I am using a PCM1753 to output control voltages to an instrument - one voltage is DC, the other is 10KHz, and I notice that the filtered output covers only about half the full-scale range (I am still in DC test mode).
The unfiltered output clearly shows a large artifact that is minimal at mid-range, then increases in the positive direction when a positive output is driven, and in the negative direction when the output goes negative. The artifact is about 1 volt in amplitude and is at the sampling frequency.
The range of output is limited by the maximum excursion of this artifact - at full scale data it reaches the maximum level of 2 volts peak, but the filtered voltage never gets higher than about 1 volt less.
The system clock is 12.5MHz and the frame rate is 130.208 KHz (6.25 MHz data clock and 48 bits per frame). We have tried it at twice these frequencies and at 64 data bits per frame (shifting data as 32 bit right justified - at the lsb - and padding the high order 8 bits) Nothing seems to change this behavior. Is it necessary that the system clock be an exact multiple (128 or 192) of the frame rate for the digital filter to operate properly? The response curves do not seem to indicate this.