DSP Debugging

Abstract

• Software debugging tools: tailored to needs of programmers and software developers
• Poor support for DSP algorithm analysis and implementation
• Makeshift solution: manual code instrumentation and external post-processing

Proposal:

Extension of software debuggers with algorithm analysis capabilities (as provided, e.g., by Matlab)

Motivation: DSP Algorithm Development

Debugging Concept

• Non-intrusive algorithm analysis and data access
• Data transfer and mapping of data structures
• Data sampling for statistical analyses
• Conditional breakpoints based on derived parameters
• Full Matlab functionality in debugger: data analysis, visualization, ...

GNU Debugger with Matlab

• Different interpreter backends, e.g., Matlab and GNU Octave
• New GDB commands, e.g., mbreak, mshell, mcmd, ...
• Data from debug target can be requested by the interpreter using special syntax, e.g., plot(gdb::x@2048)
• Additional tool: Automatic generation of GDB scripts from inline debug statements

Eclipse with Matlab

• Communication with Matlab via dedicated control process
• Integrated Matlab console for direct Matlab interaction
• Extended breakpoint capabilities:
  
  • data transfer from debug target to Matlab
  • hooks for m-scripts (init, sample, finalize)
  • breakpoint condition in Matlab syntax

Example Use Cases

1. OFDM Transmission
   
   • Evaluation and visualization of channel statistics, peak to average power ratio (PAPR), and signal space constellation
   • Break if PAPR limit is exceeded
2. Audio / Speech Coding
   
   • e.g., Adaptive Multi-Rate Codec [ETSI GSM 06.90]
   • Evaluation of spectral envelope quantization
   • Computation of log-spectral distortion
   • Histogram collection
   • Break if log spectral distortion exceeds 5 dB, i.e., lsd(A, Aq) > 5

Contact

Bernd Geiser <geiser@ind.rwth-aachen.de>
Institute of Communication Systems and Data Processing (IND)

Stefan Kraemer <kraemer@iss.rwth-aachen>
Institute for Integrated Signal Processing Systems (ISS)

Project Page at sourceforge.net

http://gdb-ili.sourceforge.net