filter stereo audio

Go To Last Post
5 posts / 0 new
Author
Message
#1
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Hello,

I need to take an audio input (coming from an audio jack), apply a IIR filter and output the audio to a headset.
The input needs to be sampled at 44kHz, 16 bits, stereo.

What is the best hardware to achieve this?
(I am aware of VLSI VS1053 chip, but here in this project I am interested in using AMTEL instead of VS1053)

How can I do it (without using VS1053)?

Best regards,
David

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

The AVR32 can do the filter and audio output (ABDAC) but you need an external ADC if you want good quality audio.

There are some IIR filters etc in the avr32 software framework:

http://www.atmel.com/dyn/resourc...

http://www.atmel.com/dyn/resourc...

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

We are running a standard Codec using the SPI port, configured for 16bits data, and using a pdca channel to store the samples directly in internal memory.

We are sampling 16-bit stereo, so it should not be a problem. :-)

But for your app. you could probertly do something like this:

Configure SPI interrupt to trigger on SPI rx complete.

SPI_ISR_Data_Ready(..)
{
  data = read_adc();
  out = iir(data);
  write_dac(out);
}

So every sample is feed into the iir filter, and the output is written to codec dac.

Hope that makes sence...

Jakob Justesen
MaJust ApS
www.majust.dk

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Waw, thanks for the replies!
What chip do you suggest for the ADC (maybe VLSI 1053b, or TI TLV320AIC3204)?
Is there an evaluation kit with an AVR32 chip, a ADC chip, and a stereo input and output connectors?

Thanks,
David

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Sorry for the late reply.

Hmm. I don't know the Codec's you mention, but looking at the TI webpage, I would probertly go for: TLV320AIC23B, since it has build-in Headset amplifier and Line-in interface with Programmable Amplifier.

That should save you some components. :-)

Jakob Justesen
MaJust ApS
www.majust.dk