neoflash
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Mixed-Signal Designer
Posts: 397
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Hi,
Hope can have some synthesizer experts to comment on this question.
Some reference and many recent approaches show that it is getting popular to do phase error correction in fractional synthesizers.
Furthermore, people are re-quantizing the PEC correction DAC so that there is no need for a very fine DAC.
The re-quantization of the PEC residue inside synthesizer is usually done by a sigma-delta modulator.
As shown in the figure, the requantization modulator is usually working at the same clock rate of the first modulator. As we know, the modulator is usually working on the input which changes much slower than the clock rate. However, in this setup, the 2nd modulator is working on the input signal which changes in significant step every clock cycle, is there any issue with it?
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