Hello,
I am working with Wheatstone and they are using the PCM4201. They have used this device in a the 96K sample mode in the past but their latest design is running at 48K samples. Their description of the problem is as follows.
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What I think I see is that the serial audio port appears to be clipping at half the amplitude (i.e differential p-p amplitude of 2.5 volts rather than 5.0 volts.)
The device supposedly works in 3 modes and I see this problem in normal speed low power. If I float the RATE pin for normal speed high performance, I get no serial bits toggling, and strangely the RATE pin itself is bouncing around.
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I am working to get a schematic to but from looking through the datasheet I do not see anything that would indicate that the lower sample rate would have this issue versus the higher rate. The dynamic range of both rates is the same so I do not think it is clipping based on the signal resolution.
I do not think that it is a supply issue since the rail requirements are rather straight forward.
There are no programmable gains in the device would result in this sort of signal distortion.
I will work to gain more information about the system but I wanted to get the ball rolling toward finding an answer for why a change in sample rate would result in such different operation.