Other Parts Discussed in Thread: PCM2900
As per the previous locked e2e thread, I too am seeing fluctuating THD+N measurements when I pass audio through the PCM2900C (and a PC on the USB side). Measured THD+N ranges from about 0.04% to 0.14%. A THD+N of 0.004% is acceptable for application.
It is strange how the measurements fluctuates over a few seconds (say, 5 seconds or so?). My audio analyzer shows 1Khz and its harmonics in the noise floor if I leave the inputs unconnected, but otherwise looping audio through a PC. I can also see the noise floor bobble up and down. This noise behavious must be fixed before we can release this design to manufacturing.
Any pointers or suggestions would be most appreciated. In particular I would like to know if there was any follow on with the previous PCM2900 THD Fluctuating thread that ended March of 2016.
Thanks!
Fraser.
