ECE 498 CB
LEDs and Solar Cells
Spring 2016
HW # 5
(10 pts) Read the assigned chapter titled Light and Color. Summarize your understanding in 5 sentences
(150 words).
(30 pts) According to quantum mechanics, an electromagnetic radiation of frequency can b
UNIVERSITY OF ILLINOIS AT URBANA-CHAMPAIGN
Department of Electrical and Computer Engineering
ECE 498MH Signal and Image Analysis
Homework 1
Fall 2013
Assigned: Friday, September 6, 2013
Due: Friday, September 13, 2013
Reading: McClellan & Schafer 2.1-2.5
UNIVERSITY OF ILLINOIS AT URBANA-CHAMPAIGN
Department of Electrical and Computer Engineering
ECE 498MH Signal and Image Analysis
Homework 2
Fall 2013
Assigned: Friday, September 13, 2013
Due: Friday, September 20, 2013
Reading: Signal Processing First (SP
UNIVERSITY OF ILLINOIS AT URBANA-CHAMPAIGN
Department of Electrical and Computer Engineering
ECE 498MH Signal and Image Analysis
Homework 3
Fall 2013
Assigned: Friday, September 20, 2013
Due: Friday, September 27, 2013
Reading: Signal Processing First (SP
Wireless Medium Access Control
Romit Roy Choudhury
Wireless Networking Lectures
University of Illinois at Urbana Champaign
1
Wired Vs Wireless Media Access
Both are on shared media.
Then, whats really the problem ?
2
The Channel Access Problem
Multiple no
Extracting Optimal
Performance from
Dynamic Time Warping
Abdullah Mueen
mueen@unm.edu
Eamonn Keogh
eamonn@cs.ucr.edu
We will start at 8:10am, to allow stragglers to find us. In the meantime, download:
www.cs.unm.edu/~mueen/DTW1.pdf or ./DTW1.pptx and ./DT
Smartphone Positioning Systems
Romit Roy Choudhury
Smartphone Positioning Systems:
The problem space
Motivation
Sudden growth in smartphone industry
Localization technology caught unprepared
Industry viewing location as address for content
delivery
Motiv
Communication
through Physical
VibrationNirupam Roy
ECE498RR Guest Lecture
UIUC, October 5, 2016
Short range communication:
a new need of this
decade
Short range communication:
a new need of this
decade
Emerging technologies for
short range
Capacity
Drivi
Rate Control in Wireless Networks
Romit Roy Choudhury
1
Recall 802.11
RTS/CTS + Large CS Zone
Alleviates hidden terminals, but trades off
spatial reuse
E
CTS
A
B
C
RTS
F
D
2
Recall Role of TDMA
3
Recall Beamforming
Omni
OmniCommunication
Communication
D
Unsupervised Indoor Localization
(UnLoc)
1
Where am I in a hotel, mall, office, cruise ship?
2
GPS
GPS satellite
Why not outdoor localization technology?
3
Wi-Fi
(x1,y1)
(x2,y2)
(x3,y3)
AP 1: -65
AP 2: -50
AP 3: -80
AP 4: -85
AP 1: -60
AP 2: -62
AP 3: -55
UNIVERSITY OF ILLINOIS AT URBANA-CHAMPAIGN
Department of Electrical and Computer Engineering
ECE 498MH Signal and Image Analysis
Solutions 5
Fall 2013
Assigned: Friday, October 11, 2013
Due: Friday, October 18, 2013
Reading: SPF Chapter 7 and Sections 8.1
UNIVERSITY OF ILLINOIS AT URBANA-CHAMPAIGN
Department of Electrical and Computer Engineering
ECE 498MH Signal and Image Analysis
Homework 7
Fall 2013
Assigned: Friday, November 1, 2013
Due: Friday, November 8, 2013
Reading: SPF Chapter 12-3 covers almost
HW 4
Yue Wang yuewang3
Problem4.1
Impulse response can be derived through
Thus, impulse response can be expressed as following:
Problem4.2
a)
solution:
=-
b)
solution:
HW 4
Yue Wang yuewang3
I cannot find a simplified version for this problem.
c)
solution
Michael Diehl
MTDIEHL2
ECE 498CB
Fri, 2/12/2016
Prof. Bayram
1)
a. Development of the Blue Light-Emitting Diode
In the 1980s GaN was discoraged from study because of a lack of suitable
substrate. Prof. Nakamura modified his commercial MOCVD, developing th
ECE 498 CB
LEDs and Solar Cells
Spring 2016
Michael Diehl
MTDIEHL2
HW #4
Due 2/19/2016
HW # 4
(10pts) Read the magazine article titled LED lighting makes new demands on color measurements at
http:/digital.laserfocusworld.com/laserfocusworld/201601?sub_id=
1)
a. Development of the Blue Light-Emitting Diode
In the 1980s GaN was discoraged from study because of a lack of suitable
substrate. Prof. Nakamura modified his commercial MOCVD, developing the
Two-Flow MOCVD, while studying GaN in order to publish 5 sc
Yue Wang,
HW6
Problem 6.1
a)
b)
The answer is REAL value!
c) First zeros of :
Because is an even function, when , the first zero-crossing at both x-axis is
d) =
Problem 6.2
Magnitude and phase of the signal:
Zero-padded to 1024 samples:
Yue Wang,
HW6
The
ECE498MH
HW9, Yue Wang yuewang3
Problem 1
a)
When
When
b)
c)
d) Proof:
When n
is true because:
When n=0
In summary, is true.
Problem 2
I changed the final synthesized signal to 8000/28=285.71Hz which is closer to my voice
frequency (300Hz). The final LPC
ECE498MH-HW 8
Yue Wang, yuewang3
Problem 1
x(t) = cos 29000t)
(
a)
[] = cos (29000 10000) = cos(1.8) = cos(2 1.8) = cos 0.2)
(
b) Because [] is discrete in time, it will have energy at 0.2 + 2 and 0.2 + 2
where ~
Example of some frequencies are:
3.8, 2.2,
ECE498MH-HW 8
Yue Wang, yuewang3
Problem 1
a)
b) Because is discrete in time, it will have energy at and where
Example of some frequencies are:
Thus, after recovering the signal using a D/A, s frequencies in Hz:
c) To get signal , we need to select a low
ECE 498MH
Problem 10.1
a)
Solution 1:
Solution 2:
b)
Yue Wang,
HW10
ECE 498MH
Yue Wang,
HW10
c)
If v[n] and s[n] are not correlated, then
Where and are the power spectrum of the signal and the noise respectively. They are from part
a) and part b)
Problem
Yue Wang,
HW6
Problem 5.1
a) Because the difference equation has not only x[n-d], but also y[n-d], thus, this is
an IIR filter.
b)
c) Apply Z-transformation on the difference equation:
d) Zeros:
and
Poles:
and
Using Matlab:
> b=[1 0.5 0.25];
> a=[1 -.5 .2
ECE/CS 498rc Programming Assignment 2:
Computing Moving Direction using Smartphone Sensors
Due: 9thOct, 2016
1
Objective
Computing the walking trajectory of a user with the smartphone sensors (e.g., accelerometer, compass,
gyroscope, barometer, etc.), and
Indoor Semantic Localization
(SurroundSense)
1
Many emerging location based apps
do not care about the physical location
GPS: Latitude, Longitude
Instead, they need the users logical
location
Starbucks,
RadioShack, Museum,
Library
Why not convert from
Phy
Black-body radiation
In physics, a black body is an object that absorbs all electromagnetic radiation that falls onto it.
No radiation passes through it and none is reflected, yet it theoretically radiates every possible
wavelength of energy.
The black-bo
7 OCTOBE R 2014
Scientific Background on the Nobel Prize in Physics 2014
EFFICIENT BLUE LIGHT-EMITTING DIODES LEADING
T O B R I G H T A N D E N E RG Y - S AV I N G W H I T E L I G H T S O U RC E S
compiled by the Class for Physics of the Royal Swedish Aca
Depletion width for p-n junctions and metalsemiconductor contacts
Depletion width in pn junctions
The following equations were used for the plots:
Vbi =
kT N A N D
ln
e ni 2
J. M. Shah and E. F. Schubert
WD =
1
2Vbi
e
1
1
+
NA ND
xn =
2Vbi
N
eN D 1 +
Ray tracing and ABCD matrix
Optics, Eugene Hecht, Chpt. 6
Basics of ray tracing
Consider 2D projection
Ray uniquely defined by position and angle
Make components of vector
Paraxial approximation - express angle as slope = y
= y
y
z
Example: Propagat
ECE/CS 498rc
Programming Assignment 1: Exploring Multi-Modal Sensing on Smartphones
Due: Sunday, Sept 11th, 2016
1
Objective
The goal of this assignment is to get familiar with the smartphones multi-modal sensing capability. This assignment will introduce
Maximum Efficiency of an Ideal Solar Cell Containing
One and Two Intermediate Bands
Steven Jenks
May 30, 2008
Abstract
Introducing intermediate band(s) within the energy gap of the semiconductor
could possibly increase efficiencies of solar cells. Photons