digital communications modulation and coding course

... bandwidth constraint  Nyquist bandwidth constraint:  The theoretical minimum required system bandwidth to detect Rs [symbols/s] without ISI is Rs/2 [Hz].  Equivalently, a system with bandwidth ... filter Equalizing filter Threshold comparison For bandpass signals Compensation for channel induced ISI Baseband pulse (possibly distored) Sample (test statistic) Baseband pulse Received waveform Step 1 – ... [symbols/s] without ISI.  Bandwidth efficiency, R/W [bits/s/Hz] :  An important measure in DCs representing data throughput per hertz of bandwidth.  Showing how efficiently the bandwidth resources...

Ngày tải lên: 18/10/2013, 06:15

... features of digital communication systems  Some basic concepts and definitions such as as signal classification, spectral density, random process, linear systems and signal bandwidth. Lecture ... stream Format Format Digital info. Textual info. Analog info. Textual info. Analog info. Digital info. source sink Formatting and transmission of baseband signal Lecture 2 21 M-ary pulse modulation  M-ary ... with a digital system Lecture 2 20 Spectra of PCM waveforms Lecture 2 10 Encoding (PCM)  A uniform linear quantizer is called Pulse Code Modulation (PCM).  Pulse code modulation (PCM): Encoding...

Ngày tải lên: 23/03/2014, 10:21

... PAM T t )( 1 t ψ T 1 0 Digital Communications I: Modulation and Coding Course Term 3 - 2008 Catharina Logothetis Lecture 5 Lecture 5 2 Last time we talked about:  Receiver structure  Impact of AWGN and ISI ... noise vector are i.i.d Gaussian random variables with zero-mean and variance . The noise vector pdf is  The elements of observed vector are independent Gaussian random variables. Its pdf is ), ... to maximize SNR  Matched filter and correlator receiver  Signal space used for detection  Orthogonal N-dimensional space  Signal to waveform transformation and vice versa Lecture 5 7 Detection...

Ngày tải lên: 23/03/2014, 10:21

... and evaluation of the code.  Block codes are based on algebraic/combinatorial techniques.  Convolutional codes are based on construction techniques. Digital Communications I: Modulation and ... encoder. Lecture 10 10 Effective code rate  Initialize the memory before encoding the first bit (all- zero)  Clear out the memory after encoding the last bit (all- zero)  Hence, a tail of zero-bits is ... of data bits and k=1 is assumed: data Encoder codewordtail ceff R KLn L R < −+ = )1( Lecture 10 4 Convolutional codes  Convolutional codes offer an approach to error control coding substantially...

Ngày tải lên: 30/03/2014, 10:20

Ngày tải lên: 30/03/2014, 10:20

... ,zzZ ZZZZ = =Z Channel Lecture 10 2 Last time, we talked about:  Channel coding  Linear block codes  The error detection and correction capability  Encoding and decoding  Hamming codes  Cyclic codes Lecture 10 ... design and evaluation of the code.  Block codes are based on algebraic/combinatorial techniques.  Convolutional codes are based on construction techniques. Digital Communications I: Modulation and ... specified by three parameters or where  is the coding rate, determining the number of data bits per coded bit.  In practice, usually k=1 is chosen and we assume that from now on.  K is the constraint...

Ngày tải lên: 25/10/2013, 06:15

... error correction coding?  Error performance vs. bandwidth  Power vs. bandwidth  Data rate vs. bandwidth  Capacity vs. bandwidth (dB) / 0 NE b B P A F B D C E Uncoded Coded Coding gain: For ... coset kknknkn k k 22 2 22 2 2222 2 21 UeUee UeUee UUU ⊕⊕ ⊕⊕ −−− L MOLM L L zero codeword coset coset leaders kn i − = 2, ,3,2 n V i e th:i Digital Communications I: Modulation and Coding Course Period 3 - 2007 Catharina Logothetis Lecture 9 Lecture 9 36 Cyclic ... detection and correction codes Lecture 9 28 Linear block codes – cont’d  Standard array  For row , find a vector in of minimum weight which is not already listed in the array.  Call this pattern and...

Ngày tải lên: 25/10/2013, 06:15

... information provides the decoder with a measure of confidence for the decision. Digital Communications I: Modulation and Coding Course Period 3 - 2007 Catharina Logothetis Lecture 12 ... each state, and keeps only the path with the largest metric, called the survivor, together with its metric. Lecture 12 6 Soft and hard decision decoding …  ML soft-decisions decoding rule:  Choose ... code uses two levels on coding, an inner code and an outer code (higher rate).  Popular concatenated codes: Convolutional codes with Viterbi decoding as the inner code and Reed-Solomon codes...

Ngày tải lên: 29/10/2013, 13:15

... levels.  Decoding based on soft-bits, is called the “soft-decision decoding”.  On AWGN channels, 2 dB and on fading channels 6 dB gain are obtained by using soft-decoding over hard-decoding. Lecture ... state 101 010 11 011 100 10 001 110 01 111 000 00 0 S 1 S 2 S 3 S 0 S 2 S 0 S 2 S 1 S 3 S 3 S 1 S 0 S 1 S 2 S 3 S 1/11 1/00 1/01 1/10 0/11 0/00 0/01 0/10 Input Output (Branch word) Modulation, Demodulation and Coding Course Period 3 - 2007 Catharina Logothetis Lecture 11 ... level) which are called “hard- bits”.  Decoding based on hard-bits is called the “hard-decision decoding”. Lecture 11 23 Example of Hard decision Viterbi decoding-cont’d  i=3 0 2 0 1 2 1 0 1 1 0 1 2 2 1 0 2 1 1 1 6 t 1 t 2 t 3 t 4 t 5 t 1 0 2...

Ngày tải lên: 29/10/2013, 13:15

... Input Output Linear system Digital Communication I: Modulation and Coding Course Period 3 - 2007 Catharina Logothetis Lecture 1 Lecture 1 12 Digital versus analog  Advantages of digital communications:  Regenerator ... issues in designing a digital communication system (DCS):  Utilized techniques  Formatting and source coding  Modulation (Baseband and bandpass signaling)  Channel coding  Equalization  Synchronization  ... ergodic in mean and autocorrelation, if and , respectively. Lecture 1 7 Practical information  Course material  Course text book:  Digital communications: Fundamentals and Applications”...

Ngày tải lên: 08/11/2013, 18:15

... variance: 2 Sat 2 Lin 222 )()(})]({[ σσσ +==−= ∫ ∞ ∞− dxxpxexqx q E ll L l l qxp q )( 12 2 12/ 0 2 2 Lin ∑ − = = σ Uniform q. 12 2 2 Lin q = σ Digital Communications I: Modulation and Coding Course Period 3 – 200/ Catharina Logothetis Lecture 2 Lecture 2 18 PCM waveforms  PCM ... about:  Important features of digital communication systems  Some basic concepts and definitions as signal classification, spectral density, random process, linear systems and signal bandwidth. Lecture ... NRZ Lecture 2 21 M-ary pulse modulation  M-ary pulse modulations category:  M-ary pulse-amplitude modulation (PAM)  M-ary pulse-position modulation (PPM)  M-ary pulse-duration modulation (PDM)  M-ary...

Ngày tải lên: 08/11/2013, 18:15

... with a digital system  Sampling  Aliasing  Quantization  Uniform and non-uniform  Baseband modulation  Binary pulse modulation  M-ary pulse modulation  M-PAM (M-ay Pulse amplitude modulation) Lecture ... symbol Mi ,,1 K = M-ary modulation Lecture 3 13 Baseband and bandpass  Bandpass model of detection process is equivalent to baseband model because:  The received bandpass waveform is first ... goals.  First, we focus on designing a receiver which maximizes the SNR. Digital Communication I: Modulation and Coding Course Period 3 - 2007 Catharina Logothetis Lecture 3 Lecture 3 20 Implementation...

Ngày tải lên: 27/01/2014, 08:20

... filters )()( tTstrz i i −∗= ∗ Mi , ,1 = ), ,,())(), ,(),(( 2121 MM zzzTzTzTz = =z Digital Communications I: Modulation and Coding Course Period 3 - 2007 Catharina Logothetis Lecture 4 Lecture 4 11 Signal ... A 0 1 s 2 s T A T A− 0 0 Tt )( 1 t ψ T 1 0 0)()()()( )()()(),( /)(/)()( )( 122 0 1212 1111 0 2 2 11 =−−= −=>=< == == ∫ ∫ tAtstd Adtttstts AtsEtst AdttsE T T ψ ψψ ψ 1 2 Lecture 4 3 Receiver job  Demodulation and sampling:  Waveform recovery and preparing the received signal for detection:  Improving the signal ... filter Equalizing filter Threshold comparison For bandpass signals Compensation for channel induced ISI Baseband pulse (possibly distored) Sample (test statistic) Baseband pulse Received waveform Step 1 –...

Ngày tải lên: 27/01/2014, 08:20

... PAM T t )( 1 t ψ T 1 0 Digital Communications I: Modulation and Coding Course Period 3 - 2007 Catharina Logothetis Lecture 5 Lecture 5 20 Eb/No figure of merit in digital communications  SNR ... noise vector are i.i.d Gaussian random variables with zero-mean and variance . The noise vector pdf is  The elements of observed vector are independent Gaussian random variables. Its pdf is ), ... liesPr()( )(1)( icie mPmP − = i m i s z i Z sent) and ˆ Pr()( iiie mmmmP ≠ = Lecture 5 16 Union bound  Let denote that the observation vector is closer to the symbol vector than , when is transmitted.  depends only on and .  Applying...

Ngày tải lên: 27/01/2014, 08:20

... Polytechnic Institute and State University Blacksburg, Virginia Multi-Carrier Digital Communications: Theory and Applications of OFDM Ahmad R. S. Bahai and Burton R. Saltzberg Principles of Digital Transmission: ... publisher. Multi-Carrier Digital Communications Theory and Applications of OFDM Introduction to Digital Communications 11 (illustrated in Figure 1.6). Unlike the non-bandlimited OFDM, each carrier must ... the modulation and demodulation processes [7]. Fortunately, this occurred at the same time digital signal processing techniques were being introduced into the design of Multi-Carrier Digital Communications Theory...

Ngày tải lên: 02/03/2013, 16:58

Ngày tải lên: 21/06/2014, 02:20

Ngày tải lên: 22/06/2014, 06:20

Ngày tải lên: 22/06/2014, 19:20