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Altera_Forum
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11 years ago

Confirmation about sine wave equation of NCO IP Core

I tried plotting the following sine wave equation from page 3-1 of NCO IP Core User Guide v14.1 into an excel file. s(nT) = Asin[2π(fO+ fFM)nT+ ϕPM+ ϕDITH)] I also generated...
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Altera_Forum
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11 years ago

Section 3-1 defines N as the "magnitude precision," and with that definition it is more or less correct if you consider that magnitude is separate from the sign. An M-bit 2's complement sample has a maximum range of -2^N - +(2^N)-1, where N is M-1. However the UG is not entirely consistent because later on the value M refers to all bits of the output, including sign, and they still call it "magnitude precision."

The take-away is that the core will give you a full-amplitude signal, no bits are wasted, so you have to use a bit of thought and not take the UG too literally.

My $0.02 anyway.

-Fred