PCM1789: PCM1789 phase problem

switch

Part Number: PCM1789

Hi ，

PCM1789 replace AKM4388，We found that the phase of the high-pitched and low-pitched AUX channel of the PCM1789 prototype is basically the same, while the phase of the high-pitched and low-pitched BT channel is quite different.The figure is shown below.What parameters need to be set to affect the delay and phase in PCM1789?

over 3 years ago

0 switch over 3 years ago

Expert 2375 points

Supplement：The phase difference between PCM1789 and AKM4358 AUX is not significant, as shown in the figure below

0 switch over 3 years ago

Expert 2375 points

Supplement：The phase difference between PCM1789 and AKM4358 AUX is not significant, as shown in the figure below

0 Paul_Frost over 3 years ago in reply to switch

TI__Guru 52663 points

Hi Smith,

Are you using the same I2S sample rates for both outputs? Could there be some hardware output differences between the two?

Thanks,

Paul

0 switch over 3 years ago in reply to Paul_Frost

Expert 2375 points

Hi Paul，

Both Sampling mode = Auto，The hardware is pretty much the same。

0 switch over 3 years ago in reply to Paul_Frost

Expert 2375 points

Hi Paul，Does the register setting affect it?

0 Paul_Frost over 3 years ago in reply to switch

TI__Guru 52663 points

Hi Smith,

The register settings should not affect this. Do you have any output filtering? The phase response almost looks like the there is a low pass filter at ~3kHz. Is the amplitude vs frequency response the same?

Thanks,

Paul

0 switch over 3 years ago in reply to Paul_Frost

Expert 2375 points

Hi Paul，

Below is a schematic of PCM1789 and AKM4358

PCM1789

AKM4358

0 Paul_Frost over 3 years ago in reply to switch

TI__Guru 52663 points

Hi Smith,

Is the amplitude vs frequency response the same?

I see there is a simple low-pass filter on the output (1kΩ, 820pF||820pF), but is there any additional load on the output?

Thanks,

Paul

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PCM1789: PCM1789 phase problem