ground Problem

Hi, 

i am trying to connect a Wi-Fi/Bluetooth module to a DSP and then to amplifiers. 

my problem is that interference frequencies occur when I connect the Wi-Fi module to the same battery the rest is connected to. 

this is necessary because I am building a portable loudspeaker. 

does anyone have an idea how to get rid of these interference frequencies?

 

I have amplifiers and the DSP connected to signal ground.

Thanks in advance,

Wim

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  • i  have drawn a sketch of my circuit. 

    I hope it helps.

  • also my amp board connect the signalGND and the normal GND is this normal?

  • 0
    •  Analog Employees 
    on Jul 13, 2020 8:46 PM 2 months ago in reply to Wim.h

    Hello Wim.h

    This is really difficult to troubleshoot remotely. The diagrams help to some extent but there are a few details I am not certain of. 

    How I approach things like this is to study where the currents have to flow. So the power for the Wi-Fi module, where does it have to flow between ground and power? Does it share the same paths as the analog audio? The grounds should be tied all together but as close to the power source as possible so they all have their own path to ground and do not share the same wires/traces for very long. 

    Also, keep in mind that the current path between power and ground will setup a magnetic field. So make sure they are not coupling if possible. 

    Then when it comes to the Wi-Fi/Bluetooth module. It obviously has an antenna. The placement of this antenna will also be important. Keep it away from the audio. 

    What will be difficult is this mock up of eval boards to prove the concept. With wires and long lines it makes all this more difficult. So the final design should be better. 

    Well, these are my first thoughts on this. If anyone else reading this has experience with this please chime in. 

    Dave T

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  • 0
    •  Analog Employees 
    on Jul 13, 2020 8:46 PM 2 months ago in reply to Wim.h

    Hello Wim.h

    This is really difficult to troubleshoot remotely. The diagrams help to some extent but there are a few details I am not certain of. 

    How I approach things like this is to study where the currents have to flow. So the power for the Wi-Fi module, where does it have to flow between ground and power? Does it share the same paths as the analog audio? The grounds should be tied all together but as close to the power source as possible so they all have their own path to ground and do not share the same wires/traces for very long. 

    Also, keep in mind that the current path between power and ground will setup a magnetic field. So make sure they are not coupling if possible. 

    Then when it comes to the Wi-Fi/Bluetooth module. It obviously has an antenna. The placement of this antenna will also be important. Keep it away from the audio. 

    What will be difficult is this mock up of eval boards to prove the concept. With wires and long lines it makes all this more difficult. So the final design should be better. 

    Well, these are my first thoughts on this. If anyone else reading this has experience with this please chime in. 

    Dave T

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