Questions about EVAL-ADAU1701MINIZ

jbs4hf@mail.mst.edu Question

Oct 20, 2011 00:00

Hello,

I'm using the EVAL-ADAU1701MINIZ for my project. I basically want to connect two microphones to the trs input and have the dsp calculate the time delay between them. Based upon the time delay, I want to output sine waves to a tone-decoder circuit, which will control a dc stepper motor. The purpose of this project is to point the two microphones to a source of sound (someone speaking to the microphones).

My questions are:

1) Is there an inexpensive preamp that anyone could recommend to bring the input microphones to line-level?

2) Does anyone know if there are example programs that I could look up that would help me with this project?

I have programmed microcontrollers before, but I am inexperienced with the Analog Devices DSPs.

Thanks!

Audio Signal Processors

eeprom

SigmaDSP Audio Processors

evaluationboard

audio

adau1701

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ADIApproved Reply

Oct 21, 2011 00:00

Hi,

We have some basic microphone pre-amp evaluation boards available that might be applicable here. One example is the SSM2167 evaluation board. You can find more details about it here: http://www.analog.com/static/imported-files/application_notes/AN-583.pdf

I guess the first step would be to match the microphones to make sure they have the same level in the DSP. An easy way to do this is to flip the phase of the two microphones, place them as closely together as possible, and then play a loud, low frequency tone. In the ADAU1701, you'll then want to subtract the two microphone signals from one another, and play with the gain of each signal until you basically get zero as the output. This means that you have perfect cancellation (i.e. the in-phase mic and out-of-phase mic are outputting the same level). Then, you can swap the phase of the one mic back so that they are back in phase with each other and continue your experiment!

A simpler solution might be to use an ADAU1761 evaluation board, since the ADAU1761 has built-in mic preamps. Even better, the ADAU1781 evaluation board has two microphones built onto the board itself!

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jbs4hf@mail.mst.edu Reply

Oct 25, 2011 00:00

Hello again,

That helps a lot! You see, I already have the EVAL-ADAU1701MINIZ with me. I really need the preamps for the microphones. Would it be possible if I return the EVAL-ADAU1701MINIZ and get an EVAL-ADAU1781Z, since they are the same price? I don't know the return policy for Analog Devices. Would that be difficult?

Also, does Analog Devices have any example programs/applications for their SigmaDSP program?

Thanks!

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ADIApproved Reply

Oct 25, 2011 00:00

We do not really have a return policy in place for evaluation boards, but I will contact you privately and we can arrange a swap.

SigmaStudio's install directory should contain a folder called "Example Schematics" that can get you started with some simple projects. We also have some application notes available on our website with examples, as well as many posts on this forum that can help you out. There are also some FAQs on the forum that contain basic ideas related to SigmaStudio programming, and the SigmaStudio help file itself contains examples of how to use certain algorithms in practice.

If you still can't find an answer there, just post a question here on the forum!

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EZAdministrator Reply

Aug 2, 2018 00:00

This question has been assumed as answered either offline via email or with a multi-part answer. This question has now been closed out. If you have an inquiry related to this topic please post a new question in the applicable product forum.

Thank you,
EZ Admin

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