About ADAU1761 Noise issue

Hello Sun,

This is most likely a signal integrity issue. Can you supply a schematic showing the I2S connections, all the inputs and outputs. Then can you take a scope screenshot of the waveforms?

Then give me more details explaining the format you wish to use and the sample rate etc.

Thanks,

Dave T

Dear Dave,

This is Homer, who created this issue.

Actually, this is a request from a certification lab.

They test a wireless streaming playback, and found there is a noise coming out when play/pause, next/prev, seeking sometimes, not always.

So, I want to know if ADAU1761 can provide any solution to work around this issue.

like when ADAU1761 detected I2S inactive -> active, and start ramp down/up the input signal, to avoid the pop noise issue.

I enclosed the schematic of this project.

Hello Homer,

So I think I understand. There is a time when the I2S signals are invalid or are removed?

So there is not a way to do this using the serial port. In other words, there is no flag for the serial port that tells when the data is good or bad. However, there may be another way to do this. I do not understand their entire application but perhaps they can use the jack-detect pin? It does not look like they are using a digital microphone so that pin is available. If they have something that they plug in when they change devices then this signal can be used to mute the output. This was its intended function.

If they are testing wireless devices then perhaps there is a logic line that will signal when the RF carrier is present or the PLL is locked or something like that. Then use that signal to drive the jack-detect pin.

Dave T

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