Printer Friendly
The Free Library
23,375,127 articles and books


FIRST MEASUREMENTS OF AC-COUPLED JOSEPHSON WAVEFORM SYNTHESIZER.

NIST researchers have completed preliminary rms voltage measurements of the Josephson waveform synthesizer when it is biased using a new ac-coupled technique. AC coupling allows us to use distributed arrays of more than 4000 junctions that have larger output voltage as compared to the previously used lumped arrays with only 250 junctions. More importantly, this technique allows researchers to ground the Josephson array output voltage so that it can be directly measured using low impedance instruments, such as spectrum analyzers and thermal voltage converters. Direct connection to measurement instrumentation is required for optimum performance of calibrations because it avoids the possible gain and distortion errors that can be induced by intermediate amplifiers. NIST researchers have made the first spectral measurements of a directly coupled array and found that harmonic distortion was more than 80 dB below the amplitude of synthesized fundamental frequencies of I kHz and 50 kHz. This measurement was likely limited by distortion in the spectrum analyzer. They also used a thermal transfer standard to compare the rms voltages of synthesized sine waves at 3 kflz, 10 kHz, 20 kHz, and 50 kHz with a synthesized 1 kHz sine wave. The measured Type A uncertainty for each comparison was no more than one-tenth that of previous comparisons using lower voltage lumped arrays.
COPYRIGHT 2000 National Institute of Standards and Technology
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 2000, Gale Group. All rights reserved. Gale Group is a Thomson Corporation Company.

 Reader Opinion

Title:

Comment:



 

Article Details
Printer friendly Cite/link Email Feedback
Publication:Journal of Research of the National Institute of Standards and Technology
Article Type:Brief Article
Geographic Code:1USA
Date:Nov 1, 2000
Words:214
Previous Article:IMPROVED SPECTRAL IRRADIANCE SCALE OFFERED BY NIST.
Next Article:NIST COLLABORATION USES MICROGRAVITY TO IMPROVE PROTEIN CRYSTAL GROWTH.
Topics:



Related Articles
NEW TECHNIQUE FOR A HIGHER VOLTAGE AC JOSEPHSON STANDARD.
100 mV PEAK OUTPUT DEMONSTRATED FOR THE JOSEPHSON WAVEFORM SYNTHESIZER.
UNIFORM Ti-BARRIER JOSEPHSON JUNCTION ARRAYS FOR AC JOSEPHSON VOLTAGE STANDARD.
The ampere and electrical standards.
Precision ultrasonic wave measurements with simple equipment.
Quantized voltage steps in arrays of stacked Josephson junctions demonstrated. (News Briefs).
NIST researchers demonstrate stacked Josephson junction arrays using [MoSi.sub.2] barriers. (General Developments).
Optimizing interconnect performance with eye diagrams: eye measurements can be used as an interconnect optimization tool with frequency, time and...

Terms of use | Copyright © 2014 Farlex, Inc. | Feedback | For webmasters