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What's New for DSP Communications
New products and improved functionality bolster system-level design capability
by Anne Mascarin
The MathWorks Release 12 brings significant improvements to Simulink's capabilities as a system-level design environment for DSP and communications engineers. This release improves the speed and robustness of Simulink for DSP and communications applications, with many new algorithms and blocks.
Frame and matrix support for system-level design
Frame and matrix support are now intrinsic features of Simulink 4.0 and the DSP Blockset 4.0. Frame-based processing operates on consecutive samples of data at once. Most real-time DSP and communications systems operate on frames to achieve a higher rate of throughput. In Simulink 4, you can create models of these systems that map naturally to the implementation model. In addition, simulation speed improvements of frame-based models are up to ten times faster than sample-based models.
Processing frame-based signals has been simplified in Release 12. All relevant blocks in the DSP Blockset now accept and generate frame-based signals. Blocks have intrinsic knowledge of frames, removing the need to explicitly indicate frame options in the dialog box of every block. Instead, you simply indicate (in the dialog box for the model's source block) that the input signal is to be frame-based, and this knowledge propagates with the signal itself.
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Simulink now supports frames and matrices. The Matrix Concatenation block in Simulink is one way to express frame-based data as multichannel frame-based data. |
Simulink can now generate and manage two-dimensional matrices. This new matrix signal ability enables DSP and communications developers to design and simulate frame- or sample-based multichannel systems. Multichannel systems handle data from several different sources (or channels) at the same time. For example, a 6-by-4 matrix can represent multichannel data. The four columns would represent four distinct channels of data, and the row elements would represent the frames: six samples per frame, one frame per channel. The addition of matrix support to Simulink also simplifies the translation of algorithms from MATLAB to Simulink.
Additional system-level design enhancements
Communications systems can contain hundreds of blocks and describe millions of data points. The new Simulink Performance Tools provides four tools that help developers of communications systems simulate their large-scale systems more effectively. The Model Profiler helps to identify bottlenecks in simulation and performance. The Model Differencing Tool highlights differences between models.
A model browser and a graphical debugger simplify model navigation and analysis in Simulink 4. In addition, signal sources and sinks in the DSP Blockset have been combined into fewer blocks to make block selection easier.
Expanded algorithms and system-level design blocks for communications
The Communications Toolbox has been split into two separate products. As of Release 12, the Communications Toolbox contains only MATLAB functions. The Simulink blocks formerly included in the Communications Toolbox now form the basis of a separate product, the Communications Blockset. The Communications Blockset is a collection of libraries for designing and simulating communications systems with Simulink. It incorporates and extends the functionality of the blocks that were included in the Communications Toolbox 1.5, while also including several new blocks.
Modulation libraries in the Communications Blockset have been expanded to include an amplitude modulation library (PAM, QAM), a frequency modulation library (FSK), and a new continuous-phase modulation (CPM) library, including MSK and GMSK. You can model a wider range of communications systems, including digital video broadcasting (DVB) and dual multitone (DMT), with these new libraries. Blocks and libraries for coding, interleaving, and data manipulation are also new in the Communications Blockset.
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New modulation and interleaving libraries in the Communications Blockset are used to help design and simulate a wider range of communications systems including the ETSI EN 300 744 terrestrial digital video broadcasting standard. |
The Communications Toolbox contains new functions for coding and signal generation as well as the Marcum Q function. Eye diagrams and scatter-plot displays have also been enhanced for better usability.
Enhanced DSP algorithmic functionality
MATLAB and Simulink provide an open environment that supports rapid, interactive algorithm development. You can evaluate and explore algorithms with MATLAB Toolboxes and incorporate the results into a Simulink design.
The Filter Design Toolbox, which subsumes and replaces the Quantized Filtering Toolbox, is a MATLAB Toolbox that contains tools for advanced techniques for designing, simulating, and analyzing digital filters . The Filter Design Toolbox extends the capabilities of the Signal Processing Toolbox by adding filter architectures and structures such as the least p-th norm optimal FIR design and the arbitrary group delay IIR method. This enhanced functionality is beneficial to many developers of digital filters with stringent specifications, such as high-speed equalizers in digital-to-analog converters.
You can use the Filter Design Toolbox to design real-world digital filters, and then import the coefficients that you created with the toolbox into Simulink models. You can accomplish this using the DSP Blockset's Filter Realization Wizard and create a custom block diagram filter. The Filter Design Toolbox also provides functions that quantize floating-point filters, and analyze quantization effects, thereby eliminating ad hoc approaches to filter design.
Filter Design and Analysis Tool (FDATool) is a powerful new GUI in the Signal Processing Toolbox. It lets you design filters from scratch and import externally designed filters for further analysis and refinement. This GUI enables design options from the Filter Design Toolbox if it is installed. The combination of Filter Design Toolbox and the FDATool lets you easily and graphically design and analyze conventional or highly specialized filters. 
Available Soon in Early 2001!Links to DSP implementation tools
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Learn more about DSP and communications design or view product literature. www.mathworks.com/applications/dsp_comm/
