The coefficients and frequency response of the IMR interpolation filter are shown as follows.
IMR Filter Coefficients
Center Tap: 4096 for low pass; -4096 for high pass
First Half: 10,0,-23,0,48,0,-89,0,154,0,-256,0,432,0,-813,0,2588
Figure 1.
RF-DAC IMR Filter Frequency
Response

The following image shows a zoomed plot of the cross region between high and low pass filter modes.
Figure 2. IMR Filter Frequency Response-Zoom
