EISNOVA
Emulation Interface using Symbolic Neural Object for Visualization and Analysis
Visual System C provides a set of library that could be used to model a wide variety of communication system. The library includes important mathematical operators, signal generators, filters and many other signal processing blocks. Intermediate results can be inspected by collecting them using Signal Collection block.
In this example, the library set is used to model a QAM communication system that includes a 64 QAM transmitter, a complex noise channel and a 64 QAM receiver. The transmit data is generated by a random integer generator which is mapped to the QAM constellation using a table represented by a Complex Constant Vector block. The table is indexed by the Get Element block. The QAM signal is upsample to two times the Nyquist rate and filtered by the a Root Raised Cosine Filter defined by the General Digital Filter block. Complex Noise is added to the filter output which is filtered by a second Root Raised Cosine Filter at the front end of the receiver. The filtered signal is downsampled to Nyquist rate. The received data is inferred by finding a the closest constellation point on the constellation table.
There is a Top Parameter block that reads a parameter file "top_params.txt" that provides the top level configuration of the system. By changing the field "qam_type", different QAM can be modeled.
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