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db2mag

Convert decibels (dB) to magnitude

    Description

    example

    y = db2mag(ydb) returns the magnitude measurements, y, that correspond to the decibel (dB) values specified in ydb. The relationship between magnitude and decibels is ydb=20log10(y)

    Examples

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    For this example, generate a 2-by-3-by-4 array of Gaussian random numbers. Assume the numbers are expressed in decibels and compute the corresponding magnitudes.

    rng('default');
    ydb = randn(2,3,4);
    y = db2mag(ydb)
    y = 
    y(:,:,1) =
    
        1.0639    0.7710    1.0374
        1.2351    1.1044    0.8602
    
    
    y(:,:,2) =
    
        0.9513    1.5098    0.8561
        1.0402    1.3755    1.4182
    
    
    y(:,:,3) =
    
        1.0871    1.0858    0.9858
        0.9928    0.9767    1.1871
    
    
    y(:,:,4) =
    
        1.1761    1.0804    1.0861
        1.1772    0.8702    1.2065
    
    

    Use the definition to check the calculation.

    chck = 10.^(ydb/20)
    chck = 
    chck(:,:,1) =
    
        1.0639    0.7710    1.0374
        1.2351    1.1044    0.8602
    
    
    chck(:,:,2) =
    
        0.9513    1.5098    0.8561
        1.0402    1.3755    1.4182
    
    
    chck(:,:,3) =
    
        1.0871    1.0858    0.9858
        0.9928    0.9767    1.1871
    
    
    chck(:,:,4) =
    
        1.1761    1.0804    1.0861
        1.1772    0.8702    1.2065
    
    

    Input Arguments

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    Input array in decibels, specified as a scalar, vector, matrix, or an array. When ydb is nonscalar, db2mag is an element-wise operation.

    Data Types: single | double

    Output Arguments

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    Magnitude measurements, returned as a scalar, vector, matrix, or an array of the same size as ydb.

    See Also

    Introduced in R2008a