Digital transmission over bandlimited channels is studied. The concept of intersymbol interference (ISI) is described, and the Nyquist criterion for no ISI is derived. The raised cosine pulse, a widely used example of a practical communication pulse resulting in no ISI, is introduced. Both ideal and non-ideal bandlimited channels are considered. In addition, the power spectral density of digitally modulated signals is derived, and the spectral efficiencies of different digital modulation schemes are computed.

The transmission of bandpass signals and the corresponding channel effects are introduced. Basic single-carrier bandpass modulation schemes – namely, bandpass pulse amplitude modulation, phase-shift keying, and quadrature amplitude modulation – are studied. Lowpass equivalents of bandpass signals are introduced, and the in-phase and quadrature components of a bandpass signal are described. It is shown that bandpass signals and systems can be studied through their lowpass equivalents. The π/4-QPSK and offset QPSK are presented as two practically motivated variations of quadrature phase-shift keying. Coherent, differentially coherent, and non-coherent receivers are described. Differential phase-shift keying is studied in some depth. Finally, carrier phase-synchronization methods, including the use of phase-locked loops, are described.

Deterministic signals and linear time-invariant systems are studied. The Fourier transform is introduced, and its properties are reviewed. The concepts of probability and random variables are developed. Conditional probability is defined, and the total probability theorem and Bayes’ rule are given. Random variables are studied through their cumulative distribution functions and probability density functions, and statistical averages, including the mean and variance, are defined. These concepts are extended to random vectors. In addition, the concept of random processes is covered in depth. The autocorrelation function, stationarity, and power spectral density are studied, along with extensions to multiple random processes. Particular attention is paid to wide-sense stationary processes, and the concept of power spectral density is introduced. Also explored is the filtering of wide-sense stationary random processes, including the essential properties of their autocorrelation function and power spectral density. Due to their significance in modeling noise in a communication system, Gaussian random processes are also covered.

Several issues in communication system design are highlighted. Specifically, the effects of transmission losses in a communication system and ways of addressing the related challenges are reviewed. A basic link budget analysis is performed. The effects of non-ideal amplifiers to combat transmission losses are demonstrated, and the loss in the signal-to-noise ratio at the amplifier output is quantified. The use of analog and regenerative repeaters for transmission over long distances is explored. Furthermore, time-division, frequency-division, and code-division multiple-access techniques are described.

A brief coverage of amplitude modulation (AM) and angle modulation techniques is provided. The basic principles of conventional AM, double-sideband suppressed carrier AM, single-sideband AM, and vestigial sideband AM are described both through time-domain and frequency-domain techniques. Frequency and phase modulation are described and their equivalence is argued. A comparison of different analog modulation techniques in terms of complexity, power, and bandwidth requirements is made. Conversion of analog signals into a digital form through sampling and quantization is studied. Proof of the sampling theorem is given. Scalar and vector quantizers are described. Uniform and non-uniform scalar quantizer designs are studied. The Lloyd-Max quantizer design algorithm is detailed. The amount of loss introduced by a quantizer is quantified by computing the mean square distortion, and the resulting signal-to-quantization noise ratio. Pulse code modulation (PCM) as a waveform coding technique, along with its variants – including differential PCM and delta modulation – is also studied.

Economics equates rationality with the satisfaction of a set of axioms. We discuss these axioms and the associated empirical evidence. Topics discussed include completeness and transitivity of preferences, limited attention, overconfidence, and whether humans can successfully construct the full sampling distributions. We then consider procedural rationality and the unreasonable cognitive requirements for solving simple dynamic programming problems. We examine alternatives to mathematical optimization in which people use simple rules of thumb (heuristics) to make decisions. We highlight the heuristics and biases program which clearly shows that the “as if” assumption in neoclassical economics is routinely violated. These heuristics include the representativeness heuristic, the gambler’s fallacy, the hot hand fallacy, the conjunction fallacy, the availability heuristic, the affect heuristic, the anchoring heuristic, base rate underweighting in Bayes’ law, conservatism from underweighting the likelihood of a sample, hindsight-bias, confirmation-bias, false consensus, and regression to the mean. Incentives do not eliminate biases. We also discuss the “great rationality debate.”

Chapter 7 acknowledges that, despite the best planning for positive engagement, students will still exhibit disengaged and disruptive behaviours. It examines the research to discuss which behaviours are the most common and the most difficult to manage in a classroom environment. It makes the distinction between frequent disengaged behaviour and rare ‘challenging’ behaviour discussed in Chapters 9 and 10.

Building on previous chapters, this chapter also discusses the best ways to prevent disengaged behaviours through implementing consistent classroom routines, structures and expectations, including the explicit teaching of expected behaviour. Ongoing strategies such as social-emotional learning to build strong relationships, low-key techniques to remind and redirect behaviours, class meetings to support student voice and engaging lessons are explored.

In September 2008, the oldest investment bank on Wall Street, Lehman Brothers, declared bankruptcy. Immediately, the world’s financial system seized up. Hundreds of billions of dollars’ worth of financial assets were frozen in place, the value of securities made uncertain, and the solvency of seemingly rock-solid financial institutions called into question. By the end of 2008, the United States’ economy was in freefall, shrinking at an annualized rate of 8%. Growth rates in other major industrialized economies also plummeted as well. The recession was so deep, and the recovery so labored that it took more than a decade for output to return to full employment levels. Figure 19.1 illustrates the situation rather dramatically.