IN MY OPINION

Evaluating Our Industry’s Health Requires a Broad Perspective
By John Farley, Director of Marketing, Pasternack Enterprises

As most RF and microwave companies are privately held and industry analysts rarely track sales of microwave components other than semiconductors and interconnects, determining the health of an industry as diverse as ours is extremely difficult.
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MILITARY MICROWAVE DIGEST


MMD March 2014
New Military Microwave Digest

ON THE MARKET


E-Band Active X5 Multiplier
Model SFA-743843516-12SF-N1 is an E-band X5 active multiplier with center frequency at 79 GHz with minimum +/-5 GHz operational bandwidth. It converts 14.8 to 16.8 GHz/+5 dBm input signal to deliver 74 to 84 GHz frequency band with more than +16 dBm power.
Sage Millimeter

Hand-Flex™ Coaxial Cable
Covering DC to 12.5 GHz, this 8” coaxial cable, 141-8SMNB+, has a bulkhead Female Type-N connector at one end and SMA-Male at the other. Features include low loss, excellent return loss, hand formable, and an 8mm bend radius for tight installations.
Mini-Circuits

Phase Trimmer Series
This new phase trimmer series is designed for RF applications where phase match between two cables is needed for proper system performance. Phase trimmers, offered from DC to 50 GHz, will give an accurate phase adjustment over a specified frequency range.
RLC Electronics

Planar Monolithics Industries
Model PTRAN-100M18G-SFB-3UVPX-MAH is a transceiver covering the frequency range of 100 MHz to 18 GHz. The transceiver fits into a 3U Open VPX form factor utilizing the high speed VITA 67 RF connector.
Planar Monolithics Industries

SMT High-Power Attenuators
Now available with full design support capabilities are three new SMT high-power attenuators from Anaren. These 30 to 50W devices are high-performance, high-power chip attenuators covering DC to 3.0 GHz and feature high return loss and small footprints.
Richardson RFPD

See all products in this issue


 

November 2013

The New Face of Hardware in the Loop
By Justin Panzer, Business Development Manager, Tektronix

Liam Devlin, CEO, Plextek RF Integration

The extraordinary complexity of smartphones, tablets, and other wireless-enabled products coupled with new product “sell-by” dates measured in months can make design, testing, and verification a formidable challenge at best. This assumes that prototype hardware is even available to test throughout the process, which there often is not. In short, it is no longer economically feasible to wait for systems to be built before evaluating their constituent functional blocks using real-world stimuli. It’s not surprising then that testing of RF and microwave subsystems and systems with hardware-in-the-loop (HIL) has evolved from rudimentary to revolutionary in less than a decade.

HIL itself is hardly new, and has been used in developing automotive, industrial, aerospace, automation systems (among others) for many years. Even in the RF and microwave domain, HIL has been employed for decades --- using noise sources to stimulate mobile phones and satellite communications terminals for example. However, the difference today is the versatility of the test equipment used to realize HIL and how it can reduce development time, cost, and angst. The real-time spectrum analyzer and arbitrary waveform generator can play important roles in obtaining these benefits.

It was once common practice to produce a working system or major subsystem prototype before subjecting it to the signal environments it would experience in service. Using the wireless industry as an example, in the mid 1990s when CDMA one was first deployed as part of the IS-95 standard, Additive White Gaussian Noise (AWGN) was the stimulus employed to test CMDA system performance. This provided a fair approximation of a signal environment--and there was no better option. However, when placed into service, base station transceivers often performed poorly in the real world to which they had never been exposed.

As digital transmission schemes evolved and began to use higher-order modulation schemes, simulation with such a simplistic stimulus was no longer acceptable. Test equipment manufacturers, whose requirement is always to be a step ahead of what their customers need, quickly harnessed the most advanced digital signal processing available to produce arbitrary waveform generators and dedicated test systems capable of producing representative stimulus signals at baseband and RF frequencies. This allowed the subsystem under test to be exposed to exact replicas of signals contained in the latest standard, legacy standards, or basically any waveform the designer required.

Today not only can these test systems produce these signals, they can produce entire signal environments, including impairments such as multipath and fading, multiple signals of various types, as well as interference, singly or together. Without this ability, the development of wireless-enabled devices would require significant redesign and testing, resulting in development cycles that would well exceed the time available.

The need for accurate stimulus signals is made even more important as the FCC attempts to cram as many services as possible in a given amount of spectrum and reduces guard bands between them. This places an enormous burden on RF power amplifiers as they must be squeaky clean (no spurs, no spectral regrowth) and on receivers that must be highly resistant to interference. Only by subjecting the transmit and receive signal paths to realistic signal environments at one or more stages of development can a reasonable margin of safety be ensured.

The consumer market offers a good example of the power of HIL testing, but it is far from the only one. Defense systems, whether battlefield radios, satcom terminals and transponders, electronic attack and protection systems, or radars, must perform in extraordinarily dense signal environments created by emitters they cannot control. Dropped calls are minor annoyances compared to soldiers in-theater whose radios don’t work or fighter pilots whose radar warning receiver miss a threat.

An EW, SIGINT, or ELINT system captures signals at RF, digitizes them, processes them, reconverts them to RF, and in the case of a jammer, retransmits them in a form designed to “fool” the threat. A real-time spectrum analyzer can be used to capture these signals, which can then be used at baseband or RF to which the system-under-development can be subjected. An arbitrary waveform generator can be inserted in this “loop” to help create the waveforms and waveform sequences that form the stimulus signal.

In many locations throughout the world, even a relatively short-term recording of RF activity at frequencies in the most densely-populated areas of the spectrum and within a relatively narrow bandwidth can be quite long. In fact, surveillance systems often remain in place for days to find random, intermittent, or other signals of interest. Storage for such capture files requires terabytes of storage, which is far beyond what a bench-top instrument can store, as mass storage is obviously not required in its primary roles.

For this purpose, spectrum analyzers can be supported by long-duration RF signal capture, record them as baseband I&Q signals, and played back either at baseband or quadrature modulated to the original or any other frequency. In between, software tools can be used to find “signals of interest” in this spectral haystack along with where and when they were recorded. Instances of their occurrence can be extracted from the main spectrum capture file and passed to RF editing software that allows a new, much smaller file to be created that includes only the signals of interest. This file can be used as a stimulus for the system under development – and a variety of other purposes as well.

These are just a few of the many examples of how real-time spectrum analyzers and arbitrary waveform generators can provide significant benefits in an HIL environment. In each one, their unique capabilities can make the difference between creating a product that works as intended and gets to the marketplace on time.

Tektronix
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FROM WHERE WE SIT

Uncertain Times for DefenseIn Defense of DARPA; Lamenting Bell Labs
By Barry Manz

A federal agency like DARPA is a sitting duck for politicians and assorted other critics. It has come up with some truly bizarre programs over years that ultimately either delivered no tangible results, were canceled before they could cause any damage, or attempted to answer questions that nobody was asking or needed answers to. Read More...


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