A spread spectrum network analyser

The paper describes the realisation of a Spread Spectrum Network Analyser using appropriate software to control a PC interface card, like a soundcard. The software generates a digitised time waveform consisting of a Spread Spectrum signal containing a number of equal amplitude spectral components. The interface card converts this waveform to an analogue signal, which is then passed through the network to be measured and then digitised using the same interface card. The difference between the sent and received spectra is the transfer function of the network and is analysed in both amplitude and phase. This Spread Spectrum Network Analyser is significantly faster than conventional Network Analysers, but suffers from dynamic range limitations. Techniques for increasing the dynamic range are discussed in this paper.