PCM - Coding and Information Theory - Old Exam Paper, Exams of Information Technology

Download PCM - Coding and Information Theory - Old Exam Paper and more Exams Information Technology in PDF only on Docsity! Page 1 of 5 CORK INSTITUTE OF TECHNOLOGY INSTITIÚID TEICNEOLAÍOCHTA CHORCAÍ Semester 1 Examinations 2011/12 Module Title: Coding and Information Theory Module Code: CTEC8001 School: Mathematics and Computing Programme Title: Bachelor of Science in Software Development and Computer Networking–Y3 Programme Code: KDNET_8_Y3 External Examiner(s): Ms Erica Gill Internal Examiner(s): Dr. Oliver Gough Instructions: Answer four questions Duration: 2 Hours Sitting: Winter 2011 Requirements for this examination: Note to Candidates: Please check the Programme Title and the Module Title to ensure that you have received the correct examination paper. If in doubt please contact an Invigilator. Page 2 of 5 Q1. (a) A PC generates data at a rate of 115 kbps. The data or bit stream is then encoded to form symbols with M =128 prior to transmission. What is the baud rate on the transmission line and determine the minimum bandwidth required for the transmission line. (8 marks) (b) Explain the operation of a Pulse-Code -Modulation (PCM) system. Discuss the advantages and disadvantages of such a system. (7 marks) (c) An audio source is band-limited to 10 kHz is encoded using linear 16 bit PCM and is transmitted over a data network. Determine the sampling rate, the bit rate and the required bandwidth. (5 marks) (d) An RF channel has a bandwidth of 6 MHz. Determine the minimum SNR required to support a data rate of 27 Mb/s. (Note log2X=3.32*log10X) (5 marks) Q2. (a) Write a short note on the use of frequency hop spread spectrum in Bluetooth communications systems. (8 marks) (b) Discuss the variety of modulation schemes in use in 802.11 WLANs (8 marks) (c) A Direct-Sequence Spread Spectrum (DS-SS) CDMA system requires a processing gain of 42 dB, and employs a 14-stage shift register m-sequence pseudo-random generator to transmit a data message at 14400 bps on a 1200 MHz carrier. Determine the following parameters:- (i) Required chip rate of the code generator (3 marks) (ii) Spectral line spacing in the signal (3 marks) (ii) First-lobe bandwidth and sketch the resulting frequency spectrum. (3 marks)