1 / 22

Measuring Noise

Measuring Noise. Presented By: Kelly McKirahan Colorado School of Mines. Mentor: Dr. Dragana Popovic. Outline. What is Noise? Common types of noise The HP35665A Dynamic Signal Analyzer Thermal Noise Boltzmann’s Constant Second Spectra The differences between Rock and Classical Music.

winda
Download Presentation

Measuring Noise

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Measuring Noise Presented By: Kelly McKirahan Colorado School of Mines Mentor: Dr. Dragana Popovic

  2. Outline • What is Noise? • Common types of noise • The HP35665A Dynamic Signal Analyzer • Thermal Noise • Boltzmann’s Constant • Second Spectra • The differences between Rock and Classical Music

  3. General Information • What is Noise? • General. Random changes or fluctuations of some parameter over time. • Where can you find noise? • Everywhere. • Price on stock exchange • Floods on the River Nile • Earthquakes in California • Transistors European Space Agency. Nile River Time Series. http://search.msn.com/images/details.aspx?q=nile+river&color=both&size=1p&ht=384&wd=512&tht= 96&twd=128&su=http%3a%2f%2fearth.esa.int%2friverandlake%2fsamples%2fsamples_africa_aswandam_img4.htm&iu=http%3a%2f%2fearth.esa.in t%2friverandlake%2fsamples%2flocations%2faswandam%2fimages%2fnile_height_diff_f.png&tu=http%3a%2f%2fimages.picsearch.com%2fis%3f18 41053082687&sz=11 Egyptians. The Story of the Nile. http://search.msn.com/images/details.aspx?q=nile+river&color=both&size=1p&ht=146&wd=196&tht=95&twd=128&su= http%3a%2f%2fwww23.thdo.bbc.co.uk%2fhistory%2fancient%2fegyptians%2fnile_02.shtml&iu=http%3a%2f%2fwww23.thdo.bbc.co.uk%2fhistory%2fa ncient%2fegyptians%2fimages%2fnile_01.jpg&tu=http%3a%2f%2fimages.picsearch.com%2fis%3f8501053249664&sz=12

  4. Common Types of Noise • White Noise • Johnson-Nyquist / Thermal Noise • Pink Noise, excess noise • Shot Noise

  5. What Is Johnson-Nyquist Noise? • Observed by Johnson in 1927 • Theory completed in 1928 by Nyquist • The noise stems from the thermal movement of the electrons. • All electrical components generate noise. • The noise increases as temperature increases. • Johnson noise could be used as a thermometer. J.B. Johnson. Thermal Agitation of Electricity in Conductors. http://prola.aps.org/pdf/PR/v32/i1/p97_1

  6. e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- Johnson-Nyquist Noise Voltage

  7. Sine Signal Log Noise Power (dB) Frequency (kHz) Voltage • Spectrum: Signal decomposed into a sine wave. Time (ms)

  8. White Noise • Consists of equal amounts of all frequencies. Voltage Time (ms)

  9. White Noise • Consists of equal amounts of all frequencies. • The power is independent of frequency. Voltage Time (ms) Noise Power The electromagnetic spectrum. http://imagers.gsfc.nasa.gov/ems/visible.html Frequency (kHz)

  10. Pink Noise • Distinguishable by larger fluctuations in the lower frequencies. Voltage Time (ms)

  11. Pink Noise • Distinguishable by larger fluctuations in the lower frequencies. • Power spectrum is inversely proportional to frequency, 1/f. Voltage Time (ms) Noise Power The electromagnetic spectrum. http://imagers.gsfc.nasa.gov/ems/visible.html Frequency (kHz)

  12. Shot Noise • Occurs because electric charge is quantized. • Distinguishable from Johnson-Nyquist Noise because noise of the electric current is included. The Blue Ridge Parkway Foundation. http://search.msn.com/images/details.aspx?q=Blue+ Ridge+Parkway&color=both&size=1p&ht=240&wd=370&tht=83&twd=128&su=http%3a%2f% 2fwww.brpfoundation.org%2findex.php&iu=http%3a%2f%2fwww.brpfoundation.org%2fimages %2fHomePhoto.jpg&tu=http%3a%2f%2fimages.picsearch.com%2fis%3f228759526445&sz=146 Blue Ridge Parkway. http://www.georgiazclub.com/photos/blue2.jpg

  13. e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- Shot Noise A A

  14. Project HP35665A Motivation: To create a LabVIEW program to interface the computer with the dynamic signal analyzer.

  15. Thermal Noise • Motivation: To measure Boltzmann’s constant at three specified temperatures using electronic noise. • Temperatures: • Room Temperature (~ 300K) • Liquid Nitrogen (77K) • Liquid Helium (4.2K) • Result: 1.88E-23 J/K • Boltzmann’s Constant: 1.381E-23 J/K Log d<V2> Log T Riedon. “Precision Metal Film Resistors,” http://search.msn.com/images/details.aspx?q=metal+film+resistors&color=both&size=1p&ht=116&wd=200&tht=74&twd=128&su=http%3a%2f%2fwww.riedon.com%2fmf.htm&iu=http%3a%2f%2fwww.riedon.com%2fimages%2fmf_series.gif&tu=http%3a%2f%2fimages.picsearch.com%2fis%3f603548391686&sz=5

  16. Constructing a Second Spectra Step 1: Input a signal for analysis. HP35665A Step 2: The HP35665A DSA performs a Fourier Transform on the signal and outputs data.

  17. Noise Power Frequency (kHz) Step 3: Use LabVIEW interface to collect the data. Noise Power Number of Points Step 4: Look at a specific frequency bandwidth of the signal.

  18. Noise Power Frequency (kHz) Step 5: Average the frequency bandwidth over a number of spectrums. Noise Power Noise Power Frequency (kHz) Frequency (kHz) Plot the power spectrum of the average. This is the “noise of the noise.” Step 6: NoisePower Number of Points

  19. Step 7: Lastly, the Fourier transform is performed on the power spectrum to obtain the second spectra. Weezer “Haunt Your Every Day” Second Power Spectra Second Frequency

  20. Second Spectra Slope = -0.0305 Slope = -1.56 Slope = -0.674 Second Power Spectra Slope = -1.36 Second Spectra Frequency

  21. Conclusion • The analyzer was used to investigate different audio signals. • Speech has a white second spectrum. • Classical music has a pink second spectrum. • Rock music is between classical music and speech. • The greater impression on the listeners the pinker the second spectra.

  22. Special Thanks To • Dr. Dragana Popovic • Scholar ScientistScience, Condensed Matter / Experimental • Dr. Jan J. Jaroszynski • Visiting ScientistDirector's Office, Visitor's Program NSF NHMFL CIRL Staff Ms. Gina C. LaFrazza Assistant Director Director's Office, Center for Integrating Research & Learning • Ms. Ivana Raicevic • Graduate Research AssistantScience, Condensed Matter / Experimental • Dr. Marko Dragosavac • Postdoctoral AssociateScience, Condensed Matter / Theory

More Related