A little overwhelmed....

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brianv
Newbie
Posts: 1
Joined: Tue Nov 29, 2016 5:38 am

A little overwhelmed....

Postby brianv » Tue Nov 29, 2016 5:52 am

I'm a software guy, looking to prototype an array microphone system. This sure looks like a promising place and product to start, but I'm hoping someone can point me in a good direction for prototyping with a path to productizing. Here's my basic requirements:

* 32 channels / microphones, eventually 64 in the product
* very lightweight in the product, don't care for prototyping
* sample rate of 11kHz or better for each microphone
* coherent clock across all microphones, i.e. ideally corresponding samples will be taken at the same time for each microphone
* in a perfect world, dynamically tunable sample rate, to include non-standard rates
* access to each sample by source for custom DSP / beamforming application
* Windows or Linux prototyping / development, with USB interface ideally

Can someone let me know if one of the products here is what I'm looking for, and the best way to get started on this project?

Many thanks...
henk
Respected Member
Posts: 346
Joined: Wed Jan 27, 2016 5:21 pm

Postby henk » Tue Nov 29, 2016 9:16 am

Hi brianv,

Welcome.

The short answer: an XUF216 can provide you with an interface to 32 PDM microphones producing 32 PCM streams at 16 kHz (or faster). An XUF232 device can provide you with 64 PDM microphones and 64 PCM streams.

The former will leave you with four 62.5 MIPS logical cores, the latter with eight. You can use this to implement other algorithms, such as DSP, although in practice for the number of microphones you look at you may want to add another 216 or 232 device to do the heavy lifting DSP. Also keep an eye on the total amount of memory that you require.

The PDM to PCM software downsamples 3.072 MHz PDM to 384 KHz PCM down to 48, 24 or 16 kHz. You can clock all the microphones off a single 3.072 MHz clock. All converters will run synchronously using the same 3.072 MHz clock.

You can put a USB back-end on the whole thing, just make sure that one of the devices is an XU device (that has an embedded USB PHY). You will have to do the maths whether you can run 32 streams over USB.

Tools are cross platform and run on Windows/Linux/Mac; you just need a USB port.

Cheers,
Henk

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