Lets Express this graphicly

I figure a graph can explain this better. 10 iterations are run through of an input of 5 producing the red waveform. This is then run as a PWL source in simetrix to simulate a bit stream output @ 2MHz sample rate. This output is then filtered by an low pass RC filter with f -3dB = 20KHz. As can be observed the (green) output is the input code (66% full scale) with some modulator noise.
The modulator noise can be reduced by increasing the bits of the modulator (not applicable for creating a switching amp), increasing the oversample ratio (increasing freq sample) or by increasing the order of the modulator. Or any of those in combination.