ADAU1787 measure the transfer function between speaker to microphone

Hi nehem,

I'm currently working on an example project in SigmaStudio that should assist you in your desired setup. I should be able to send you one with an explanation on the setup process within the next day or two.

If you have any more details you can provide me on this project setup, I should be able to cater towards your needs in the example project.

Thanks,

TM

Hi nehem,

TF_Speaker_to_Microphone.dspproj

I've created an example project in SigmaStudio that takes two single-ended inputs, such as a microphone, and processes an altered signal through the FastDSP core, and the original signal at the ADC to the output. This project routes the 4 channels (2 processed / 2 original signals), out through the Serial Port 0 via the TDM protocol. From here, I used a Level Shifter to bring the 1.8V communication lines of the ADAU1787 up to 3.3V in order to use with the miniDSP USB Streamer that accepts 3.3V 8Ch 24-bit TDM data and plugs into my PC via the USB port on the device.

With the miniDSP USB Streamer plugged into my PC, I used the audio software - Audacity, in order to record audio from the ADAU1787 into my PC. From here, you could use vector programming applications such as MATLAB and/or Python in order to measure the transfer function by using the recorded audio from the processed signal and unprocessed signal. I believe you would take both FFTs of the processed audio and unprocessed audio and divide the processed signal by the unprocessed signal, which would result in the Transfer Function that was generated from the added processing of the ADAU1787.

I hope this gives you a better idea for how you could measure the Transfer Function between the output and input of the ADAU1787. I think the miniDSP USB Streamer would be a useful device for being able to record the audio output from the Serial Port pins of the ADAU1787 and at least get your signals into an audio software program like Audacity. In terms of processing the Input/Output signal to measure the Transfer Function, using a programming language like Python or MATLAB would most likely be your best bet.

Please let me know if this helps answer your question or if you have any follow-up questions.

Thanks,

TM