scale_var :
A variable scaler for an xreal-typed signal.
The scale_var primitive produces its xreal-typed output out by scaling an xreal-typed input in with a variable real-typed scale factor scale.
Input/Output Terminals
| Name | I/O | Type | Description |
| out | output | xreal | output signal |
| in | input | xreal | input signal |
| scale | input | real | scale factor |