The Software Radio subject introduces the student to the principles that allow the implementation of radio transmitters and receivers using digital processing techniques, establishing a bridge between the theoretical foundations of communications and their materialization in flexible and reconfigurable architectures. The course covers the essential concepts of digital and communication systems, the role of A/D and D/A converters, and the operation of specialized devices—such as ASICs, DDC/DUCs, and DSP processors—that are involved in software-defined radio systems. This basis allows us to understand how the performance of each block is characterized and how complete architectures are synthesized based on functional requirements. The course also provides a practical vision of the analysis of real architectures and the process of selecting devices available on the market, which prepares the student to face current and future designs in the field of digital radio.
Titular Professors
Professors
- From digital signal processing, sampled systems theory and its frequency domain representation, decimation interpolation and digital filtering.
- From Electronic circuit design, A/D and D/A converters theory.
- From Computers architecture, computer theory, segmentation, input/output interface, interrupt based programming.
- From Radio technologies, radio performance characterization: sensibility, dynamic range and blocking.
The purpose of the course is for the student to understand the fundamental techniques of digital signal processing applied to the design of radio transmitters and receivers, and to know the operation, performance and limitations of the devices that are part of a digital radio architecture. It also seeks to develop the ability of students to synthesize and analyze complete software-defined radio architectures, relating their components to the established functional requirements. In the same way, it aims for the student to acquire the ability to identify and select real devices available on the market that fit the specifications of a design, and to be able to adapt said design when technological or availability conditions require it.
1. Introduction
1.1. Introduction to digital systems
1.2. Introduction to communication systems
1.3. Analog filters
2. A/D and D/A converters
2.1. The ideal A/D converter
2.2. The real A/D converter
2.3. The D/A converter
3. ASIC in the field of radio
3.1. The DDC / RSP
3.2. The DUC / TSP
4. DSP processors
4.1. Concepts of finite precision arithmetic
A. Theoretical sessions
B. Exercises to solve at home.
D. Participation to virtual forums.
E. Teamwork in the practice sessions. The students design algorithms and implement it in real platforms. They collaborate to achieve the best solution. When the work is finished, they make an oral presentation of his results to the teacher and the rest of the students. They also give a written document to the teacher summarizing the work and conclusions.
The evaluation of the subject consists of two very different parts that must be approved separately:
- Theory (70% of the final grade)
- Practical (30% of the final grade)
- The student's ability to correctly describe the operation, features and limitations of the digital and analogue devices that are part of a transceiver, including converters, ASICs and DSP processors, is assessed.
- The competence to combine analogue and digital blocks within a Software Radio architecture is assessed, justifying the connections, dependencies and implications in the overall behaviour of the system.
- The student's ability to derive a digital radio architecture from functional requirements, select the appropriate blocks and propose a technically coherent and justifiable solution is considered.
- The ability to identify the main blocks, interpret their behaviour, evaluate their performance and relate them to the concepts of signal processing and communications studied in the theory is assessed.
- The quality of the practical project is evaluated, including the correct implementation of the design or simulation, the justification of design decisions, the analysis of the results obtained, the ability to adapt the design to the availability of real devices, and the clarity of the final presentation (written or oral).
The subject provides the student with notes.
'Integrated A/D and D/A converters', Rudy van de Plassche, Ed. Kluwer, © 1994. Very complete text that is very useful to complete the characterization part of A/D and D/A converters.
'AD6644 Datasheet', Analog Devices, www.analog.com. Datasheet of one of the most technologically advanced A/D converters: 65 MSPS - 14 bits.
'AD9754 Datasheet', Analog Devices, www.analog.com. Datasheet of one of the most technologically advanced D/A converters: 125 MSPS - 14 bits.
'AD6620 Datasheet', Analog Devices, www.analog.com. Datasheet of the Digital Down Converter that is used as a reference in the theoretical explanation of the class.
'AD6622 Datasheet', Analog Devices, www.analog.com. Datasheet of the Digital Up Converter that is used as a reference in the theoretical explanation of the class.
'The Scientist and Engineer's Guide to Digital Signal Processing', W. Smith, Analog Devices. Free distribution book on the Internet that deals with various theoretical and practical aspects of Digital Signal Processors. It includes numerous implementations on Analog Devices processors.
'The DSP Handbook', Andrew Bateman, Ed. Prentice-Hall, © 2001. This text is one of the most complete and exhaustive that deals with topics related to Digital Signal Processors.
ADSP-2106x User ?s Manual ?, Analog Devices, www.analog.com. Datasheet of the DSP that is used in class as a practical case and as a basis for carrying out one of the two practices.