# Multiply Const

From GNU Radio

Multiplies the input stream by a scalar or vector constant (element-wise if vector).

output = input * constant

See Fast_Multiply_Const for a more performant version of this block for **scalar** values only.

`Added in 3.8`

If the input is a **not** a vector, the "Fast" version is automatically invoked (done behind the scenes).

## Parameters[edit]

(*R*): *Run-time adjustable*

- Constant (
*R*) - Scalar or vector constant. If the input is a vector, this parameter must be a vector of the same size. To multiply all the input items by the same value, use Fast_Multiply_Const.

## Example Flowgraph[edit]

This flowgraph uses three Multiply type blocks. The top Multiply Const Block and middle Multiply Block are driven by the GUI Chooser to act as a Transmit / Receive switch. The bottom Multiply Const Block is a Volume control, the 'constant' being the 'volume' parameter from the QT GUI Range block.

Note: The lower section is a working 2 meter NBFM receiver.

## Source Files[edit]

- C++ files
- If single sample input
- If vector input

- Header files
- If single sample input
- If vector input

- Public header files
- If single sample input
- If vector input

- Block definition
- [1]