Editorial

Uncertain Times for DefenseADCs and DACs Penetrate Sacred Ground
By Barry Manz

The impact of converting analog signals to digital form is one of the greatest advances the electronics industry has ever achieved.
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Defense News

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Article Highlights China Cruise Missile Threat
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Iran Claims It Reverse-Engineered RQ-170 UAV
Iran says it has copied announced on Sunday that it has copied an RQ-170 Sentinel UAV that it says the country "commandeered" in 2011, after his allegedly being "brought down by the Iranian Armed Forces' electronic warfare unit" in December 2011, according to Iran's Tasnim News Agency. That Iran captured the UAV is not in doubt: U.S. President Barack Obama asked Iran sent to return it after it was captured.

Israeli Navy Gaining Greater Capabilities
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House House to Keep A-10, Other Programs
The House Armed Services Committee (HASC) is opted to fund a broad array of projects and has stated its goal of protecting every possible defense system. For example, the committee left the Lockheed Martin F-35 Joint Strike Fighter largely intact and up the funding for Boeing's EA-18G Growler electronic attack aircraft.

EW Development Key Element of 2015 Budget
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Insight into Hypersonic Weapons
An article in The Interpreter published by the Lowy Institute for International Policy contains an interview by Harry Kazianis, a non-resident senior fellow at the China Policy Institute (University of Nottingham) with John Stillion, a senior fellow at the Center for Strategic and Budgetary Assessments (CSBA) into the workings of hypersonic weapons.

March 2014

ADCs and DACs Penetrate Sacred Ground
By Barry Manz Editor

The impact of converting analog signals to digital form is one of the greatest advances the electronics industry has ever achieved. Although today almost every consumer, industrial, commercial, and military system depends on this capability, one of the last remaining outliers is directly converting analog signals at microwave frequencies into digital data streams without using large amounts of intervening microwave hardware (i.e., downconverters).

At lower frequencies, this has been possible for some time with high-resolution and dynamic range, but above a few gigahertz it has remained elusive unless lower performance could be tolerated. However, systems and even board-level products have recently become available that can perform “direct-to-digital” conversion at frequencies up to at least 6 GHz. Precisely how high in frequency this can actually be accomplished is known only to those with a “need to know” within converter and instrument manufacturers and DoD –but it’s probably a lot higher.

This is (or should be) of interest to manufacturers of microwave downconverters since the higher in frequency direct conversion can be performed the fewer downconversion stages are required. If you could directly capture and digitize signals at 20 GHz at the antenna, whole blocks of front end could be eliminated. The devil, as always, is in the details. When you capture and digitize 20 GHz of spectrum over even a very short period, you end up with an astonishing amount of data.

The resources required to rapidly gain something useful from it are formidable indeed, but if only signals of interest are captured, the capture file can be reduced by orders to make it more manageable. Ironically, separating this spectral wheat from the chaff can also be achieved with fast, broadband microwave tuners coupled with high-speed processors or FPGAs, bringing microwave hardware back in the picture. So while digital converters continue to edge upward in bandwidth, microwave hardware will be difficult to dislodge and projections of the death of the microwave downconverter are arguably premature.

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MMD March 2014

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