tailieunhanh - Lecture Digital communication systems - Lecture 15

The main contents of this chapter include all of the following: Defining advertising, a brief history of advertising, advertising in the digital age, organization of the consumer advertising industry, producing advertising, economics, business-to-business advertising. | D 00 00 oo oo 00 00 00 00 00 INTRODUCTION TO1 EECS II DIGITAL COMMUNICATION SUSTEMS Fall 2012 Lecture 15 Modulation - to match the transmitted signal to the physical medium Demodulation Fall 2012 Lecture 15 Slide 1 Single Link Communication Model ________________ End-host Original source computers I I Digitize if needed Source binary digits message bits Source coding Bit stream Receiving app user Render display etc. Source decoding Bit stream Channel Coding bit error correction Bits Mapper Xmit samples Signals Voltages over physical link Recv samples Bits Demapper Channel Decoding reducing or removing bit errors Fall 2012 Lecture 15 Slide 3 DT Fourier Transform DTFT for Spectral Representation of General x n 4n -L f X Q eiQ Q where 2n 2n X Q 2 4 m e JQm m This Fourier representation expresses x n as a weighted combination of e7 n for all Q in - 7Ĩ . X Qo dQ is the spectral content of x n in the frequency interval Qo Qo dQ Fall 2012 Lecture 15 Slide