The DSPF_dp_biquad function results differ from the Matlab results - what does it mean?

Andrew Mikitenko

The spru657c "TMS320C67x DSP Library Programmer’s Reference Guide" says that "The DSPF_dp_biquad function results differ from the Matlab results".

What does this mean? Who does it in wrong way - Dsp Library or Mathlab?

Is it still possible to use the DSP Library DSPF_dp_biquad function and get correct results?

over 13 years ago

0 Sach over 13 years ago

Prodigy 70 points

Hi Andrew,

I am going through the same mystery. Though my coefficients match between Matlab and on target (C6713 DSK), the filter characteristics don't match. I have tried using both SP and DP biquad functions from DSPLIB but they both behaved same, at least in my case. What type of filter are you trying to realize? What is your target processor/board?

Regards,

Sach

0 Andrew Mikitenko over 13 years ago in reply to Sach

Prodigy 30 points

Hi, Sach!

Seems nobody in IT nows what is it. ;-(((( ( With DP biquad functions). But they swear that Sp works correctly.

Here is an answer to my email concerning the problem

Thank you for contacting Texas Instruments. Your request has been received and Service Request number 1-700633691 has been assigned to your inquiry.

You might try using the dsp67x_sa.src (non-optimal), to see if you will get same result as Matlab results.

They were several post related to this topic on our e2e forum:

http://e2e.ti.com/support/dsp/tms320c6000_high_performance_dsps/f/112/p/30770/107341.aspx#107341

http://e2e.ti.com/support/dsp/tms320c6000_high_performance_dsps/f/115/t/12368.aspx?PageIndex=2

http://e2e.ti.com/support/dsp/tms320c6000_high_performance_dsps/f/115/p/12368/470170.aspx#470170

Regards, Andrew

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The DSPF_dp_biquad function results differ from the Matlab results - what does it mean?