Peculiar Ground Problem

[avbhki]

Hi

I have a DSP Board which does some audio post synthesis interfaced
though I2S (input and output). When I use pass-through or bypass, I
can head the audio at the output stage. When I remove bypass and
pass it though synthesis stage, I can see audio signals on the output
(after processing) but I am unable to hear audio. I can hear the
audio when I provide a kind of antenna/ground through body on some
places on board (Supply, GND, connectors, etc). Since DSP board has
only digital gnd, I am connected to the power supply and ground of
output stage only.

Thanks
Avinash

 

[John O'Flaherty]

Hi

I have a DSP Board which does some audio post synthesis interfaced
though I2S (input and output). When I use pass-through or bypass, I
can head the audio at the output stage. When I remove bypass and
pass it though synthesis stage, I can see audio signals on the output
(after processing) but I am unable to hear audio. I can hear the
audio when I provide a kind of antenna/ground through body on some
places on board (Supply, GND, connectors, etc). Since DSP board has
only digital gnd, I am connected to the power supply and ground of
output stage only.

What frequency is it sampled at? Is there a low pass filter on the
output?