Modular instruments at the heart of ‘Reference Solution’

Santa Rosa, CA. Applications that can benefit from modular-instrument architectures range from wireless to high-speed digital and include aerospace/defense, radar, and electronic warfare, according to Sheri DeTomasi, program manager, Software and Modular Solutions Division, Keysight Technologies. In an interview at the company’s headquarters, she said modular solutions offer the necessary performance, scalability, density, and multichannel capabilities to support tasks ranging from 5G research and baseband I/Q chipset design to RF PA/FEM production test and antenna calibration. The solutions, she said, are easy to support and upgrade.

As examples of Keysight’s modular instruments, she cited a 10-Hz to 26.5-GHz PXIe signal analyzer, a single-slot two-port PXI vector network analyzer, and a PXIe vector signal analyzer. In AXIe format, the company offers high-speed arbitrary waveform generators. And the complement the instruments, Keysight offers the 89600 VSA software, Signal Studio signal-creation software, and standard-specific measurement applications. Keysight’s modular strategy, DeTomasi said, removes “one size fits all” constraints while providing a consistent software environment across a product’s lifecycle.

One challenge with respect to modular instruments relates to putting the modules and software together into a complete system. Among the possibilities, the vendor could do this, the customer could, or a third-party integrator could. One approach that Keysight offers comes in the form of a “Reference Solution,” which DeTomasi described as “a market-validated, proven test system for a specific application.” A Reference Solution can include modular instruments and software as well as benchtop instruments.

A customer attempting its own integration faces considerable effort and risk. A Reference Solution, DeTomasi said, absorbs about 80% of that effort and risk, allowing 20% to adapt the solution to the customer’s unique measurement requirements.

Keysight’s latest Reference Solution applies to 5G channel sounding (read more here). Channel sounding, DeTomasi explained, helps researchers characterize the RF channel they propose to use with respect to parameters such as path loss, delay, absorption, reflection, multipath effects, Doppler shift, and multipath fading through measurement of channel impulse response (CIR). For the mmWave channels being considered for 5G, she said, radio-wave propagation is not well understood, creating a need for effective channel-sounding strategies.

For channel sounding, she said, one can employ a sliding-correlator or frequency-swept approach, with the former offering amplitude information only and with both offering low measurement speeds. Keysight recommends a wideband correlation approach, which is fast and provides both amplitude and phase information. And for MIMO sounding, Keysight suggests a “switching at transmit, parallel receive” approach, which is fast and eliminates cross-interference, in contrast a switching at both transmit and receive approach, which is slow, and a parallel transmit and receive approach, which is fast but adds cross interference.

A channel sounding system, DeTomasi said, requires ultrawideband, mmWave signal generation and capture, multichannel capability, data storage, channel-parameter estimation processing, and calibration and synchronization. The system pictured includes an M9703A AXIe 12-bit, 3.2-GS/s wideband digitizer, an M9362A-D01 PXIe microwave downconverter, an M9352A PXI hybrid amplifier/attenuator, an N5183B MXG microwave analog signal generator, an E8267D PSG vector signal generator, an M8190A 12-GS/s arbitrary waveform generator, 89600 VSA software, and Waveform Creator software.

The new 5G Channel Sounding Reference Solution complements other Keysight Reference Solutions, beginning with the first one, which addresses RF PA/FEM characterization and test, introduced in April of 2014 and last updated in May. Other Reference Solutions address multichannel antenna calibration, multichannel LTE-A test, and satellite signal monitoring.