FSDB Files

Many digital or analog simlators generate FSDB files. FSDB stands for “Fast Signal Data Base”. NOVAS developed this file format to replace VCD (value change dump) files. After a number of acquisitions Synopsys Inc owns FSDB.

FSDB files are binary and they make use of data compression. As a consequence they are a lot smaller that VCD files and reading them is a lot faster. Many tools can read and write files in FSDB format.

Like the VCD format, FSDB files are perfect for digital waveforms and a bit less appropriate for analog data. However, as they are so compact, many analog simulators have the option to write waveforms to FSDB files.

Theoretically the x-axis data can hold real values. However in practice the x-axis values are positive integers. As a consequence the x-axis values are discrete. Very small time steps of analog simulators might not always be represented correctly.

All variables are compressed into a single data block. Each block of compressed data represents a time interval. Therefore the whole file must be decompressed for accessing a single curve. Other compression schemes might be a lot faster …

The integer x-axis values must be positive and complex values aren’t supported at all. Therefore analog simulators mostly use FSDB files for transient data.

Our BeSpice tools don’t support FSDB files directly. However we can provide source code that allows you to compile a plug-in for BeSpice Wave.

To compile this plug-in you need the following from Synopsys software distribution:

  • the license to use the following.
  • the header files ffrAPI.h, ffrKit.h and fsdbShr.h.
  • the header file ffwAPI.h if the write functionality is required.
  • the shared libraries libnffr.so and libnsys.so on Linux.
  • the shared library libnffw.so if the write functionality is required on Linux.
  • the shared library nffr.dll on Windows.
  • the shared library nffw.dll if the write functionality is required on Windows.

Please contact our support for more information.

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