gr-uhd GRC Examples

This repository contains a collection of GNU Radio Companion (GRC) examples that demonstrate how to use the gr-uhd module. The gr-uhd module is a GNU Radio module that provides a set of blocks for interfacing with UHD-compatible software-defined radios (SDRs).

General UHD Examples

All examples that start with uhd_*.grc are examples that show off the basic (multi_usrp-based) UHD blocks (i.e., the USRP Sink and Source blocks).

The uhd_fft.grc and uhd_siggen_gui.grc examples are simplified versions of the command-line utilities with the same name.

RFNoC Examples

All examples that start with rfnoc_*.grc are examples that show off the RFNoC API. RFNoC (RF Network-on-Chip) is a framework accessing the FPGA within most USRPs, and allows more fine-grained control over the USRP's signal processing capabilities.

Most examples require that you are running an FPGA bitfile with the relevant RFNoC blocks instantiated. For example, the rfnoc_siggen.grc will not work if the SigGen RFNoC block is not present in the device that you are targeting. On top of that, the blocks must be wired up in a way that is compatible with the flowgraph you are trying to run.

Many of the rfnoc_*.grc show the functionality of one specific RFNoC block in an isolated manner. For example, rfnoc_fir_filter.grc will generate noise in GNU Radio, send it to the FIR Filter RFNoC block, and then receive the filtered signal and display it in a frequency sink.

The rfnoc_duc_radio.grc and rfnoc_radio_ddc.grc examples will work with standard bitfiles, and use the Radio and DDC/DUC blocks.

A more sophisticated example is rfnoc_radio_loopback.grc, which also works with a standard bitfile on most USRPs. This example demonstrates how to use the RFNoC API to create a loopback from the TX to the RX chain, which requires declaring connections as back-edges.

RFNoC Image Builder Files

The rfnoc_images subdirectory contains image builder files. These files are not meant to be executed within GRC, but are input files for the RFNoC Image builder. This is an alternative workflow to editing image core YAML files by hand.