When ADC oversample and decimation, the DC and slow-moving cann't benefit,to slove the problem adding a bandlimit noise, this noise can be using linear serial feedback registers to do, but I have no paper about this(linear serial feedback ....), can you help me, or give me some advice? thanks

some question:
1) The dither noise is ramdom, and the fs/2k<f<fs/2, at last the noise can be filter by low pass filter, why limit the noise ampplitude between -0.5LSB and +0.5LSB!