Record High Frequency Achieved

eldavojohn writes "Researchers at UCLA Henry Samueli School of Engineering and Applied Science managed to push our control of frequencies to another level when they hit a submillimeter 324 gigahertz frequency. As any signal geek out there might tell you, this is a non-trivial task. 'With traditional 90-nanometer CMOS circuit approaches, it is virtually impossible to generate usable submillimeter signals with a frequency higher than about 190 GHz. That's because conventional oscillator circuits are nonlinear systems in which increases in frequency are accompanied by a corresponding loss in gain or efficiency and an increase in noise, making them unsuitable for practical applications.' The article also talks about the surprising applications this new technology may evolve into."

First Guess: +1, Patriotistic

[Anonymous Coward]

New weapons for the military-industrial-Congressional complex [sourcewatch.org].

War mongeringly yours,
George W. Bush [whitehouse.org]

How they did it

[$RANDOMLUSER]

The researchers first generated a voltage-controlled CMOS oscillator, or CMOS VCO, operating at a fundamental frequency of 81GHz with phase-shifted outputs at 0, 90, 180 and 270 degrees, respectively. By linearly superimposing these four (or quadruple) rectified phase-shifted outputs in real time, they ultimately generated a waveform with a resultant oscillation frequency that is four times the fundamental frequency, or 324 GHz.

Sounds like there's room to scale, using this method.

Re:How they did it

[Anonymous Coward]

You can't generate new frequencies by linearly superposition. This means that all they did was cancel low harmonics of a not-so-sine wave to "see better" some high harmonic. But this high harmonic was already present in each individual oscillator, so one could say that the frequency was already "achieved".

If aliens are calling...

[JAB Creations]

If aliens are calling then they'd probably be using frequencies along those lines. The logic would be that if they found using such frequencies to be technologically challenging to use why would they bother to communicate with an abundance of lesser civilizations when they could potentially benefit from communicating with equal or superior civilizations across the cosmos?

Short amount of time???

[msauve]

Red/orange LEDs typically have a lifetime measured in the 10,000+ hour range, when reasonably driven. A $1 blue LED will provide a reliable 600+ THz.

"submillimeter"

[ebcdic]

Sincer "submillimeter" implies a frequency greater than 300GHz, it makes no sense to talk about "usable submillimeter signals with a frequency higher than about 190 GHz".

Nice try

[Headcase88]

This post was clearly planted by the U.S. government.

Re:How they did it

[TerranFury]

Perhaps the technique is standard frequency mixing [wikipedia.org], a standard technique used in practically every radio receiver these days.

Aye, the heterodyne radio receiver. Yeah, I could see them using a mixer! That doesn't mesh with what's described, but, then, (unless I am missing something), what's described doesn't make a ton of sense:
From TFA:

The researchers first generated a voltage-controlled CMOS oscillator, or CMOS VCO, operating at a fundamental frequency of 81GHz with phase-shifted outputs at 0, 90, 180 and 270 degrees, respectively. By linearly superimposing these four (or quadruple) rectified phase-shifted outputs in real time, they ultimately generated a waveform with a resultant oscillation frequency that is four times the fundamental frequency, or 324 GHz.

How can any linear system create an output frequency unequal to one of the input frequencies? I could see rectification as providing a frequency doubling -- but that's old, old news, generates horrid output, and is probably not what's referenced here.

So maybe the article gets it wrong, and you're right?

If somebody else could shed some light on this, that'd be cool.

Re:How they did it

[Beryllium Sphere(tm)]

A full-wave rectifier works like a frequency doubler, and the article makes it sound like they've extended that to get a frequency quadrupler.

One significant point here is that the FCC only claims jurisdiction up to 300 GHz.