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Altera_Forum's avatar
Altera_Forum
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11 years ago

quartus II NCO ip core to get constant voltage for different frequency generated

Hi all,

By using a "cyclone V" "5cgxfc5c6f27c7N" board and quartus II trying to generate sine wave using IP Core ,capable of generating different frequency with constant peak to peak voltage.

In quartus II i used NCO IP core to generate sine wave where i can change the frequency by giving input to "phi_inc_i" input pins ,i connected R2R ladder DAC to convert it to analog.

I get sine wave according to "phi_inc_i" value , but i am not able to get constant Peak to Peak voltage ,as i increase the output frequency Pk-Pk votage decreases.

please help me how to mentain constant pk-pk voltage for all different frequencies.

1 Reply

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

    That is expected and is due to sinc envelope. Either accept it or precorrect(inverse sinc filter) or adjust scaling of nco output for each frequency.