DSP/BIOS and RTDX Using MATLAB, Visual C++, Visual Basic, and LabVIEW - Digital Signal Processing and Applications with the C6713 and C6416 DSK - page 317

FIGURE 9.10. MATLAB's plot of the FFT magnitude of data received from the DSK.
Example 9.6: MATLAB-DSK Interface Using RTDX for
FIR Filter Implementation ( rtdx_matlabFIR )
This example further illustrates RTDX with MATLAB with the implementation
of FIR filters. Figure 9.11 shows the C source program rtdx_matlabFIR.c that
generates an input signal and implements an FIR filter on the DSK. The input
signal consists of the product of random noise and a sine wave from a lookup table.
This generated signal is the input to an FIR filter (see Example 4.1). The output of
the filter is stored in a buffer, the address of which is transferred to MATLAB
through the output RTDX channel. Initially, the implemented filter is a lowpass
FIR filter with a cutoff frequency at 600 Hz. The coefficients of this filter are
in the file LP600.cof . Two other FIR lowpass filter coefficients can also be
selected in this example: LP1500.cof and LP3000.cof. These three sets of coefficients
were used in Example 4.2 (FIR3LP). The address of the specific filter to be imple-
mented is read through the RTDX input channel. All the appropriate support files
for this Example are in the folder rtdx_matlabFIR . The CCS project is already
built.