Does anyone know if/how it is possible to input an 8kHz mono PCM audio signal to the empeg board for resampling/processing & output.

Also whether it is possible to sample the Mic input and output this to somewhere as 8kHz mono PCM audio?

Any ideas? or will I have to do some off-board DA/AD conversion and steal the analogue Aux/Mic signal.

Oli.

Yes, it would be possible to sample the mic input at that bit rate. The mic input was designed for just that kind of thing. That is a perfect application for the mic input.

You will have to write your own software for it, though. Currently none of the built-in software does any recording.

The software's ok, but it's more the hardware I'm interested in...

I need to find a way to output the PCM signal from the Mic off the board without it being played

That, and to get a corresponding 8k PCM stream into the board for output.

Oli.

ahh c'mon just tell us what your trying to do.. sounds very neat and complicated whatever it is

I just looked for some time for the post & couldn't find it, but I remember being told that it's possible to do some re-soldering of the line out on the back of the empeg so that it would output the raw digital stream. Does anyone else remember this post?

-Zeke

Ok... you could read the post in technical about bluetooth, but here it is...

Kim has sucessfully installed a self contained bluetooth module (ericsson) which supports data transfer via a bluetooth mobile phone, enabling him to establish a GPRS / Dial up connection to the internet with his empeg via a bluetooth enabled mobile phone...

The Ericsson module also supports voice transfer, via two 8khz PCM data lines (in & out). If the PCM data from the phone could be input to the empeg's board, and output through the DSP, and the corresponding Mic input to the empeg sampled and output off the board to the bluetooth module, the empeg can be turned into a fully featured, generic bluetooth handsfree kit.

The phone would be controlled via bluetooth's 'Serial port profile' just as if it was connected to a PC via a serial cable. This would allow the empeg to display caller id, and let you choose whether to answer, or reject the call.

The processing of the Mic signal would also allow for programming of echo cancellation and road noise reducation via previously established voice coding standards.

Any thoughts?

Oli.

just one:
That's awesome!!!
I wish bluetooth phones were cheaper and more readily available in the US

The empeg doesn't have any compatible PCM outputs or inputs though, I'm afraid. The sync serial port - about the only place which is even vaguely capable - is used for the mp3 audio!

Hugo

Ok, so... construct a daughter-board, containing the bluetooth module and a DA converter to output analogue speech to the empeg's Aux input.

Then either do the same for the Mic input - taking the analogue signal off the board, AD it and feed it to the bluetooth module. Or....

Hugo - How is the Mic sampled on the empeg board? does it have a dedicated chip, or is it the same one as the Aux? could a PCM stream be taken from the Mic sampler? - This would obviously not allow for any software tuning, but might be ok.

Oli.

It's the same chip as aux in. The chip has no external PCM interface, it just sits on the strongARM's bus.

Hugo

I'm not familiar with the Ericsson module, or the Linux Bluetooth stack being used, but you should be able to send the ACL audio data over the HCI serial interface. You shouldn't need a direct hardware link as long as you can get the PCM input data into the Empeg. - Eric