Chapter 3 Pulse Modulation ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

Haykin/Communication Systems, 4th Ed Chapter Outline Sampling: is basic to all forms of pulse modulation. Pulse-amplitude modulation (PAM): is the simplest form of modulation. Quantization: when combined with sampling, permits to digitize analog signals. Pulse-code modulation (PCM): is the standard method used to transmit analog signals by digital means. Time-division multiplexing: provides for the time sharing by a common channel. ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

Chapter Outline (Continued) Digital multiplexers: combines many slow bit streams into a single faster stream. Other forms of PCM: delta modulation (DM) and differential PCM (DPCM). Linear prediction: is a basic form of encoding analog message signals at low bit rates as in DPCM. Adaptive forms of DPCM and DM. The MPEG-1/audio coding standard: is a transpa-rent, perceptually loss-less compression system for audio signals. ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

Haykin/Communication Systems, 4th Ed Sampling Process ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

Sampling Process (Continued) ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

Sampling Process (Continued) ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

Haykin/Communication Systems, 4th Ed Figure 3.1 The sampling process. (a) Analog signal. (b) Instantaneously sampled version of the analog signal. ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

Haykin/Communication Systems, 4th Ed Figure 3.2 (a) Spectrum of a strictly band-limited signal g(t). (b) Spectrum of the sampled version of g(t) for a sampling period Ts = 1/2 W. ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

Signal Reconstruction ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

Signal Reconstruction (Cont’d) ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

Haykin/Communication Systems, 4th Ed Sampling Theorem ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

Haykin/Communication Systems, 4th Ed Aliasing Effect ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

Haykin/Communication Systems, 4th Ed Figure 3.3 (a) Spectrum of a signal. (b) Spectrum of an undersampled version of the signal exhibiting the aliasing phenomenon. ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

Haykin/Communication Systems, 4th Ed Figure 3.4 (a) Anti-alias filtered spectrum of an information-bearing signal. (b) Spectrum of instantaneously sampled version of the signal, assuming the use of a sampling rate greater than the Nyquist rate. (c) Magnitude response of reconstruction filter. ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

Haykin/Communication Systems, 4th Ed Example ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

Haykin/Communication Systems, 4th Ed Example (Continued) ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

Pulse-Amplitude Modulation ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

Figure 3.5 Flat-top samples, representing an analog signal. ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

Haykin/Communication Systems, 4th Ed PAM (Continued) ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

Haykin/Communication Systems, 4th Ed PAM (Continued) ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

Haykin/Communication Systems, 4th Ed Figure 3.6 (a) Rectangular pulse h(t). (b) Spectrum H(f), made up of the magnitude |H(f)|, and phase arg[H(f)]. ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

Haykin/Communication Systems, 4th Ed Figure 3.7 System for recovering message signal m(t) from PAM signal s(t). ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

Other Forms of Pulse Modulation ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

Haykin/Communication Systems, 4th Ed Figure 3.8 Illustrating two different forms of pulse-time modulation for the case of a sinusoidal modulating wave. (a) Modulating wave. (b) Pulse carrier. (c) PDM wave. (d) PPM wave. ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

Bandwidth-Noise Trade-off ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

Haykin/Communication Systems, 4th Ed Quantization Process ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

Quantization Process (Cont’d) ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

Quantization Process (Cont’d) ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

Figure 3.9 Description of a memoryless quantizer. ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

Figure 3.10 Two types of quantization: (a) midtread and (b) midrise. ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

Haykin/Communication Systems, 4th Ed Figure 3.11 Illustration of the quantization process. (Adapted from Bennett, 1948, with permission of AT&T.) ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

Haykin/Communication Systems, 4th Ed Figure 3.12 Illustrating the partitioning of the dynamic range A  m  A of a message signal m(t) into a set of L cells. ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

Haykin/Communication Systems, 4th Ed Example ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

Haykin/Communication Systems, 4th Ed Example (Continued) ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

Pulse-Code Modulation ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

Pulse-Code Modulation (Cont’d) ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

Figure 3.13 The basic elements of a PCM system. ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

Figure 3.14 Compression laws. (a) m -law. (b) A-law. ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

Pulse-Code Modulation (Cont’d) ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

Haykin/Communication Systems, 4th Ed Figure 3.15 Line codes for the electrical representations of binary data. (a) Unipolar NRZ signaling. (b) Polar NRZ signaling. (c) Unipolar RZ signaling. (d) Bipolar RZ signaling. (e) Split-phase or Manchester code. ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

Haykin/Communication Systems, 4th Ed Figure 3.16a Power spectra of line codes: (a) Unipolar NRZ signal. The frequency is normalized with respect to the bit rate 1/Tb, and the average power is normalized to unity. ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

Haykin/Communication Systems, 4th Ed Figure 3.16b Power spectra of line codes: (b) Polar NRZ signal. The frequency is normalized with respect to the bit rate 1/Tb, and the average power is normalized to unity. ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

Haykin/Communication Systems, 4th Ed Figure 3.16c Power spectra of line codes: (c) Unipolar RZ signal. The frequency is normalized with respect to the bit rate 1/Tb, and the average power is normalized to unity. ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

Haykin/Communication Systems, 4th Ed Figure 3.16d Power spectra of line codes: (d) Bipolar RZ signal. The frequency is normalized with respect to the bit rate 1/Tb, and the average power is normalized to unity. ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

Haykin/Communication Systems, 4th Ed Figure 3.16e Power spectra of line codes: (e) Manchester-encoded signal. The frequency is normalized with respect to the bit rate 1/Tb, and the average power is normalized to unity. ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

Pulse-Code Modulation (Cont’d) ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

Haykin/Communication Systems, 4th Ed Noise in PCM Systems ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

Haykin/Communication Systems, 4th Ed Figure 3.17 (a) Original binary data. (b) Differentially encoded data, assuming reference bit 1. (c) Waveform of differentially encoded data using unipolar NRZ signaling. ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

Figure 3.18 Block diagram of regenerative repeater. ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

Time-Division Multiplexing ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

Figure 3.19 Block diagram of TDM system. ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

Haykin/Communication Systems, 4th Ed Digital Multiplexers ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

Figure 3.20 Conceptual diagram of multiplexing-demultiplexing. ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

Digital Multiplexers (Continued) ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

Digital Multiplexers (Continued) ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

Figure 3.21 Signal format of AT&T M12 multiplexer. ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

Virtues and Limitations of PCM ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

Haykin/Communication Systems, 4th Ed Delta Modulation (DM) ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

Delta Modulation (Cont’d) ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

Delta Modulation (Cont’d) ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

Figure 3.22 Illustration of delta modulation. ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

Figure 3.23 DM system. (a) Transmitter. (b) Receiver. ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

Haykin/Communication Systems, 4th Ed Figure 3.24 Illustration of the two different forms of quantization error in delta modulation. ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

Delta-Sigma Modulation ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

Figure 3.25 Two equivalent versions of delta-sigma modulation system. ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

Haykin/Communication Systems, 4th Ed Linear Prediction ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

Linear Prediction (Continued) ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

Linear Prediction (Continued) ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

Figure 3.26 Block diagram of a linear prediction filter of order p. ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

Haykin/Communication Systems, 4th Ed Figure 3.27 Block diagram illustrating the linear adaptive prediction process. ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

Differential PCM (DPCM) ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

Differential PCM (Continued) ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

Figure 3.28 DPCM system. (a) Transmitter. (b) Receiver. ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

Haykin/Communication Systems, 4th Ed Adaptive DPCM ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

Adaptive DPCM (Continued) ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

Figure 3.29 Adaptive quantization with backward estimation (AQB). ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

Figure 3.30 Adaptive prediction with backward estimation (APB). ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

Computer Experiment: Adaptive delta Modulation ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

Haykin/Communication Systems, 4th Ed Figure 3.31 Adaptive delta modulation system: (a) Transmitter. (b) Receiver. ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

Haykin/Communication Systems, 4th Ed Figure 3.32 Waveforms resulting from the computer experiment on delta modulation: (a) Linear delta modulation. (b) Adaptive delta modulation. ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

MPEG/Audio Coding System ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

MPEG/Audio Coding System (Continued) ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

Haykin/Communication Systems, 4th Ed Figure 3.33 Illustrating the definitions of masking threshold and related parameters. The high-level signal (masker) lies inside the darker-shaded critical band, hence the masking is more effective in this band than in the neighboring band shown in lighter shading. (Adapted from Noll (1998) with permission of the CRC Press.) ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

Figure 3.34 MPEG/Audio coding system. (a) Transmitter. (b) Receiver. ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

Haykin/Communication Systems, 4th Ed Figure P3.5 ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

Haykin/Communication Systems, 4th Ed Figure P3.22 ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018

Haykin/Communication Systems, 4th Ed Figure P3.37 ©2000, John Wiley & Sons, Inc. Haykin/Communication Systems, 4th Ed 9/16/2018