Modular instruments offer advantages over traditional benchtop test equipment in addition to simply being smaller. For one thing, given the ease of mixing and matching modular instruments, such as in the PXI format, functionality can be changed by simply swapping modules and supplying the appropriate control software. If armed with suitable instrument modules, almost any test can be executed. By introducing a total of 48 different instrument modules at one time, Agilent Technologies has not only shown its commitment to modular testing, but has provided the capability for a host of different measurements.

For Agilent, a company with a rich history (originally as Hewlett-Packard Co.) in benchtop instruments, the multiple-module launch demonstrates the firm's willingness to listen to its customers, where a solution may require benchtop equipment, modular equipment, or a combination of the two formats. According to Ron Nersesian, President of Agilent's Electronic Measurement Group, "Agilent is committed to providing exceptional test solutions in the platform that customers prefer -- whether a benchtop, handheld, or modular format. Rarely is a single hardware or software solution the right answer for every test scenario. Now whether they're involved in sophisticated research, development, design or manufacturing, system developers will be able to achieve new levels of speed, performance and flexibility with our PXI and AXIe products."

The two modular instrument formats bring with them savings in cost and time to develop systems-level solutions. The PCI eXtensions for Instrumentation (PXI) format, for example, is based on the personal computer (PC) concept of connecting different function blocks to form a system. Developed by National Instruments as an open standard, it combines the Peripheral Component Interconnect (PCI) electrical bus with the rugged mechanical packaging of the CompactPCI format. It also includes mechanical, electrical, and software features suitable for test and measurement applications. The other modular format, AdvancedTCA Extensions for Instrumentation and Test (AXIe), is a high-performance version of PXI, and leverages the PXI, LXI, and IVI standards. Developed by cooperation among Aeroflex, Agilent, and Test Evolution Corporation, this modular format extends the Advanced Telecom Computing Architecture (AdvancedTCA) for general purpose and semiconductor test.

Agilent's 48 new modular products (see figure) include both PXI and AXIe units, with functions such as digitizers, arbitrary waveform generators, digitizing oscilloscopes, switches, frequency converters, and local oscillators (LOs). Operating frequencies range as high as 26.5 GHz for the downconverters, and to 10 GHz for the LOs. For example, model M9302A is a PXI LO that tunes from 3 to 10 GHz with 0.1-Hz resolution. It occupies two slots in a 3U PXI chassis. The single-sideband (SSB) phase noise is -118 dBc/Hz offset 20 kHz from a 10-GHz carrier. The LO source supplies output power of +16 dBm across the frequency range with 2 dB output accuracy.

The model M9302A PXI LO source conforms to the Modular Open Systems Approach (MOSA) for PXI form factor with connector compatibility that allows its use with compact PCI (cPCI), PXI-1, and PXI-e Hybrid slot formats. It is designed for use with Microsoft Windows XP, Vista (32- and 64-b), and Windows 7 (32- and 64-b) operating systems, and includes software drivers, software front panels, and programming examples in LabVIEW, LabWindows/CVI, Visual Studio, C, C++, C#, Visual Basic, and MATLAB for reduced development time of automated measurement programs.

Also in the realm of signal generation, model M9330A is a PXI-H arbitrary waveform generator that operates at update rates to 1.25 GSamples/s with 15-b vertical resolution. Ideal for testing aerospace, radar, and wireless communications systems, the arbitrary waveform generator provides dual output channels for generating in-phase (I) and quadrature (Q) signal components used to create complex digital modulation formats. The module occupies four slots in a 3U PXI mainframe. It achieves a bandwidth of 500 MHz per channel, or a full modulated bandwidth of 1 GHz in an I/Q format. As with the LO source, it is supported by a wide range of operating systems and applications software. In addition, for simulating multiple-emitter environments, multiple M9330A modules can be synchronized to create a compact signal source. As with the LO source, the M9330A is compatible with PXI, PXI-H, and cPCI connector configurations.

When the requirements for vertical bit resolution are less demanding, the company also offers the model M9331A PXI-H arbitrary waveform generator with 10-b vertical resolution. The model M9331A operates at update rates to 1.25 GSamples/s. It also provides dual outputs, with bandwidths of 500 MHz per channel, or 1 GHz when the channels are combined to form a complex modulated output signal. It is also compatible with PXI, PXI-H, and cPCI connector configurations.

On the signal processing side, the model M9360A attenuator/preselector packs a four-stage YIG-tuned filter preselector and analog switched attenuator into a two-slot, 3U PXI module. The tunable filter offers better than 5 ms tuning speed for a 50-MHz step and has a minimum 3-dB filter bandwidth of 40 MHz, with maximum of 3-dB filter bandwidth of 120 MHz. Ideal for applications in testing defense, radar, and wireless communications systems, the attenuator/ preselector filter covers a range of 100 kHz to 26.5 GHz. It provides a bypass signal path for automatically routing signals around the band-limited preselector for additional bandwidth when needed. The attenuation is available from 0 to 70 dB in 10-dB steps. The module employs reliable single-pole, double-throw (SPDT) mechanical switches for selecting signal paths and signal conditioning. As with the other modules, it conforms to MOSA standards and is compatible with cPCI, PXI-1, and PXIe Hybrid slot connector configurations.

Also on the signal-processing side, the model M9361A frequency downconverter translates an input frequency range of 2.75 to 26.5 GHz to baseband signals with 250-MHz bandwidth centered at an intermediate frequency (IF) of 500 MHz. A built-in preamplifier makes it possible to process input signals as low in level as -160 dBm, while built-in calibration simplifies system power budget calculations. Housed in a single-slot 3U PXI module, the frequency downconverter can handle an input signal level range of -160 to -30 dBm. For frequency-translation chores requiring less frequency range, the company also offers the model M9351A frequency downconverter with input range of 50 MHz to 2.9 GHz and 40-MHz IF bandwidth centered at 500 MHz.

A trio of microwave switches cover DC to 26.5 GHz in PXI-H modules. Model M9155C is a dual single-pole, double-throw (SPDT) switch that fits in a one-slot module, with insertion loss of 0.96 dB or less and 50 dB or better isolation through 26.5 GHz. Model M9156C is a dual transfer switch in a two-slot module with better than 57 dB isolation and less than 0.86 dB insertion loss for most of the 26.5-GHz bandwidth. Model M9157C is a single-pole, six-throw (SP6T) switch in three slots with better than 60 dB isolation and less than 0.70 dB loss to 26.5 GHz.

In terms of signal analysis, the Agilent collection includes a high-performance PXI vector signal analyzer (VSA), several IF digitizers, and several digital oscilloscopes. The VSA, model M9392A, offers a 250-MHz instantaneous bandwidth across a frequency range of 50 MHz to 26.5 GHz. When combined with the firm's 89601A VSA software, the M9392A forms a complete microwave VSA solution for analysis of communications, radar, and avionics signals in a modular, open-system standard. The M9392A actually consists of a number of separate modules: the M9202A PXIe IF digitizer, the M9302A PXI LO, the P9360A PXI attenuator/preselector, and the M9361A and M9351A PXI downconverter modules. Together, they form a VSA capable of a displayed average noise level (DANL) of -160 dBm/Hz.

Model M9210A is a single-slot PXI-H two-channel digitizing oscilloscope with maximum sample rate of 2 to 4 GSamples/s (depending on two-channel or single-channel use) and 10-b vertical resolution. It captures an input bandwidth of 1.4 GHz and stores samples on 512 MSamples of memory. The IF digitizers include singleslot PXI-H modules: single-channel model M9202A with 12-b resolution, 2 Gsamples/s maximum update rate, and 1 GHz bandwidth, and single-channel model M9211A, with 10-b resolution, 4 Gsamples/s maximum update rate, and 3 GHz bandwidth.

For housing these modules, the company offers several chassis options, including the model M9018A PXIe chassis, and a pair of AXIe 1.0 chassis, in 2U two-slot (model M9502A) and 4U five-slot form (model M9505A). P&A: from less than $2000 to $42,000 for modules; from $7500 for chassis. Agilent Technologies, 5301 Stevens Creek Blvd., Santa Clara, CA 95051; (877) 424-4536, (408) 345-8886, FAX: (408) 345-8474, Internet: www.agilent.com.