Limiter shows weird behaviour after Reset in ADAU1452

Hi,

i am using a limiter in an ADAU1452 hardware project. After every reset of the adau1452 and loading of the dsp programm and parameter the limiter starts with <-70dB gain and then slowly over several minutes runs up to 0 dB gain. This happens even for small input signals.

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It shows that the behaviour is dependant of the decay value.

The higher the value the slower the gain moves up.

This can be reproduced with the evalboard,

Unfortunatly i don't arrive to share the project here, so i only have a screenshot.

My SigmaStudio version is 4.6

Can anyone reproduce this behavior?

And can anyone explain it?

  • Maybe the explanation is that the Decay unit is not dB/s but ms or at least a time.

    The lower the decay the higher is the distortion.

    So decay 8 fits about 10ms and decay 23 about 10 000ms.

    Now i found one remark in the help: 

    Larger values result in longer decays, with 23 never recovering to the original gain.

    Butvi also find the formula:

    Decay dB/s Value stored in RAM = (fs / 26373 * Decay), where “Decay” is the value entered in the block.

    Seems to be some discrepancy between the two definitions in the help.