Creating Your First Block
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This tutorial will guide you through creating your first block with the Embedded Python Block.
Embedded Python Block
The Embedded Python Block is a tool to quickly prototype a block within a flowgraph. Search for the Python Block and add it to the workspace:
Double-click the box to edit the properties. The Embedded Python Block has two properties,
- Code, a click-box which contains a link to the Python code for the block and
- Example_Param, an input parameter to the block.
Click on Open in Editor to edit the Python code:
You will be prompted with another choice for which editor to use to write the Python code. Click Use Default:
An editor window will then display the Python code for the Embedded Python Block:
Editing Python Block Code
There are three important sections in the Python block code:
- import statements in green
- __init__ function in orange
- work function in red
The import statement includes the NumPy and GNU Radio libraries.
The __init__ statement:
- Accepts the example_param parameter with a default argument of 1.0
- Declares the block to have a np.complex64 input and output, which is the GNU Radio Complex Float 32 data type
- Stores the self.example_param variable from the input parameter
The work function:
- Has the input input_items and output output_items parameters
- Applies a mathematical operation to input_items and stores the result in output_items
- Returns the number of samples produced