2. Percent Errir A Quick Guide to Figuring Out By Just How Much You Missed the Target …Error

3. The Suspects Do you recognize these?

4. What can you tell from fingerprints? Having a certain number of points on a fingerprint means that you can find out who committed a crime.

5. Did You Know? Someone from the University of California figured out a way to find people with their computers, just by using an error we’ll discuss today. Computer Tracking Story

6. Question What is the most important part of ANY electronic device? Answer: the clock is the most important part of ANY electronic device.

7. How often something happens is called its… Hint: The answer starts with an ‘f.’ Answer: How often something happens is called its frequency ( f.)..).

8. Problem… Most test equipment in engineering makes important measurements using time, frequency.

9. Problem… How do we get from frequency (how often something happens) to time (how long something takes to happen)? frequency ( f ) f 1f1f = T (Period) = time

10. What is a Clock? In electronics, the CLOCK CLOCK like the HEART HEART in a person. The clock tells other parts of your iPod or laptop to do something at a certain time.

11. What Does a Clock Have to Do with Error? Unfortunately, just like some people have an arrhythmia (heart misses a beat sometimes), electronics can miss a beat, too.

12. In general terms, the people who make electronics call this “missing a beat” jitter, where the real signal isn’t quite like the expected signal. There’s a delay. One measurement that is similar jitter is skew.

13. What Does a Clock Look Like? A clock is an integrated circuit. Integrated circuits come in various packages. QFN TSSOP SSOP

14. This is what a Clock Signal Should Look Like. Since these numbers are small, we’ll keep everything in units of picoseconds (10 -12 sec) to avoid using scientific notation…for now. Really small numbers are good!

15. Which one of these pictures shows a BAD Clock Signal? The picture on the left shows that the waves are off by almost 200 picoseconds (2 x 10 -10 s). That’s a whopping 1.2%...a lot for electronics! The wave on the right is only off by 0.0001%.

16. Let’s take a closer look at the bad skew.

17. Let’s Look at Some Data. With all of these small numbers, there are maximum values allowed. If the biggest number allowed is 500 picoseconds (ps) for skew. Then, what would a difference of 197 ps mean to the signal – or your iPod? What error is there in the signal?

18. ___- 5.9700 ps___ _____ ? ______ __.8800 ps__ Let’s Determine the Difference. Two waveforms have difference times associated with them in picoseconds (ps). What is the difference between the numbers in ps? 722.40 ps 754.15 ps 719.64 ps 745.63 ps - 721.52 ps = - 760.12 ps = -718.41 ps = - 739.14 ps = _____ ? ______ ____1.2300 ps_____ ____6.4900 ps_____

19. Let’s Determine Percent Difference. Signal 1 Signal 2 723.25 ps725.12 ps Use one of these equations to find the percent error: a.% Error = |Expected Value - Actual Value| x 100% Expected Value b. % Error = |Difference Between Signal Frequencies| x 100 Expected Value -0.25856%

20. Practice Time!

21. Sources of Information Pictures 1.Fingerprints: http://www.cse.msu.edu/biometrics/fingerprint.html http://www.cse.msu.edu/biometrics/fingerprint.html 2.iPod: http://eng.hebus.com/gifs/hobbies-leisures/computers/gal5817-page1.html http://eng.hebus.com/gifs/hobbies-leisures/computers/gal5817-page1.html 3.Laptop: http://www.orcaresearch.org/images/LAPTOP.png http://www.orcaresearch.org/images/LAPTOP.png 4.http://2.bp.blogspot.com/_aw_cCbK3XzY/ShGAPndceSI/AAAAAAAAB6s/tn7eSfuk LiA/s400/cell+phone.png http://2.bp.blogspot.com/_aw_cCbK3XzY/ShGAPndceSI/AAAAAAAAB6s/tn7eSfuk LiA/s400/cell+phone.pnghttp://2.bp.blogspot.com/_aw_cCbK3XzY/ShGAPndceSI/AAAAAAAAB6s/tn7eSfuk LiA/s400/cell+phone.png 5.Clock: http://www.ncstatefair.org/2009/Competitions/WebGraphic/2008winners/HH030/ 538_JOEYMOORE2-HH030/clock_animated.gif http://www.ncstatefair.org/2009/Competitions/WebGraphic/2008winners/HH030/ 538_JOEYMOORE2-HH030/clock_animated.gif http://www.ncstatefair.org/2009/Competitions/WebGraphic/2008winners/HH030/ 538_JOEYMOORE2-HH030/clock_animated.gif 6.SSOP: http://rocky.digikey.com/weblib/Linear%20Tech/Web%20Photo/161-16- SSOP.jpg http://rocky.digikey.com/weblib/Linear%20Tech/Web%20Photo/161-16- SSOP.jpghttp://rocky.digikey.com/weblib/Linear%20Tech/Web%20Photo/161-16- SSOP.jpg 7.TSSOP: http://media.digikey.com/photos/IDT,%20Integrated%20Device%20Technology/IC S9DB1200CGLFT.JPG http://media.digikey.com/photos/IDT,%20Integrated%20Device%20Technology/IC S9DB1200CGLFT.JPG http://media.digikey.com/photos/IDT,%20Integrated%20Device%20Technology/IC S9DB1200CGLFT.JPG 8.MLF: http://media.digikey.com/photos/IDT,%20Integrated%20Device%20Technology/mp c9865vm.JPG http://media.digikey.com/photos/IDT,%20Integrated%20Device%20Technology/mp c9865vm.JPG http://media.digikey.com/photos/IDT,%20Integrated%20Device%20Technology/mp c9865vm.JPG Skew Fingerprinting Story: 1.http://www.theinternetpatrol.com/track-any-computer-on-the-internet-using- its-clock-skew-fingerprint/ http://www.theinternetpatrol.com/track-any-computer-on-the-internet-using- its-clock-skew-fingerprint/http://www.theinternetpatrol.com/track-any-computer-on-the-internet-using- its-clock-skew-fingerprint/ 2. 2.Fingerprinting Lesson Plans: http://sciencespot.net/Pages/classforsci.html#fiingerprint http://sciencespot.net/Pages/classforsci.html#fiingerprint Oscilloscope Screen Shots 1. Integrated Device Technology internal records