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Modular instrumentation has long been attractive for RF/microwave applications, owing to its potential for packing multiple measurement functions into the space where a single-function instrument once stood. But receiving such benefits usually meant a tradeoff in performance, compared to full-sized instruments. However, that is not the case with the fast-switching model M9393A PXIe performance vector signal analyzer (VSA) from Agilent Technologies.

Based on the PXI-Express (PXIe) modular format, this VSA can meet or beat the performance of any available VSA, with 150-μs switching speed and a frequency range of 9 kHz to 27 GHz. Ideal for aerospace and defense applications, it also provides the measurement power for the latest emerging commercial communications standards and advanced modulation formats. It is as much at home on the R&D bench as on the manufacturing/production line.

Modular measurement formats such as VXI and PXI provide not only flexibility and “measurement density” in small footprints, but can also help save on operating costs: They do so by conserving power and packing more functions per measurement space and power supply. For example, a PXI mainframe has 18 card slots within a 19-in.-wide, four-unit-high (4U) chassis.

In addition, these modular instruments can cut measurement times, since digital formats such as PXIe allow for rapid data transfer between the instrument modules and the host personal computer (PC) in a test setup. A modular format such as PXIe can also result in financial savings over time, since modules (and their functions) can be readily exchanged as instrument modifications and improvements are needed.

PXIe Modules Pack Speedy 27-GHz VSA, Fig. 1

The M9393A occupies five slots in a PXIe chassis (Fig. 1), including modules for a microwave frequency downconverter, frequency reference, digitizer/intermediate-frequency (IF) processor, and microwave frequency synthesizer. The frequency reference module can be shared by multiple VSAs, enabling four to fit into a single chassis An ideal PXIe modular companion for the VSA is the firm’s model M9037A PXIe embedded controller, which helps the M9393A achieve its top measurement speed (Fig. 2).

PXIe Modules Pack Speedy 27-GHz VSA, Fig. 2The M9393A VSA actually includes many different frequency options, with available RF/microwave frequency ranges all starting at 9 kHz and terminating at 8.4, 14.0, 18.0, or 27.0 GHz. Optional preamplifiers are available for all four frequency ranges. The analyzers are supplied with a standard analysis bandwidth of 40 MHz, and available with optional analysis bandwidths of 100 and 160 MHz. The standard instrument memory is 128 MSamples, with options for 512 and 1024 MSamples memory.

In terms of performance, no matter the frequency range or analysis bandwidth, the M9393A delivers. Building upon the high levels set earlier in the firm’s lower-frequency model M9391A PXI VSA (in 3- and 6-GHz models), the M9393A provides a wide dynamic range, with a -160-dBm displayed average noise level (DANL) at one end and a +30 dBm third-order-intermodulation (TOI) level at the other. These M9393A VSAs also show signal levels with outstanding ±0.15 dB absolute amplitude accuracy. The extremely compact PXIe configuration of the M9393A VSA, for example, allows four time-synchronized channels to be mounted within a single instrument chassis.

PXIe Modules Pack Speedy 27-GHz VSA, Fig. 3By adding the M9037A PXIe embedded controller (Fig. 3), the measurement capability of the M9393A is increased. The M9037A features a 2.4-GHz quad-core processor with as much as 12 GB/s data bandwidth. Based on the latest i7 series microprocessor from Intel Corp., an i7 4700EQ extended-life processor, the M9037A is essentially a high-performance PC designed for challenging applications.

The M9037A’s 2.4-GHz quad-core processor features as much as 12 Gb/s data bandwidth from the central processing unit (CPU) to the PXIe backplane using PCIe technology, and can support as many as 24 PCIe lanes for multiple-function processing and fast computations on complex measurements, such as microwave power and error-vector-magnitude (EVM) measurements. The M9037A PXIe embedded controller even includes an X8 PCIe front-panel connector to link to a second PXIe chassis or to redundant-array-of- independent-disks (RAID) data storage. It is bolstered by preloaded libraries and drivers, and features the convenience of a front-panel removable 240-Gb solid-state memory drive.

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