Hello Time-Nuts fans, >From "Phase Noise Measurements and its Limitations", Synergy Microwave Corporation:
https://synergymwave.com/articles/2013/04/full_article.pdf "There is an optimum condition and some of the measurements showing -190dBc/Hz do not seem to match the theoretical calculations. The correlation allows us to look below KT, but the noise contribution below KT is as useful as finding one gold atom in your body's blood. This gold atom has no contribution to your system." This is not accurate or complete. 1. The human body is composed of many elements. One of the lesser know elements is actually Gold. An average person's body weighing 70 kilograms would contain a total mass of 0.2 milligrams of gold. Gold plays a vital role in health and maintenance of the joints. Also, being a good conductor of electricity, it actually helps in transmitting electrical signals throughout the body. (including the brain - MRM) https://www.indiatoday.in/education-today/gk-current-affairs/story/gold-body-345917-2016-10-10 2. The Atomic weight of the Gold (Au) is = 196.97 (197g apprx.) The Avogadro's number in one mole are = 6.022X10^23 That means 6.022X10^23 atoms weigh 196.97 g. 1.0 g/ 196.97 g = 0.0051 mol So the number of atoms in one gram of gold are: 0.0051 x 6.022X10^23 = 3.057318373 x 10^21 https://brainly.in/question/6453418 3. 0.2 milligrams of gold is 3.05e21 * 0.0002 = 6.1e+17 atoms This is a very large number, but we can break it down to a more manageable number. The average human has a mass of about 62 kg, or 62,000 grams. That means the average volume of a human is 62,000 cubic centimeters, ignoring the weight of bones. So each cubic centimeter contains 62e3/6.1e17 = 1.016e-13 atoms of gold This is 10,160,000,000,000 atoms per cubic centimeter. So you have a very good chance of finding an atom of gold in your body. And it is vital to your health. 4. Here is a brief explanation of how cross-correlation works: "Understanding Phase Noise - the Cross Correlation Method" https://www.youtube.com/watch?v=Sf7qiysPFbQ 5. The benefit of cross-correlation depends on how long you are willing to wait. My recent quote of -220dBc/Hz was unrealistic. I do not know where I found that figure, but I will now set the story straight. From "TSP #162 Tutorial on Theory, Characterization & Measurement Techniques of Phase Noise" https://www.youtube.com/watch?v=SOHjFtw0sgo each 5db of improvement requires an order of magnitude increase in the number of correlations. dB 5 10 15 20 25 30 35 40 N 10 100 1000 1E4 1E5 1E6 1e7 1e8 So going from -180dBc/Hz to 220dBc/Hz would require 1e8 correlations. 6. Nobody would wait that long. But how many correlations do you need? A commonly accepted figure is your measurement noise floor has to be at least 10 dB below the noise you are trying to measure. We could pad that by 5 db, which would require 15 / 5 = 3 1e3 = 1000 correlations. That is not too bad. 7. It is interesting to note the Holsworth HA7062C Phase Noise Analyzer goes to a maximum of 1024 cross-correlations. 100 correlations (-10dB) takes 7 min, 9s at 10 MHz. https://holzworth.com/Portals/0/HA7062C_Web_Datasheet.pdf 8. Finally, "Frequency Signal Source's PN (Phase Noise) Measurements Challenges and Uncertainty", by Ulrich L. Rohde, has some very important information on cross-correlation errors. This file is at https://www.mrmonett.com/pdfs/2015-IFCS-Rohde-Oscillator-noise.pdf _______________________________________________ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.