ADAU145x Sine Tone oscillator dB unit

Hello takumi3952,

Yes, DBFS but for a 24 bit signal.

Now it is not exactly 0dBFS of the full core's dynamic range (32 bit). It is 0dBFS for a 8.24 fixed point number. This way it correlates with the outside 24 bit world. If you take the output of the oscillator set to 0dB and send it directly out of the core it will be a full scale 0DBFS 24 bit signal.

This is also why you can set it for up to +42 dB. It seems like that is a violation of digital theory but it is not. It is simply the 0dB level in the core which is not full scale for the core but is full scale for the outside 24 bit world.

Is this clear? I am not sure if I explained this correctly. It can seem contradictory.

Dave T