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How to convert dBFS scale to dBc

Yoonsun Kim
Expert 1870 points

I am confused by different unit when comparing ADCs,

If one datasheet says that SFDR is 92 dBFS at -1 dBFS, 100  dBFS at -2 dBFS, how can  I convert it to dBc scale?

If SFDR is 97 dBc at -1 dBFS, how can I convert it to dBFS scale?

  • 0
    TI__Genius 17470 points

    Hi Yoonsun,

    SFDR[dBc] = PSIG[dBFS] + SFDR[dBFS]

    SFDR[dBFS] = SFDR[dBc] - PSIG[dBFS]

    Where SFDR is defined as a positive number and PSIG is the signal level defined as a negative number.

    -1 dBFS + 92 dBFS = 91 dBc

    -2 dBFS + 100 dBFS = 98 dBc

    97 dBc - (-1 dBFS) = 98 dBFS

    Regards,
    Matt Guibord