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Altera_Forum
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16 years ago

NCO : phase modulation

Hi, I'm trying to build a qpsk modulator with the nco megacore. I don't understand how to set the value of φPM. φPM=P/(2**Pwidth). But is it in radian, in degree ? My example : ...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
16 years ago

To my opinion, the scaling of P is obvious from the IP manual equations. The range is always a full cycle. If you understand P as signed quantity, the represented range is +/- pi. You have to specify Pwidth, which isn't listed in your example, but I guess it's default 16 Bit. Then you have 0x7fff / 0x8000 respresenting +/- pi.