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Altera_Forum's avatar
Altera_Forum
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14 years ago

How to expand the output of cordic algorithm

Hi,

I'm going to ues cordic alglrithm in verilog to calulate the sin and arcsin

in the IQ modulation and demodulation .

The input phase range is [ 0 , 2*pi ] of cordic in the TX . And I have to

recover the phase information , so I want to use cordic to calulate arcsin .

But we know the output range of arcsin is [ -2/pi , +2/pi ] . Who can tell

me how to expand the output range of arcsin .

Spectrum

2 Replies

  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    14 years ago

    Search for papers on CORDIC, e.g. Ray Andraka has an in-depth paper on it.

  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    14 years ago

    Output range of arcsin isn't a CORDIC problem, I think. It's about the principal value interval of the function. See http://en.wikipedia.org/wiki/arcsin

    You can extend the range periodically, but I guess this doesn't solve your problem. You need to choose a demodulation algorithm with unambiguous phase result.