The June 2026 edition of the UK Practical Wireless magazine has a nice writeup of FreeDV RADE including diagrams of the architecture.

One of the aims of the Free-DV project has been to create an open-source digital voice system with comparable or better performance than the closed-source systems that dominate current commercial and amateur digital voice products.
At the heart of their latest development is the use of neural networks. Neural networks attempt to emulate the way the human brain learns.

Thanks Practical Wireless UK.