Software Defined Radio Architectures - Part II — Lesson 4

This lesson covers the limitations of transmitter receiver front ends for different architectures. It delves into the limitations of transmitter receiver contents and explains why different architectures work. The lesson also discusses Local Oscillator (LO) leakage, DC Offset, and IQ imbalance, and how these factors affect signal transmission and reception. For instance, it explains how LO leakage can cause distortion in the homodyne structure and how DC Offset can shift the constellation in one direction. The lesson concludes by comparing the pros and cons of superheterodyne and homodyne structures, providing a comprehensive understanding of these radio architectures.

Video Highlights

00:18 - Limitations of transmitter receiver front ends - LO leakage
05:03 - Limitations of transmitter receiver front ends - DC Offset
10:09 - Effects of DC offset
11:24 - Limitations of transmitter receiver front ends - I/Q imbalance
21:30 - Quadrature coefficient
24:30 - Pros and cons of superheterodyne and homodyne structures

Key Takeaways

- Homodyne and heterodyne are two types of software defined radio architectures.
- LO leakage can cause distortion in the homodyne structure.
- DC Offset can shift the constellation in one direction, leading to misinterpretation of symbols and high Bit Error Rate (BER).
- IQ imbalance can affect the accuracy of the received information.
- Superheterodyne and homodyne structures have their own pros and cons, and understanding these can help in designing better architectures.