Linearity is a crucial aspect in power amplifiers, especially in modern wireless systems. Achieving perfect linearity can be challenging.
- Feedback as a Linearization technique can be used to improve the performance of power amplifiers. Feedback ensures that the output is linearly related to the input, thus reducing distortion.
- Polar Feedback is an alternative approach to improving amplifier performance. However, it requires careful design and implementation to be effective.