# dB Gain

Apply decibel gain

Libraries:
DSP System Toolbox / Math Functions / Math Operations

## Description

The dB Gain block multiplies the input by the decibel values specified in the Gain parameter. You can specify the input to be a power signal or a voltage signal.

For more information on how the block applies the decibel gain, see Algorithms.

## Ports

### Input

expand all

Specify the input signal as a scalar, vector, or a matrix of size M-by-N.

Data Types: `single` | `double` | `int8` | `int16` | `int32` | `uint8` | `uint16` | `uint32` | `fixed point`
Complex Number Support: Yes

### Output

expand all

Output after applying the decibel gain, returned as a scalar, vector, or a matrix of the same size, data type, and complexity as the input signal.

For more information on how the block applies the decibel gain, see Algorithms.

Data Types: `single` | `double` | `int8` | `int16` | `int32` | `uint8` | `uint16` | `uint32` | `fixed point`
Complex Number Support: Yes

## Parameters

expand all

Note

This block does not support tunability in generated code.

Specify the dB gain to apply to the input as a scalar or a real matrix of the same size as the input matrix.

Tunable: Yes

Specify the type of input signal as one of these:

• `Power` –– The block treats the signal as the power signal.

• `Amplitude` –– The block treats the signal as the voltage signal.

Tunable: Yes

## Block Characteristics

 Data Types `double` | `fixed point` | `integer` | `single` Direct Feedthrough `no` Multidimensional Signals `no` Variable-Size Signals `no` Zero-Crossing Detection `no`

expand all

## Algorithms

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.

`${y}_{ij}={u}_{ij}{10}^{\left({g}_{ij}/k\right)}$`

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

`${g}_{ij}^{lin}={10}^{\left({g}_{ij}/k\right)}$`

is displayed in the block icon below the dB gain value.

## Version History

Introduced before R2006a