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Libre Filter Design and Analysis Tool

Libre fdatool quick start

Last edited by Erik van der Bij
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Libre-FDATool Quick Start

TODO: this page is under development

Introduction

Once you have a installed Libre-FDATool compatible Python environment or a deployed Libre-FDASys virtual appliance, you must execute the librefdatool.py* script to launch the GUI. Then, follow this tutorial for a quick-start.

in addition, you can find some how-to's on the Libre-FDATool Youtube channel

Controls description

Libre-FDATool working mechanism is very simple. It works as a basic filter simulator, in which you define a stimulus, then configure a filter and finally execute a simulation.

In the GUI, there is a tab for each of the basic steps -- stimulus, filter and simulator.

HDL code generation is automatically executed when a simulation is performed.

Here we have a quick description of the different GUI tabs that control Libre-FDATool.

Stimulus

In the stimulus tab, we can configure the signal that is going to be sourced to the filter. Here, w can modify the waveform type, frequency, amplitude, length...

Filter

In the filter tab, we define the filter that is going to be used.

There are two basic configuration blocks:

  • Hardware Realization: here, the different HDL model parameters are defined, such as the filter structure or the Fixed Point configuration for coefficients and input/output ports
  • Filter Parameters: in this configuration box, we can select different high-level filter specs recipes in order to calculate the LTI system coefficients. There are different configurable parameters for every FIR or IIR filter recipe, such as window method, order, cut-off frequencies...

Once we have configured the filter, we can analyze the expected transfer function for both exact floating point and digital HDL model.

Simulator

In the simulator tab, we have the controls for choosing which simulator engine Icarus Verilog / GHDL and HDL language Verilog / VHDL we want to use.

In addition we can choose the name for the filter UUT and the workspace folder. When a simulation is performed, the correspondent HDL files for device and testbench are automatically generated on the workspace folder using the assigned name.

In order to launch a simulation, we must click on the gear button placed on the toolbar. This button is accessible from any tab, and when the simulation has finished, Libre-FDATool will automatically open the simulator tab.

In the simulator tab scope we can see the respective filtered signals for both floating point model and digital HDL simulation. We can choose to view the response in time, plot the absolute error or estimate the power spectrum.