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Signature 1000 - How to know the instrument noise?

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    Ellie Best

    Dear Van,

    Apologies for the late response! The measurement uncertainty can be found in the header of the .ad2cp file in the line beginning with GETPRECISION. The precision/uncertainty is in cm/s, and is provided for horizontal, vertical, and beam velocities (more info in the AD2CP Integrators Guide). The instrument noise can be found either on the Final Test Checklist that is included in the instrument box when it is sent to you from Nortek, or you can measure it by taking some measurements in air (in a location free of external noise) and reading off the amplitude measurements - these will usually be ~30 dB.

    Best regards,

    Ellie

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    Van Nguyen

    Dear Ellie, 
    I am very thankful for your answer. However, because I do not directly communicate with the Signature data by the AD2CP file, I used the processed files from the Signature software in .mat format instead. My problem now is I do not know the "noise floor" of the Signature 1000 to subtract from the velocity spectra. I would like to ask if there is any easier way for me to find out the "Noise floor" from .mat files or from any other manuals. Thank you so much. I hope to get the responses soon from you or any kind person could help. 

    Sincerely yours,

    Van

    Source of the video: https://www.youtube.com/watch?v=_WyTY4N7IvY

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    Ellie Best

    Hi Van, it's not possible to find the noise floor just from the .mat files, but if you send your instrument serial number to support@nortekgroup.com I will be able to find this out for you.

    Best regards,

    Ellie

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