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General >> Tech Talk >> audio playback quality requirements in SLIMbus/digital filter requirements
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Message started by vivkr on Jul 18^th, 2008, 7:38am

Title: audio playback quality requirements in SLIMbus/digital filter requirements
Post by vivkr on Jul 18^th, 2008, 7:38am

Hi All,

I was looking through the specs for SLIMbus from MIPI and there is some mention of CD-quality playback. I was wondering if the audio playback quality is expected to be as good as normal CD, or portable CD players, or worse, since this is an interface for mobile phone applications. I don't know if the quality of ordinary headphones is that good.

Based on the above, there would be restrictions on the kind of digital filter one can use in the ADC chain. I assume that IIR filters are out due to phase distortion, and one can only use FIR. Am I right in supposing this or is it still ok to have IIR?

Any comments are welcome.

Regards
Vivek

Title: Re: audio playback quality requirements in SLIMbus/digital filter requirements
Post by KDB on Sep 12^th, 2008, 11:47am

Hi,

The provisions of SLIMbus allow LPCM data to be transported at a number of different bit widths and sample rates. Therefore, it is possible to have some "standard" 44.1KHz, 16 bit digital audio being transported, which is what is often referred to as CD Quality. But higher and lower sample rates can also be transported, as well as bit widths up to 32 bits.

Therefore, and DAC or codec filters would have to be tailored for what rates and bit widths you want to support, and the ability to adjust depending upon the incoming sample rate/bit width format.

SLIMbus itself does not impose any particular filter characteristics.

KDB