New User Special Price Expires in

Let's log you in.

Sign in with Facebook


Don't have a StudySoup account? Create one here!


Create a StudySoup account

Be part of our community, it's free to join!

Sign up with Facebook


Create your account
By creating an account you agree to StudySoup's terms and conditions and privacy policy

Already have a StudySoup account? Login here

Special Topics Dyn. and Cont. AC Drives

by: Sidney Stehr

Special Topics Dyn. and Cont. AC Drives ECGR 6090

Sidney Stehr
GPA 3.51

Ivan Howitt

Almost Ready


These notes were just uploaded, and will be ready to view shortly.

Purchase these notes here, or revisit this page.

Either way, we'll remind you when they're ready :)

Preview These Notes for FREE

Get a free preview of these Notes, just enter your email below.

Unlock Preview
Unlock Preview

Preview these materials now for free

Why put in your email? Get access to more of this material and other relevant free materials for your school

View Preview

About this Document

Ivan Howitt
Class Notes
25 ?




Popular in Course

Popular in Electronics and Computer Technology

This 26 page Class Notes was uploaded by Sidney Stehr on Sunday October 25, 2015. The Class Notes belongs to ECGR 6090 at University of North Carolina - Charlotte taught by Ivan Howitt in Fall. Since its upload, it has received 25 views. For similar materials see /class/228998/ecgr-6090-university-of-north-carolina-charlotte in Electronics and Computer Technology at University of North Carolina - Charlotte.


Reviews for Special Topics Dyn. and Cont. AC Drives


Report this Material


What is Karma?


Karma is the currency of StudySoup.

You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!

Date Created: 10/25/15
thure 1 Illustrwmg Ttmerdomnm m Frequency Damn ofu Moweer Wave rgnzr T h v n n d m m M M vm mr H vm practrce we always use a mte ume penud when makmga measurement Founet transtormatrons can also be made from the frequency to the me domarn Ths case also spectral m m m V Ym 1 p example a square wave transformed to the frequency domarn and back agarn coum tum mto a sawtooth wave If phase were not preserved What is a Spectrum What tsa spectrumm the context Ufths discusswr A spectrum tsa a u a V under examrnau on The buttumrleft graph of a gure 1 shows the wave form of a complex m on Y a rndrcatron otthe reason why The rest of gure 1 shows our complex sagnal m both the s 1 h n r still showing Select Ref Level and change the value to one that shows the entire signal on the screen You should now have a screen that looks similar to Figure 2 nun mmquot smumnmmu mmma d LE mesa was Cummuws 0439 Single in mnhnue Fzgme 2 Example ween shot onOMHz reference signal sure to note the values displayed on the screen around the graph These are very useful for demmining what may need to be changed in order to better view a signal Also when on 39 mea Ilrement will also L quot39 r d on the fl In order to analyze this screen make use of the marker function by pressing the Marker button or pressing Peak Search Peak Search will automatically find the largest peak and place the marker at the location Measurement relative to this marker may now be making by selecting Delta under the Marker menu Notice that the delta measurement is displayed on the toprright portion of the graph You shouiu no 39 fviewing a i nal and have a better understanding of navigating the device 1 I L 391 Prmrrammin Examplesquot document found onthe A ilent it achcm m H o i o 0032df for a better understanding of other functions When sitting down with the spectrum analyzer become familiar with the front panel buttons and understand what each set does Pages 52754 of the Agilent document describe the function of each button or group of bunons on the front panel Chapter 5 of the Measurement Guide and Programming Examplesquot document A 39 39 39 39 39 39 covered in the previous paragraphs Chapter 5 then goes on to explain details on important analyzing techniques WIRELESS LAN SECURITY ISSUES By Priyanka Lingayat Priya Puthran WLAN 1 A network that connects devices in a small easily de ned area such as a room building or campus using highfrequency radio waves instead of wires as the communication medium 3 WLAN s operate at the speed ranging from 1 to 54Mbps with some manufacturers currently offering proprietary 108 Mbps solutions and security of the wireless access point is shared among everybody nearby so security issues eXist with WLANs that don t eXist for wired networks 3 80211 refers to specification developed by IEEE for WLAN It speci es an overtheair interface between a wireless client and a base station or between two wireless clients Standards Year Frequency Band Bandwidth Encoding Technique 5 Range Inter ference risks WLAN Standards 80211 80211a 1997 1999 24GHz 5GHz ISM UNII 2Mbps 54Mbps DSSSFH OFDM SS 60100 ft Low 80211b 1999 24GHz ISM 11Mbps DSSS 70150 ft High 80211g 2003 24GHz ISM 54Mbps OFDM 65 120 ft High 80211n 2006 24 300M bps Threats amp Vulnerabilities Ma1icious entities may gain unauthorized access to an organization s computer network through wireless connections bypassing any firewall protections Traffic sniffing Easier to perform on wireless than on traditional wired LANs SSID is always sniff able when stations associate to an AP Sensitive information that is not encrypted or is encrypted with poor cryptographic techniques and that is transmitted between two wireless devices may be intercepted and disclosed Denial of service DoS attacks may be directed at wireless connections or devices Malicious entities may steal the identity of legitimate users and masquerade on internal or external corporate networks Sensitive data may be corrupted during improper synchronization Malicious entities may be able to violate the privacy of legitimate users and be able to track their actual movements Data may be extracted without detection from improperly con gured devices Viruses or other malicious code may corrupt data on a wireless device and be introduced to a wired network connection Interlopers may be able to gain connectivity to network management controls and disrupt operations Original 80211 Security goals Authorization Verify that all mobile stations are authorized to access the network Privacy Implement security such that there is no privacy difference between wireless and wired LANs Maintain data privacy from all unauthorized stations Original 80211 Security Two authentication methods available Open system authentication Station 1 sends Service Set 1 SSID to station 2 Station 2 accepts or rejects station 1 based on knowledge of SSID APs can be configured to accept the broadcast SSID 39Thus allowing anyone to access the AP Shared key authentication Stations respond to an authentication challenge from an AP or other device AP sends a challenge to be encrypted by the station Station encrypts the challenge with shared key AP decrypts challenge and grants or denies authentication based on decryption results 80211 Security Standards WEP The Wired Equivalent Privacy protocol is used in 80211 networks to protect linklevel data during wireless transmission WPA WPA implements the majority of the IEEE 80211i standard and was intended as an intermediate measure to take the place of WEP while 80211i was prepared WPA implemented a subset of 80211i 3980211i It supersedes the previous security specification Wired Equivalent Privacy WEPWiFi Protected Access WPA had previously been introduced by the WiFi Alliance as an intermediate solution to WEP insecurities 80211i makes use of the Advanced Encryption Standard AES block cipher WEPWired Equivalent Privacy Security Goals Confidentiality To prevent casual eavesdropping Access control To protect access to a wireless network infrastructure Data integrity To prevent tampering with transmitted messages Protocol 011 a secret key shared between the communicatirt the ody of transmitted frame of data 11 of the frame proceeds as follows umming Plaintext gt Message I CRC l l Keystream RC4vk l 39l39ransmjtted Data awed app 39c encryption using RC4 afted integrity protection using CRC RIna dequate authentication address protection ay protection date mechanism WPAWireless Protocol Access WPA still uses the WEP algorithm but adds a stronger integrity checking algorithm and better key management as in 8021X A subset of the current version of 80211i which includes Temporal Key Integrity Protocol TKIP and 8021X mechanisms The combination of these two mechanisms provides dynamic key encryption and mutual authentication something much needed in WLANs 39With WPA an environment having many different types of 80211 radio NICs such as public hotspots can benefit from enhanced forms of encryption a shell placed around the WEP RC4 algorithm to weaknesses replay attacks forgery attacks key quot Weak key attacks 1 integrity checking hzation vector sequencing rules 39 quot per packet key TKIP TKIP is a quotwrapperquot that goes around the existing WEP encryption This solves the first problem of WEP a tooshort key length TKIP changes the key used for each packet The key is created by mixing together a combination of things including a base key The most important piece that is mixed into the TKIP key is the base key Each packet transmitted using TKIP has a unique 48bit serial number that is incremented every time a new packet is transmitted and used both as the Imtialization Vector and part of the key This solves another problem of WEP called quotcollision attacksquot which can occur when the same key is used for two different packets m 39 i Wrmm WWW WPA Authentication EAPExtensibe Authentication Protocol Authentication Server accepts user s credentials Authentication Server uses 8021X framework and EAP to generate unique master key 8021X distributes the key to the AP and the client TKIP sets up a key hierarchy and management system using the master key In other words unique data encryption keys to encrypt every data packet are generated from the master key PSKPreShared keys Users are authenticated to the Access Point AP with a passphrase which is 863 ASCII characters PSK mode employs also PBKDFZ key derivation function which uses a repeated process of cryptographic hash to the passphrase As a result stronger and more secure password is generated o rk access control 802 1X EAP Radius 111th ction taand header integrity Comparison of WEP amp WPA Encryption Cracked Key length 40104 bits Key type Static keys Key distribution Manual Authentication WEP key Key management No Replay protection No Fixes WEP flaws 128 bits Dynamic keys AutomaticTKP 8021XEAP Yes Yes 80211i 39The 80211i standard was officially ratified by the IEEE in 2004 80211i is a standard for WLANs that provides improved encryption for networks that use the popular 80211a 80211bwhich includes WiFi and 80211g standards The 80211i standard requires new encryption key protocols known as Temporal Key Integrity Protocol TKIP and Advanced Encryption Standard AES Features of 80211i are Key caching facilitates fast reconnection to the server for users who have temporarily gone of ine Preauthentication allows fast roaming and is ideal for use with advanced applications such as Voice over Internet Protocol VoIP 8021 1i Protocol 3980211i has been designed to provide enhanced MAC security in WLAN system The 80211i standard requires new encryption key protocols known as Temporal Key Integrity Protocol TKIP and Advanced Encryption Standard AES 3980211i introduced RSNrobust secure Network protocol for establishing secure communications It introduced CCMP encryption protocol which is based on AES encryption algorithm The biggest difference between RSNCCMP and WPATKIP is at the lower layers where data is encrypted and decrypted TKIP uses 4 temporal keys whereas AES uses only 3Key management is same for both protocols 802l li Components 1Temp0ral Key Integrity Protocol TKIP A dataconfidentiality protocol TKIP uses a message integrity code called Michael which enables devices to authenticate that the packets are coming from the claimed source 2 CounterModeCBCMAC Protocol CCMP A dataconfidentiality protocol that handles packet authentication as well as encryption For con dentiality CCMP uses AES in counter mode For authentication and integrity CCMP uses Cipher Block Chaining Message Authentication Code CBCMAC 31EEE 8021x Offers an effective framework for authenticating and controlling user traffic to a protected network as well as dynamically varying encryption keys 8021X ties a protocol called EAP Extensible Authentication Protocol to both the wired and wireless LAN media and supports multiple authentication methods 4 EAP encapsulation over LANs EAPOL7 Key protocol in IEEE 8021x for key exchange Two main EAPOLkey exchanges the 4way handshake and the group key handshake 80211i advantages amp disadvantages Advantages 39802 1 11 provides stronger encryption that WEP and WPA 39802 1 li encrypts whole data frame with AES whereas WEPWPA encrypt only the data payload using RC4 cipher Disadvantage 39802 1 li requires its own coprocessor which means that older existing hardware can t be just upgraded via software as with the transition to WPA DH39IONAL SECURITY ROBUST SECURITY 8021 1i f l I39ROVED SECURITY WPA POOR SECURITY WEP Wmi a iance 1997 2002 2003 2003 I 2004K years Conclusron susceptible to attack using fairly modest 39 Provides an interim solution to the WEP problem 39 upport for legacy wireless infrastructure 80211i standard provides robust security needed en ronrnents in the future 39


Buy Material

Are you sure you want to buy this material for

25 Karma

Buy Material

BOOM! Enjoy Your Free Notes!

We've added these Notes to your profile, click here to view them now.


You're already Subscribed!

Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'

Why people love StudySoup

Bentley McCaw University of Florida

"I was shooting for a perfect 4.0 GPA this semester. Having StudySoup as a study aid was critical to helping me achieve my goal...and I nailed it!"

Jennifer McGill UCSF Med School

"Selling my MCAT study guides and notes has been a great source of side revenue while I'm in school. Some months I'm making over $500! Plus, it makes me happy knowing that I'm helping future med students with their MCAT."

Jim McGreen Ohio University

"Knowing I can count on the Elite Notetaker in my class allows me to focus on what the professor is saying instead of just scribbling notes the whole time and falling behind."

Parker Thompson 500 Startups

"It's a great way for students to improve their educational experience and it seemed like a product that everybody wants, so all the people participating are winning."

Become an Elite Notetaker and start selling your notes online!

Refund Policy


All subscriptions to StudySoup are paid in full at the time of subscribing. To change your credit card information or to cancel your subscription, go to "Edit Settings". All credit card information will be available there. If you should decide to cancel your subscription, it will continue to be valid until the next payment period, as all payments for the current period were made in advance. For special circumstances, please email


StudySoup has more than 1 million course-specific study resources to help students study smarter. If you’re having trouble finding what you’re looking for, our customer support team can help you find what you need! Feel free to contact them here:

Recurring Subscriptions: If you have canceled your recurring subscription on the day of renewal and have not downloaded any documents, you may request a refund by submitting an email to

Satisfaction Guarantee: If you’re not satisfied with your subscription, you can contact us for further help. Contact must be made within 3 business days of your subscription purchase and your refund request will be subject for review.

Please Note: Refunds can never be provided more than 30 days after the initial purchase date regardless of your activity on the site.