Aim

To perform the Cross Correlation of two given discrete sequence in TMS320C6745 KIT.

Requirements

☞CCS v4

☞TMS320C6745 KIT

☞USB Cable

☞5V Adapter

Theory

In signal processing, cross-correlation is a measure of similarity of two waveforms as a function of a time-lag applied to one of them.The cross-correlation is similar in nature to the convolution of two functions.

In signal processing, cross-correlation is a measure of similarity of two waveforms as a function of a time-lag applied to one of them. This is also known as a sliding dot product or sliding inner-product. It is commonly used for searching a long-duration signal for a shorter, known feature. It also has applications in pattern recognition, single particle analysis, electron tomographic averaging, cryptanalysis, and neurophysiology.

For continuous functions, f and g, the cross-correlation is defined as’:

where f * denotes the complex conjugate of f.

Similarly, for discrete functions, the cross-correlation is defined as:

The cross-correlation is similar in nature to the convolution of two functions.

In an autocorrelation, which is the cross-correlation of a signal with itself, there will always be a peak at a lag of zero unless the signal is a trivial zero signal.

Procedure to build a project on Cross Correlation using TMS320C6745 DSP

1. Open Code Composer Studio v4 .

2. In WorkSpace Launcher.

☞BROWSE → Select the project location and make one new folder, MAKE NEW FOLDER → Type the Workspace name, OK → OK.

3. FILE ⇒ NEW ⇒ CCS PROJECT

☞Project name: Type your project name.

☞Tick use default location. → NEXT

☞Project type C6000.

☞Tick Debug And Release. → NEXT → NEXT.

☞Output type: Executable.

☞Device Variant : generic – TMS320C6745.

☞Device Endianness : little

☞Code Generation Tools: TI v6.1.12.

☞Run time support library: automatic.

☞Target content: none. →FINISH

4.FILE ⇒ NEW ⇒ SOURCE FILE

☞Source file: Type your projectname.c( .c extension is must ).

☞Type the program.

☞FILE → SAVE.

5. Paste the following board library files in workspace location.

☞Common folder (contains header files)

☞Gel folder (contains gel file)

☞Library folder(contains library files)

6. Paste the Linker file in the project location.(linker file is available in cd)

Note: Those folders and linker file are availble at cd.

7. PROJECT ⇒ PROPERTIES ⇒ C/C++ BUILD → BASIC OPTION

☞Target processor version(–silicon version, -mv)    :   6400+ OK.

☞IN C/C++ BUILD, → INCLUDE OPTIONS (Add dir to #include search path(–include_path,-I)) select this add icon  and add the following three path by indivdually    –  “${Diag}../../common/header”    –  “${XDAIS_CG_ROOT}/packages/ti/xdais”    –  “${C6000_CSL_CG_ROOT}/include”

8. FILE ⇒ NEW ⇒ TARGET CONFIGURATION FILE

☞file name: projectname. ccxml (.ccxml extension is must)

☞Connection: Texas Instrument XDS100 v1 USB Emulator.

☞Device: TMS320C6745. (Tick the TMS320C6745)→ SAVE → TARTGET CONFIGURATION → C674X_0 → BROWSE, browse the workspace location, open the gel folder and select the GEL file. → OPEN → SAVE.

9. In C/C++ Project window, Right click the project ⇒ REBUILD PROJECT.

10. Connections

☞Connect the usb cable, PC to TMS320C6745 KIT.

☞Connect the 5v adapter.

☞Power on the kit.

11. TARGET ⇒ DEBUG ACTIVE PROJECT.

12. VIEW ⇒ MEMORY

13. In right side, memory window will open. Type the address and give the input at particular location.

Give the input as follow:

X(n)

0xC0001000 – 00000001

0xC0001004 – 00000002

0xC0001008 – 00000003

0xC000100C – 00000004

14. TARGET ⇒ RUN.

15. TARGET ⇒ HALT.

See the Output at Particular location:

0xC0001050 – 00000004

0xC0001054 – 00000012

0xC0001058 – 00000020

0xC000105C – 00000030

0xC0001060 – 00000020

0xC0001064 – 00000012

0xC0001068 – 00000004

Program for Cross Correlation using TMS320C6745 DSP

#define xn 4

#define hn 4

void main()

{

        int *xval,*hval,*outval,*temp,j;

        int n,k,i;

 

        xval = (int *)0xc0001000;

        hval = (int *)0xc0001030;

        outval = (int *)0xc0001050;

        temp = (int *)0xc0001070;

 

        for(i=0;i<(xn+hn-1);i++)

        {

                temp[i]=0;

                outval[i] = 0;

                xval[xn+i]=0;

                hval[hn+i]=0;

        }

 

        for(i=0,j=(hn-1);i<(hn);i++,j--) // making x2n(n-L)

                temp[j] = hval[i];

 

        for(n=0;n<(xn+hn-1);n++)

        {

                for(k=0;k<=n;k++)

                        outval[n] = (outval[n])+((xval[k])*(temp[n-k]));

        }

Result

Thus, the Cross Correlation of two given discrete sequence has performed and the result is stored at memory location (0xC0001050).