phase shift of TMDSDSK6713

Baptiste Crettaz,

Welcome to the TI E2E forum. I hope you will find many good answers here and in the TI.com documents and in the TI Wiki Pages. Be sure to search those for helpful information and to browse for the questions others may have asked on similar topics.

The DSK 6713 is very popular at universities for a variety of applications. There are newer processors that run faster and may even cost less, but if you have a DSK 6713 in hand, it is a great tool to use.

My recommendation is that you look for application notes for the C6713. Go to TMS320C6713B and click on Technical Documents. There will be a few Application Notes listed, and a link to more of them below that box. Look through all the titles to see what might be applicable to your project, even if they do not talk about active noise control in particular.

You will have to define your terms to know what your answer is for phase delay. The minimum phase delay would be one sample period, so that would depend on the sampling rate of your application, usually from 8KHz to 96KHz, but it could easily be outside that range depending on your specifications and requirements.

The method you use to do your calculations will also affect phase delay. If you do all of your processing between the time one input is sampled from the ADC and the time the next output is required at the DAC, then you would achieve the 1 sample phase delay. That is unlikely.

You should search the TI Wiki Pages for "C6000 workshops" (no quotes) and especially look through the material of the C6x1x one.

Regards,
RandyP

If you need more help, please reply back. If this answers the question, please click  Verify Answer  , below.

Hello!

Thank you for your answer. I'm sorry, but I've still a doubt: if I look at the datasheet of the TLV320AIC32B that does the conversion on the TMDSDSK6713, I see page 3-20 some information about different group delays according to the filter in use. Is it still possible to achieve the process within 1 sample period, or did I miss something? Is there a possibility to bypass this filter?

If it is not the case, do you have any board that can perform DSP, and that owns a codec without any delay (except the sample time, of course)?

Thank you for your help, best regards,

Baptiste C.

Baptiste,

Your doubt is very reasonable. I do not know the AIC32 well enough to address the question of disabling an internal filter. You should ask that specific part of the question on the Audio Converters Forum where there will be experts on that device.

My answer was based only on the point of view of the C6713. My apologies for not knowing about the AIC32 for your help.

Regards,
RandyP

Hello Navaneeth,

Yes, we finally found the solution for this project.  Actually every sigma-delta converter includes a digital filter which will add a fixed delay to the operation. Since our application was related to control, we decided to use SAR converters that allows a 1-sample delay. We finally didn't realize it with a C6713 but with a C28346 (Delfino), but it doesn't change anything for this phase-shift issue.

So if your project is related to control, it might be useful to consider using a SAR. The latest versions of Delphino controllers include a 16 bit SAR (like the F28377), which makes them very interesting for noise or vibration control applications.

But if your system doesn't have these highly real-time requirements, a sigma-delta as the one on the starter kit of the C6713 can be perfect ;-).

Good luck!