Python Block Message Passing

The previous tutorial, Creating Your First Block, demonstrates how to create a Python block using the Embedded Python Block. The next tutorial, Low Pass Filter Example, demonstrates how to use filtering blocks in GNU Radio.

Message Passing Overview

Messages are an asynchronous way to send information between blocks. Messages are good at conveying control data, maintaining a consistent state across blocks and providing some forms of non-data feedback to blocks in a flowgraph. There is no sample-clock based guarantee when they will arrive and messages are not associated with a specific sample like a tag.

• grey color
• message debug sink

PMT

describe basic PMT types

link against other PMT pages

Creating a Message Output Port

• saving code 'compiles' the python and error messages are displayed the EPB window

• message ports do not have to be connected like stream/vector ports

The next tutorial, Low Pass Filter Example, demonstrates how to use filtering blocks in GNU Radio.