PUREPATHCONSOLE: programmable Biquads function of PurePath Console not support sample rate 8000

Bert

Part Number: PUREPATHCONSOLE
Other Parts Discussed in Thread: TAC5111

Tool/software:

I found the programmable Biquads function of PurePath Console only support sample rate 48Khz, 96khz ,192khz , but we use the sample rate 8Khz, How can let PurePath Console support 8khz ? thanks very much

2 months ago

0 Sydney Northcutt 2 months ago

TI__Genius 17960 points

Hello,

Which device app are you using?

Regards,
Sydney Northcutt

0 Bert 2 months ago in reply to Sydney Northcutt

Intellectual 570 points

I use the tac5x1x-q1 app

0 Mir Jeffres 2 months ago in reply to Bert

TI__Genius 12695 points

Hi,

I am looking more into this, however I suspect that the sample rates in the GUI are for ranges of values that the GUI allows rather than a parameter that is necessary for the filters. You can keep the page on 48kHz mode since this has the lowest range of possible frequencies to filter out. I can verify this in the lab later this week.

Best,
Mir

0 Bert 2 months ago in reply to Mir Jeffres

Intellectual 570 points

hi Jeffres

ok, wait your response , additionally I found different sample rate can generate different filter coefficients for N0, N1, N2, D1,
and D2。 below picture is the result

0 Mir Jeffres 2 months ago in reply to Bert

TI__Genius 12695 points

Hi,

Give me another day to test this

-Mir

0 Mir Jeffres 2 months ago in reply to Mir Jeffres

TI__Genius 12695 points

Hi,

I believe the different coefficients make sense for having different sample rates, since the coefficients affect the poles and zeros of the filter which will change based on the sample rate - when the sample rate changes, it is kind of like the size of the unit circle differs. You can read more about how these coefficients are calculated here in this app note: https://www.ti.com/lit/ab/slaaeh6/slaaeh6.pdf

I think the drop down we are seeing for sample rate needs to be updated so it can work for any sample rate. For now, you can calculate your own coefficients and program the filters with the I2C monitor in PPC. TI has a very useful biquad coefficients converter tool which you can access here: https://www.ti.com/tool/COEFFICIENT-CALC

I will bring the drop down issue up to the PPC development team.

Best,
Mir

0 Bert 2 months ago in reply to Mir Jeffres

Intellectual 570 points

hi Jeffres

the tools https://www.ti.com/tool/COEFFICIENT-CALC is not support tac5111, tac5111 require 32 bits filter coefficients for N0, N1, N2, D1, but the tool COEFFICIENT-CALC generate 16 bits filter coefficients .

and the support products from the download page of COEFFICIENT-CALC also not include tac5111

0 Bert 2 months ago in reply to Mir Jeffres

Intellectual 570 points

could you push the PPC development team to support 8k sample rate for tac5111 ASAP ?

+1 Mir Jeffres 2 months ago in reply to Bert

TI__Genius 12695 points

Hi,

Yes - and do you want some help calculating the parameters for your desired filters? Can you give more info about your desired filter, I can help you calculate the parameters manually or provide some code to calculate. The app note I linked has instructions for writing the params and the given equations, let me know which you are using and I can help in parallel here.

EDIT- the TIBQ calculator does let you increase the resolution to 32 bit, if you click the "Coeff" button and then type 32 in the Resolution box. For example, this is the coefficients for the first EQ filter in the list here:

Best,
Mir

Audio

Audio forum

PUREPATHCONSOLE: programmable Biquads function of PurePath Console not support sample rate 8000