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dB Gain

Apply decibel gain


Math Functions / Math Operations


  • dB Gain block


The dB Gain block multiplies the input by the decibel values specified in the Gain parameter. For an M-by-N input matrix u with elements uij, the Gain parameter can be a real M-by-N matrix with elements gij to be multiplied element-wise with the input, or a real scalar.


The value of k is 10 for power signals (select Power as the Input signal parameter) and 20 for voltage signals (select Amplitude as the Input signal parameter).

The value of the equivalent linear gain


is displayed in the block icon below the dB gain value. The output is the same size as the input.

The dB Gain block supports real and complex floating-point and fixed-point data types.

Fixed-Point Data Types

The following diagram shows the data types used within the dB Gain subsystem block for fixed-point signals.

The settings for the fixed-point parameters of the Gain block in the diagram above are as follows:

  • Integer rounding mode: Floor

  • Saturate on integer overflow — unselected

  • Parameter data type mode — Inherit via internal rule

  • Output data type mode — Inherit via internal rule

See the Gain (Simulink) reference page for more information.



The dB gain to apply to the input, a scalar or a real M-by-N matrix. Tunable (Simulink).

Input signal

The type of input signal: Power or Amplitude. Tunable (Simulink).


This block does not support tunability in generated code.

Supported Data Types

  • Double-precision floating point

  • Single-precision floating point

  • Fixed point (signed and unsigned)

  • 8-, 16-, and 32-bit signed integers

  • 8-, 16-, and 32-bit unsigned integers

See Also

dB ConversionDSP System Toolbox
Math Function (Simulink)Simulink

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using Simulink® Coder™.

Fixed-Point Conversion
Design and simulate fixed-point systems using Fixed-Point Designer™.

Version History

Introduced before R2006a