At European Microwave Week 2025, Electronic Specifier’s Editor, Mick Elliott speaks to Florian Ramian, Company Applications Engineer, at Rohde & Schwarz about the FSWX signal and spectrum analyser and he explains how the instruments enables completely new measurement scenarios in RF system testing.
Demonstrating the analyser, Ramian spoke how the FSWX’s dual-channel architecture opens possibilities that were previously unavailable in signal analysis. The instrument features two fully phase-coherent input paths, allowing engineers to directly compare a device under test’s input and output in real time. In standard single-channel operation, measurements often include distortions and noise from both the device and the measurement setup itself, potentially obscuring precise characterisation. By contrast, dual-channel operation isolates the device’s behaviour, improving metrics such as error vector magnitude (EVM) and revealing nonlinearities more clearly.
Ramian then showcased the system’s ability to measure absolute phase and group delay, which is unique to a phase-coherent dual-channel analyser. This capability enables engineers to track phase differences and delays through a device under realistic signal conditions, such as a fully modulated 32 APSK signal. These measurements are essential for assessing complex RF components like power amplifiers, providing insights that single-channel analysers cannot.
In addition to signal analysis, the FSWX incorporates advanced spectrum analysis tools. Notably is the use of cross-correlation, borrowed from phase noise testing, to enhance dynamic range. This technique reduces the impact of instrument noise, particularly at the spectral edges, by around 10dB without significantly increasing sweep time. Ramian demonstrated how the RMS cross-correlation detector differentiates genuine signal characteristics from noise contributed by the analyser itself.
Although the FSWX has been available for only a short time, it has had a varied reaction from users. Some immediately recognised its potential, while others were intrigued but uncertain how to apply it to their work. The company anticipates that as engineers explore dual-channel, phase-coherent measurements across different signal types including 5G and other advanced modulations – new applications will continue to emerge. The instrument’s flexibility and depth suggest it will play a central role in refining RF system testing and characterisation.
Watch the video below to learn more.
