PPT-Chapter 4: Second generation Systems-Digital Modulation

Audiovideo signals are analog in nature Analog signals can take infinite number of values Hence more difficult to detect at receiver after noise corruption PCM converts analog signals to digital pulses. We have no digital cable boxes that will work on digital cable tv No digital cable box is available Digital cable descrambler and digital cable box will be available someday At this time no digital cable tv box is available Look for digital cable de Husheng Li. The University of Tennessee. Chopper Sampling . We introduce a switching function such that . x_s. (t)=x(t)s(t), where. Nyquist. Criterion. The sampling rate should be at least twice the bandwidth of the signal, in order to fully reconstruct the signal.. Section 6.6. DSB/SC-AM . Modulation (Review). Frequency Shift . Property (Review). Frequency Spectrum of DSB/SC-AM . Signal (Review). Carrier Signal for Amplitude Modulation. Pulse Amplitude Modulation. nalhareqi-2013. 1. Standard Amplitude Modulation (AM). nalhareqi-2013. 2. In the DSP-SC demodulation, a receiver must generate a local carrier in frequency and phase synchronism with the carrier used for modulation.. Dr. Mohamed Bingabr. Chapter 1. Introduction. ENGR 4323/5323. Digital and Analog Communication. Why Communication. Communication advances society’s development.. Before. . modern time . verbal messages were carried by runners, carrier . Exchange of information from point A to point B. 100001101010001011101. 100001101010001011101. Transmit. Receive. Wireless Communication. Exchange of information from point A to point B. 100001101010001011101. Amplitude Modulation (AM). Time domain equation. y. AM. (t. ) = . Information or message x carrier. . = . m(t) . x A cos(w. c. t. ). . Frequency domain equation. Double . sideband . Analogue to Digital Conversion. Quantizing. Encoding. Pulse Code Modulation. DEFINITION: . Pulse code modulation (PCM) is essentially analog-to-digital conversion of a special type where the . information . Digital. . Modulation. Announcements:. Slides from . Cioffi. guest lecture posted. . HW 1 solutions posted, graded HWs available soon.. Review . of Lecture 8 (last Wednesday). AM Radio Modulation and Demodulation. Tenenbaum, . Wetherall. (uploaded on Canvas). Communication. Exchange of information from point A to point B. 100001101010001011101. 100001101010001011101. Transmit. Receive. Wireless Communication. Binary modulation schemes . ASK. , FSK, . PSK. n. = . 1, . M = 2 (Only Two . output conditions are . possible). Baud . is equal to . the bit . rate. M-. ary. Modulation Techniques. QPSK, 8-PSK, 18-PSK, QAM, 16-QAM. Example: ASK, FSK, PSK, QAM. Binary digital modulation. Multilevel digital modulation. Amplitude Shift Keying. Binary-ASK --- BASK. Or On-Off Keying OOK. Uses two amplitude levels for the modulated carrier . 1. http://www.gaussianwaves.com/2012/05/performance-comparison-of-digital-modulation-techniques/. Note: M=2^m. Prof. Brian L. Evans. Dept. of Electrical and Computer Engineering. The University of Texas at Austin. 15 - . 2. Introduction. Digital Pulse Amplitude Modulation (PAM). Modulates digital information (symbols) onto amplitude of pulse.