New method reveals all you need to know about 'waveforms'

October 7, 2009

The National Institute of Standards and Technology has unveiled a method for calibrating entire waveforms -- graphical shapes showing how electrical signals vary over time -- rather than just parts of waveforms as is current practice. The new method improves accuracy in calibrations of oscilloscopes, common test instruments that measure voltage in communications and electronics devices, and potentially could boost performance and save money in other fields ranging from medical testing to structural analysis to remote sensing.

A waveform can take many different shapes, from staircase steps to irregular curves. A waveform typically is described by a single number—some key parameter of interest in a particular application. For example, engineers have described waveforms using terms such as pulse duration, or transition time between the levels representing '0' and '1' (the binary code used in digital electronics). But waveforms can be diverse and complex, especially in advanced high-speed devices, and a traditional analysis may not distinguish between similar shapes that differ in subtle ways. The result can be signal mistakes (a 1 mistaken for a 0, for instance) or misidentification of defects.

NIST's new calibration method* defines waveforms completely, providing both signal reading and measurement uncertainty at regular intervals along the entire wave, and for the first time makes waveform calibrations traceable to fundamental physics. The mathematics-intensive method is laborious and currently is performed only at NIST (which has more than 750 oscilloscopes), but the developers plan to write a software program that will automate the technique and make it transferable to other users.

The new method offers NIST calibration customers, including major manufacturers and the military, more comprehensive characterization of a greater variety of waveforms, and helps to meet current and future demands for measurements at ever-higher frequencies, data rates, and bandwidths. The impact could be far reaching. The global market for oscilloscopes is $1.2 billion. Anecdotal data suggest that for one product alone, Ethernet optical fiber transceivers, industry could save tens or even hundreds of millions of dollars through manufacturing innovations (such as the new NIST method) that reduce component reject rates and/or boost yields.

Of particular interest to scientists and engineers, the NIST calibration method incorporates new techniques for quantifying errors in waveform measurements. This allows, for the first time, accurate transfer of measurement uncertainties between the time domain (results arranged by time) and the frequency domain (the same data arranged by frequency). Researchers in many fields have long used a technique called "Fourier transform," which reveals patterns in a sequence of numbers, to transfer data from the time domain to the frequency domain. "The new NIST method is, in effect, a Fourier transform for uncertainty," says NIST physicist Paul Hale.

Although the new method was developed for common lab test instruments, it also may have applications in measuring other types of waveforms, such as those generated in electrocardiograms for medical testing, ultrasound diagnostics of structural defects and failures, speech recognition, seismology and other remote sensing activities.

More information: P. Hale, A. Dienstfrey, J.C.M. Wang, D.F. Williams, A. Lewandowski, D.A. Keenan and T.S. Clement. Traceable waveform with a covariance-based uncertainty analysis. IEEE Transactions on Instrumentation and Measurement. Vol. 58, No. 10. Oct.

Source: National Institute of Standards and Technology (news : web)

Explore further: New method improves timing in oscilloscopes

Related Stories

New method improves timing in oscilloscopes

May 19, 2005

A new method for correcting common timing errors in high-speed oscilloscopes has been developed by researchers at the National Institute of Standards and Technology (NIST). The method improves the accuracy and clarity of ...

New NIST Method Improves Accuracy of Spectrometers

June 16, 2005

Measurements of the intensity of light at different wavelengths can be made more accurately now, thanks to a new, simple method for correcting common instrument errors. The new method, developed by researchers at the National ...

Road to AC voltage standard leads to important junction

July 20, 2006

After 10 years of research, the National Institute of Standards and Technology (NIST) has unveiled the world's first precision instrument for directly measuring alternating current (AC) voltages. The instrument is being tested ...

NIST antenna calibrations extended to 60-110 GHz

May 25, 2007

The National Institute of Standards and Technology (NIST) has developed a new "tabletop" sized facility to improve characterization of antennas operating in the 60 to 110 gigahertz (GHz) frequency range. This extended frequency ...

Recommended for you

A quantum of light for materials science

December 1, 2015

Computer simulations that predict the light-induced change in the physical and chemical properties of complex systems, molecules, nanostructures and solids usually ignore the quantum nature of light. Scientists of the Max-Planck ...

Quantum dots used to convert infrared light to visible light

December 1, 2015

(—A team of researchers at MIT has succeeded in creating a double film coating that is able to convert infrared light at modest intensities into visible light. In their paper published in the journal Nature Photonics, ...

Test racetrack dipole magnet produces record 16 tesla field

November 30, 2015

A new world record has been broken by the CERN magnet group when their racetrack test magnet produced a 16.2 tesla (16.2T) peak field – nearly twice that produced by the current LHC dipoles and the highest ever for a dipole ...

1 comment

Adjust slider to filter visible comments by rank

Display comments: newest first

1 / 5 (1) Oct 07, 2009
Electron action-reaction within the living cell
would be of IMMENSE value in solving mysteries of
gene programing, mitochondria function, mitosis in
normal and malignant modes, "gene" transcription, etc.! A family of wave-forms decoded -WOW!

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.