07 September 2007

Turning steps into escalators, nano style

With the week past, it's time to kick back a little, put work aside, and maybe reflect a bit. Idly checking my web hit statistics for the week, I note a few hits from people googling my name combined with "HyperBit™" --my technology to increase the resolution of digital-to-analog converters (DACs).

First, hello to you googlers. I hope the following answers your questions. Please email me at scott.c.jordan "at" gmail.com if not.

We live in an analog world. For our digital toys to connect to the world, their bits and bytes need to be converted to old-fashioned voltages and currents. DACs are the specialized chips which do that. Now, like any digital circuit, DACs have limits in terms of the size of the biggest numbers they can digest-- this defines the number of voltage steps they can produce. Most DACs are limited to 4,096 or 65,536 steps.

Sometimes you need more. For a nanopositioner of 300 micron travel, dividing its range into 65,536 steps equates to about 5 nanometers per step. Many applications can benefit from even more (finer) steps. Until now those would require really high-performance digital nanopositioning controllers. But if you are designing your own circuit to output a voltage or using a National Instruments multifunction board (or perhaps doing something completely outside the realm of nanopositioning), you might be out of luck. Higher-resolution DACs are available but most are optimized for audio and consumer applications rather than instrumentation applications, which can lead to drawbacks. And switching out DAC chips might not be an option; you might be limited to whatever's soldered into your setup.

Here comes HyperBit™ (U.S. patent 6,950,050). Implemented either in software or hardware, it teases extra application resolution--lots of it!--out of existing DACs. It can, for example, improve the resolution of a nanopositioner by two to three orders of magnitude. While your ultimate performance limit depends on your hardware and environment, it's pretty safe to say that the DAC won't be a bottleneck anymore.

Unlike the other YouTube videos linked in this blog, the video above is my own. It uses a home-made millivoltmeter to demonstrate the technology's benefits. It runs less than two minutes; take a look. We've already published on it for piezo and MEMS nanopositioners. Besides hardware implementations, it has been implemented in LabVIEW, LabVIEW FPGA and in a DLL.

Many other mechanisms and circuits can benefit. If it looks like something your applications or designs can use, drop me a line ...before your competitor does.

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