MATLAB: How is the dithering generated and applied for the NCO (numerically controlled oscillator) block in Signal Processing Blockset 6.5 (R2007a)

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I would like to know how the dithering in the NCO block (Numerically Controlled Oscillator) is being generated and applied.

Best Answer

The NCO dither generation is based on the PN Sequence Generator block in Communications Blockset. More information on the algorithms used in the PN Sequence Generator block is available in the documentation.
The NCO dither generator is based on the 19th order generator polynominal:
 z^19 + z^18 + z^17 + z^14
with an initial state = 1
For example, when we need a 4-bit dither, we generate 4 consecutive bits from the PN sequence generator. On the next sample hit, we use the next 4 generated bits.
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