AD7768 Dynamic Range vs. SNR

Please explain why is the Dynamic Range specification of AD7768 is less than the SNR (signal to noise ratio) ?

How are each of these specs being calculated/tested...?

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  • +1
    •  Analog Employees 
    on Jul 27, 2021 5:03 AM

    Hi, 

    I think the test conditions answered this question. The two setup is different in terms of the digital filter used and the type of input. They are both calculated based from the concept of a ratio of the rms of the input to the rms value of the noise.

    The noise using Sinc5 is better than the noise in wideband filter, thus it has higher specification.

    The SNR uses a 1KHz, -0.5dB FS input and measured as the ratio of the input signal to the rms sum of all other spectral components (FFT)

    While the Dynamic range uses the rms Full scale input range to the rms shorted input noise.  

    Thanks,

    Jellenie

Reply
  • +1
    •  Analog Employees 
    on Jul 27, 2021 5:03 AM

    Hi, 

    I think the test conditions answered this question. The two setup is different in terms of the digital filter used and the type of input. They are both calculated based from the concept of a ratio of the rms of the input to the rms value of the noise.

    The noise using Sinc5 is better than the noise in wideband filter, thus it has higher specification.

    The SNR uses a 1KHz, -0.5dB FS input and measured as the ratio of the input signal to the rms sum of all other spectral components (FFT)

    While the Dynamic range uses the rms Full scale input range to the rms shorted input noise.  

    Thanks,

    Jellenie

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