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ADAU1772 - Active Noise Reduction?

Question asked by freemanc on Jan 14, 2014
Latest reply on Oct 21, 2016 by freemanc

Hi Guys,


I've had to ditch the use of the ADAU1701 for my application.  Too many issues getting it working and also it appears that the latency from the ADC to DAC will be too large for what I need as the application is Active Noise Reduction for headphones.  The reason for me picking it in the first place was the large amount of DSP blocks it supports in Sigma Studio as I was going to implement a FIR filter that compensates for the amplitude and phase response of the microphone/speaker.  I've done this in the analog domain before, where a microphone in the headset cavity measures incoming noise, applies a filter to the signal and then drives a speaker to provide a 180' phase shift in the sound.  However, doing this in the analog domain is a nightmare and for this particular design I decided to go the DSP route as arbitrary filters can be created.


However, it is proving to have its own can of worms. The next best device seems the ADAU1772 as it has extremely low latency and seems more geared for microphone/speaker driving than the ADAU1701, however, I see it supports very few of the functions in Sigma Studio that the ADAU1701 did.  No FIR filters, no IIR filters, no delays even.  I see on the datasheet it is supposed to be designed for Active Noise Reduction in mind, but I cannot see from the building blocks provided, how on earth this could be implemented?


Any help would be appreciated!


Kind regards