2/18/2004 Introduction to Engineering Electronics STOLEN FROM K. A. Connor 1 Lecture 6 Binary Counter Thinking Digitally

2/18/2004 Introduction to Engineering Electronics STOLEN FROM K. A. Connor 2 Henry Farny’s Song of the Talking Wire

2/18/2004 Introduction to Engineering Electronics STOLEN FROM K. A. Connor 3 2 Minute Quiz Name_______ Sec_______Date_______ Code Example: PWM Question:

2/18/2004 Introduction to Engineering Electronics STOLEN FROM K. A. Connor 4 Joseph Henry & the Telegraph Albany Academy Experiment Assisted Morse at Princeton 1 st Head of Smithsonian Unit of inductance: Henry

2/18/2004 Introduction to Engineering Electronics STOLEN FROM K. A. Connor 5 Morse Code Simple sequences of short and long clicks to represent letters and numbers Easier to generate than sound Easier to distinguish than sound

2/18/2004 Introduction to Engineering Electronics STOLEN FROM K. A. Connor 6 UPC Codes 0 = = = = = = = = = = Bars come in four widths Start is (black- white-black) The zero is (space-bar-space-bar). The four is (space-bar-space-bar). The three is (space-bar-space-bar). The next three zeros are (space-bar-space-bar). In the middle there is a standard (space-bar- space-bar-space), which is important because it means the numbers on the right are optically inverted! The one is (bar-space-bar-space). The stop character is a (bar-space-bar).

2/18/2004 Introduction to Engineering Electronics STOLEN FROM K. A. Connor 7 Computer Number System Examples From Computer Science I binary number B 5 C 5 9 C F 6 equivalent base 10 value for each group of 4 consecutive binary digits (bits) corresponding hexadecimal (base 16) digit B5C59CF6 equivalent hexadecimal number

2/18/2004 Introduction to Engineering Electronics STOLEN FROM K. A. Connor 8 Communicating With Pulses PCM: Pulse Code Modulation

2/18/2004 Introduction to Engineering Electronics STOLEN FROM K. A. Connor 9 PCM: Pulse Code Modulation

2/18/2004 Introduction to Engineering Electronics STOLEN FROM K. A. Connor 10 PWM: Pulse Width Modulation Signal is compared to a sawtooth wave producing a pulse width proportional to amplitude

2/18/2004 Introduction to Engineering Electronics STOLEN FROM K. A. Connor 11 Optical Receiver Receiver detects pulses of light Pulses are amplified and partly averaged by 741 op- amp (volume adjusted with the pot)  Higher frequencies still in signal cannot be heard Signal is increased by 386 audio amp 386 audio amp drives the speaker

2/18/2004 Introduction to Engineering Electronics STOLEN FROM K. A. Connor 12 Optical Transmitter Audio signal changes thresholds for 555 timer producing a type of pulse width modulation of the light from the LED.

2/18/2004 Introduction to Engineering Electronics STOLEN FROM K. A. Connor 13 Signals from Audio Remote 3.5 x 20 = 70ms or 14Hz 4 x 500 = 2000us or 500Hz 2 x 100 / 9 = 23us or 43kHz Mostly hear higher frequencies in pulses

2/18/2004 Introduction to Engineering Electronics STOLEN FROM K. A. Connor 14 Binary Numbers = 183

2/18/2004 Introduction to Engineering Electronics STOLEN FROM K. A. Connor 15 Binary Counter Animations showing counter operation Counter for lab

2/18/2004 Introduction to Engineering Electronics STOLEN FROM K. A. Connor 16 Typical Output for Binary Counter Note how the Q outputs form 4 bit numbers

2/18/2004 Introduction to Engineering Electronics STOLEN FROM K. A. Connor 17 Digital Pulses Function generator produces a 1kHz sinusoidal voltage. 1v peak-to-peak (pp)

2/18/2004 Introduction to Engineering Electronics STOLEN FROM K. A. Connor 18 Digital Pulses Switch to a square wave at 1kHz. Still 1v pp

2/18/2004 Introduction to Engineering Electronics STOLEN FROM K. A. Connor 19 Digital Pulses Add a 0.5 volt offset so that the square wave goes from 0 volts to 1 volt

2/18/2004 Introduction to Engineering Electronics STOLEN FROM K. A. Connor 20 Digital Pulses Now the duty cycle is adjusted to 20% to see what a single digital pulse looks like.

2/18/2004 Introduction to Engineering Electronics STOLEN FROM K. A. Connor 21 Pulses on a Transmission Line Pulses propagate down transmission lines at the speed of light. They reflect off of the load if the load is not the same impedance as the line. Lines, sources and loads must be matched. Cable TV lines are 75 ohms. Cables in the lab are typically 50 ohms. From Matlab

2/18/2004 Introduction to Engineering Electronics STOLEN FROM K. A. Connor 22 What Can Be Done With PWM? Question: What happens if voltages like the ones above are connected to a light bulb? (4 th 2 Minute Quiz Question) Low Duty Cycle Medium Duty Cycle High Duty Cycle

2/18/2004 Introduction to Engineering Electronics STOLEN FROM K. A. Connor 23 What Can Be Done With PWM? Average power can be controlled Average flows can also be controlled by fully opening and closing a valve with some duty cycle

2/18/2004 Introduction to Engineering Electronics STOLEN FROM K. A. Connor 24 What About Analog Modulation? AM: Amplitude Modulation FM: Frequency Modulation

2/18/2004 Introduction to Engineering Electronics STOLEN FROM K. A. Connor 25 Other Coding Applications Cryptography Image Compression  JPEG (Joint Photographic Expert Group)  GIF (Graphics Interchange Format)  TIFF (Tagged Image File Format)  MPEG (Compression of Motion Video)  Most use Discrete Cosine Transform method

2/18/2004 Introduction to Engineering Electronics STOLEN FROM K. A. Connor 26 Image Compression 24 bpp original (bits per pixel) Top: JPEG Bottom: JPEG2K 2 bpp0.5 bpp

2/18/2004 Introduction to Engineering Electronics STOLEN FROM K. A. Connor 27 2 Minute Quiz ANSWERS Code Example: MORSE, UPC Code Example: BINARY Code Example: PWM PWM Question: The longer the duty cycle, the longer the light bulb is on and the brighter the light

2/18/2004 Introduction to Engineering Electronics STOLEN FROM K. A. Connor 28 Where Will You See This Material Again? 555 Timer – IEE Lab 6 Digital Counter – IEE Lab 7 Counters: ECSE Computer Components and Operations, ENGR-2350 Introduction to Embedded Control Signals and Transforms: ECSE-2410 Signals and Systems Pulse Width Modulation: Embedded Control, ECSE/EPOW-4080 Semiconductor Power Electronics Pulses on Transmission Lines: ECSE-2100 Fields and Waves I