Today TBA Tomorrow Good Friday SE-2811 Slide design: Dr. Mark L. Hornick Content: Dr. Hornick Errors: Dr. Yoder 1 SE3910 Week 5, Class 3

Ex: C/C++ (Review) Why do we have both.h and.cpp file extensions for C++? Why not just have.cpp (like.java for Java classes)? Answer these questions: 1. What should you put into a class’s.h file? 2. What should you put into a class’s.cpp file? [Note: On next lab, use.hpp and.cpp instead of.h and.cpp] SE-2811 Dr.Yoder 2

Compiling and Linking Compiling Converting individual.c or.cpp file to object code Linking Combining multiple object (.o) files into an excecutable (usually without extension, or.exe on Windows) SE-2811 Dr.Yoder 3

Ex: C/C++ Circle the link-time errors. Box the compile- time syntax error warning: implicit declaration of function `...' point.m:40: error: ‘mypoint’ undeclared (first use in this function) parse error before `...‘ collect2: ld returned 1 exit status undefined reference to `filterText' /usr/lib/crt1.o(.text+0x18): undefined reference to `main ' SE-2811 Dr.Yoder 4

Network Latency with resmon.exe SE-2811 Dr.Yoder 5

Signals as sums of sine-waves SE Dr. Josiah Yoder Slide style: Dr. Hornick Much Material: Dr. Schilling 6 sSquareWave.html lides/SlideFiles.html

SE Dr. Josiah Yoder Slide style: Dr. Hornick Much Material: Dr. Schilling 7

Units: dB What is a decibel? A tenth of a bel What is a bel? The log 10 of some ratio. e.g. signal power / noise power X dB = 10 log 10 (Y) X – in units of dB Y – simple ratio (unitless) 8

dB examples dB 50 dB100, dB1,000 0 dB1 -30 dB dB SE-2811 Dr.Yoder 9

Channel capacity SE Dr. Josiah Yoder Slide style: Dr. Hornick Much Material: Dr. Schilling 10

In-class exercise The old analog TV channels had a bandwidth of 6MHz Supposing a SNR of 50 dB, what is the maximum possible bit-rate? SE Dr. Josiah Yoder Slide style: Dr. Hornick Much Material: Dr. Schilling 11

In-class Activity: What is the data rate of classic NTSC television (as digital stream)? Store color with special scheme so only two bytes required per pixel, on average 720x480 30/1.001 fps Follow up: If compressed to 25MiB/s (or 25MB/s) what is the compression ratio? SE Dr. Josiah Yoder Slide style: Dr. Hornick Much Material: Dr. Schilling 12

The Stroboscopic Effect Have you ever noticed something that is in motion seem to stop? SE Dr. Josiah Yoder Slide style: Dr. Hornick Much Material: Dr. Schilling 13

The Stroboscopic Effect (Aliasing) ns/7/77/Propeller_strobe.ogv ns/7/77/Propeller_strobe.ogv ns/e/ef/The_wagon-wheel_effect.ogv ns/e/ef/The_wagon-wheel_effect.ogv SE Dr. Josiah Yoder Slide style: Dr. Hornick Much Material: Dr. Schilling 14

Safety See, e.g. “DC lamps must always be turned on when using any rotating machines” t-faculty-shop/machine-shop-rules SE Dr. Josiah Yoder Slide style: Dr. Hornick Much Material: Dr. Schilling 15

Aliasing 512/what-is-aliasing-and-anti-aliasing SE Dr. Josiah Yoder Slide style: Dr. Hornick Much Material: Dr. Schilling 16

More aliasing Single-Sensor Imaging: Methods and Applications for Digital Cameras, by Rastislav Lukac ms/showthread.php?t=14988 SE Dr. Josiah Yoder Slide style: Dr. Hornick Much Material: Dr. Schilling 17

Human eye Recall As little as 13ms Notice interruption As short as 16ms Single-ms duration looks as long as ms 10ms green followed by 10ms red May appear as single yellow stimulus SE Dr. Josiah Yoder Slide style: Dr. Hornick Much Material: Dr. Schilling 18

Ex: Why might you want to sample at a higher frame-rate than the 30fps? Be as professional as possible Avoid flame wars Have technical depth to back it Avoid sounding technical just to be cool SE Dr. Josiah Yoder Slide style: Dr. Hornick Much Material: Dr. Schilling 19

Ex: What are two ways we can avoid the stroboscopic effect in a video game simulation of a rotating wheel? SE Dr. Josiah Yoder Slide style: Dr. Hornick Much Material: Dr. Schilling 20

In-class Activity: Analog to digital bandwidth SE Dr. Josiah Yoder Slide style: Dr. Hornick Much Material: Dr. Schilling 21

In-class activity Suppose I have a band centered at 100 Mhz which is 1Mhz wide. What are the limits on this range? What is the wavelength of the center 1 Mhz signal speed of light = m / s speed in Cat-5 is 70% of this wavelength = time of period * velocity SE Dr. Josiah Yoder Slide style: Dr. Hornick Much Material: Dr. Schilling 22

Fiber-optic Transmission In fiber-optic transmission, signals are sent by transmitting various colors (or invisible) light down a fiber-optic channel The colors are separated at the other end Multiple fibers can be used Supposing that the same bandwidth rule applies, what bandwidth can be carried by the visible spectrum? ( nm) Use SNR of 4000 Hint: Convert wavelength to period/frequency SE Dr. Josiah Yoder Slide style: Dr. Hornick Much Material: Dr. Schilling 23

Muddiest Point Wait for the slides, or follow this link to answer both questions at once: SE-2811 Dr.Yoder 24

Muddiest Point Wait for the slides, or follow this link to answer both questions at once: SE-2811 Dr.Yoder 25

SE-2811 Dr. Josiah Yoder 26

SE-2811 Dr. Josiah Yoder 27

References EB: Derek Malloy, Exploring Beaglebone, Wiley, duction_to_gcc/gccintro_95.html theory.co.uk/docs/gccintro/gccintro_95.html c-compile-errors-in-an-basic-example-objc- program duction_to_gcc/gccintro_94.html SE-2811 Slide design: Dr. Mark L. Hornick Content: Dr. Hornick Errors: Dr. Yoder 28