DSP project problem - Page 1
Forum section: electronics / projects

author: strikefreedom
author_rank: Newbie
timestamp: March 31, 2012, 06:11:50 am
content: I need to design a AM-SSB using code composer studio and C6713The AM coding is under the rulph chassing dsp book , problem is how to make it to SSBCan anyone help meplease

author: Bored@Work
author_rank: Super Contributor
timestamp: March 31, 2012, 10:09:20 am
content: When is your homework due?

author: vk6zgo
author_rank: Super Contributor
timestamp: March 31, 2012, 01:27:34 pm
content: Normally SSB is produced by first producing a Double Sideband supressed carrier signal (DSB) rather than an AM (Double Sideband full carrier signal).One sideband of the DSB signal is then suppressed,either with a hardware filter,or with a phase cancellation process.In your case,the DSP processor could substitute for either process.I can't quote the mathematical expressions for any of these forms of modulation off the top of my head,but if you search the 'Net you will find them, & you can probably then configure your DSP process to produce these expressions in real signal form.

author: strikefreedom
author_rank: Newbie
timestamp: March 31, 2012, 02:47:34 pm
content: the due date is before 13 aprilI search all the related net but still not idea , i try to edit the coding and put the filter coding but there have error ...so need some assist to solve ...Thank.

author: ejeffrey
author_rank: Super Contributor
timestamp: March 31, 2012, 08:00:30 pm
content: Give us something here. Lots of people will be happy to help you with your homework, but try to show that you are interested in the answer (rather than interested in having someone do your homework for you) and that you have thought about the problem. Start by explaining what you know about the difference between AM, DSB suppressed carrier, and SSB. Explain what parts you don't understand, and what you have tried that hasn't worked.

author: strikefreedom
author_rank: Newbie
timestamp: April 01, 2012, 02:52:12 am
content: This is my main codingAM-double sideband suppressed carrierand i need to add the filter method to extract one of the two sidebands.//AM.c#include "DSK6713_AIC23.h" //codec-dsk support fileUint32 fs=DSK6713_AIC23_FREQ_8KHZ; //set sampling rateshort amp = 1; //index for modulationvoid main(){short baseband={1000,951,809,587,309,0,-309,-587,-809,-951,-1000,-951,-809,-587,-309,0,309,587,809,951}; //400-Hz basebandshort carrier ={1000,0,-1000,0,1000,0,-1000,0,1000,0,-1000,0,1000,0,-1000,0,1000,0,-1000,0}; //2-kHz carriershort output;short k;comm_poll(); //init DSK, codec, McBSPwhile(1) //infinite loop{for (k=0; k<20; k++){output=((amp*baseband*carrier/10)>>12);output_sample(20*output); //scale output}}}Below this is filter coding , but it cannot add simply like that. i try it before much time and edit , but there have error -(expected a declaration , exppected an expression) and i not familiar in coding.so need some help or assists or some answer... ( include file ).interrupt void c_int11() //ISR{short i;dly = input_sample(); //new input @ beginning of bufferyn = 0; //initialize filter's outputfor (i = 0; i< N; i++)yn += (h* dly); //y(n) += h(i)* x(n-i)for (i = N-1; i > 0; i--) //starting @ end of bufferdly= dly[i-1]; //update delays with data moveoutput_sample(yn >> 15); //scale output filterreturn;}void main(){comm_intr(); //init DSK, codec, McBSPwhile(1); //infinite loop}