In August we announced the Open Instrumentation Project (OIP), which supports open-source software and low cost hardware for electronic instrumentation.
One of the instruments is a VNA (vector network analyser) that measures amplitude and phase response over the frequency range 0.1Hz to 100kHz. The VNA is available as Open Software, working with the Syscomp DSO-101 oscilloscope and WGM-101 waveform generator.
The mechanics of the VNA are described in an article in the September issue of Circuit Cellar, titled 'Programmable Network Analyser'.
Further detail is available in the paper 'A Software-Based Network Analyser' at the Papers section of the Syscomp web page:
Another paper 'Audio Measurements with a Network Analyser' describes audio applications of the VNA and is available from the same web page.
Screen shots and the software for these instruments are available from sourceforge at:
The software is licensed under the GPL.
The oscilloscope and waveform generator are described on the Syscomp web page at