ITGD3101Modern Telecommunications Lecture-5- Pulse Code Modulation week 5- q-2/ 2008 Dr. Anwar Mousa University of Palestine Faculty of Information Technology

UP-Copyrights reserved2 Contents Sampling theorem Quantization Pulse Code Modulation

UP-Copyrights reserved3 Aperiodic signal representation by Fourier Transform

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6 Today, we are going to talk about: The first important step in any DCS: Transforming the information source to a form compatible with a digital system

UP-Copyrights reserved7 Encode Transmit Pulse modulate SampleQuantize Demodulate/ Detect Channel Receive Low-pass filter Decode Pulse waveforms Bit stream Format Digital info. Textual info. Analog info. Textual info. Analog info. Digital info. source sink Formatting and transmission of baseband signal

UP-Copyrights reserved8 Format analog signals To transform an analog waveform into a form that is compatible with a digital communication, the following steps are taken: 1.Sampling 2.Quantization and encoding 3.Baseband transmission

UP-Copyrights reserved9 Sampling theorem

UP-Copyrights reserved10 Sampling theorem

UP-Copyrights reserved11 Aliasing effect LP filter Nyquist rate aliasing

UP-Copyrights reserved12 Sampling theorem

UP-Copyrights reserved13 Sampling theorem Sampling theorem: A bandlimited signal with no spectral components beyond, can be uniquely determined by values sampled at uniform intervals of The sampling rate, is called Nyquist rate. Sampling process Analog signal Pulse amplitude modulated (PAM) signal

UP-Copyrights reserved14 Sampling theorem

UP-Copyrights reserved15 Sampling theorem

UP-Copyrights reserved16 Pulse Code Modulation (PCM).

UP-Copyrights reserved17 Pulse Code Modulation (PCM).

UP-Copyrights reserved18 Pulse Code Modulation (PCM).

UP-Copyrights reserved19 Quantization example t Ts: sampling time x(nTs): sampled values xq(nTs): quantized values boundaries Quant. levels PCM codeword PCM sequence amplitude x(t)

UP-Copyrights reserved20 Pulse Code Modulation (PCM).

UP-Copyrights reserved21 Pulse Code Modulation (PCM).

UP-Copyrights reserved22 Pulse Code Modulation (PCM).

UP-Copyrights reserved23 Advantages of Digital Communications

UP-Copyrights reserved24 Advantages of Digital Communications

UP-Copyrights reserved25 Advantages of Digital Communications

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UP-Copyrights reserved31 Summary We have studies the following topics: Sampling theorem Quantization Pulse Code Modulation

UP-Copyrights reserved32 Contents Principles of Digital Data Transmission Line coding ON-OFF Polar BIPOLAR HDB-3

UP-Copyrights reserved33 Today, we are going to talk about: Principles of Digital Data Transmission

UP-Copyrights reserved34 Principles of Digital Data Transmission

UP-Copyrights reserved35 Line Coder

UP-Copyrights reserved36 Line Coder

UP-Copyrights reserved37 Line Coder

UP-Copyrights reserved38 Line Coding

UP-Copyrights reserved39 Line Coding