Leo Lam Signals and Systems EE253 Leo Lam Leo Lam Todays menu Introductions Class logistics and expectations Help available Course material starts! Leo Lam Introduction Who is this bozo? Anonymous message welcome Office: 253D Performance guarantee 12-hourresponse Reasonable Five questions! Leo Lam Introduction TA: Chris Mandic Office hours: TBD MATLAB wiz Leo Lam Introduction You! Goal Introduction to the language of signals Manipulating the language (the system) Using MATLAB to play with it Preparation for DSP etc. System level thinking Engineering sense Communicating with each other technically Discipline in practicing engineering Leo Lam Logistics Four lectures One lab per week Lab begins this week (need EE account) Grading 60% consistent work 40% exams (1 week-5 midterm/1 Final) Fair, consistent, not mean Textbook: Not required, but recommended Website: wp.ee.washington.edu/ee235sum2011/ Pre-req: Math 136,307,Amath 351, PHY 122 or CSE 142 etc. Leo Lam Expectations Active, curious, question Work together No cheating! Lab (six labs) Read the manual Communicate clearly Collaborate Leo Lam Help? GoPost Your learning social media Me and TA (office hours) Each other (and meet new friends!) HKN help for 215, 233, 235 (may not be available in the summer) Leo Lam Questions? Before the launch Examples of a signal? Electrical parameter over time Radio over time and space Sound/Pressure over time Medical parameters over time Images Video Stock prices (discrete time) People in a room daily (discrete variable/time) Leo Lam Definition: Signal A signal is a set of information or data that can be modeled as a function of one or more independent variables. Leo Lam Theres a theme here Continuous time Continuous variable e.g. talking to you Continuous time Discrete Variable e.g. people in the room Discrete time Continuous variable e.g. daily temperature Discrete time Discrete variable e.g. data recorded on CD Leo Lam Taking a signal apart Leo Lam a0a0 T t (seconds) A+a 0 A sound signal Offset (atmospheric pressure) Frequency Amplitude Frequency Leo Lam t (seconds)f (Hz) = time-domainfrequency-domain t to f Leo Lam t (seconds) F (Hz) Combining signals Leo Lam Summary: Signals Signals carry information Signals represented by functions over time or space Signals can be represented in frequency domain Signals can be summed in both time and frequency Leo Lam Systems A system describes a relationship between input and output Examples? Leo Lam v(t)y(t)g(t) Definition: System A system modifies signals or extracts information. It can be considered a transformation that operates on a signal. Leo Lam Motivation: Complex systems Leo Lam Filters All kinds, and everywhere Leo Lam Surprising high pass Leo Lam Today What is a signal What is a system Some examples Leo Lam