Here, we’d like you to show you how to do one task many ways. This is a favorite device of exam-writers; this kind of question lets the teachers feel that there’s some coherence in the digital material. Students may not feel the same way about these questions.

In this chapter you will configure the Timer/Counter peripheral to interrupt the CPU at a constant rate to output a sampled sine wave from the DAC. On the way, you will land on the Moon.

Deliberate rolling-off of op-amp gain as frequency rises: used to assure stability of feedback circuits despite dangerously-large phase shifts that occur at high frequencies.

In the previous lab, you configured the SAMD21’s internal 10-bit Digital-to-Analog converter to output an analog voltage to an I/O pin and then used the DAC to synthesize a 128 point sine wave. While this worked, updating the DAC in a loop did not provide precise control over the frequency of the output signal and the process of sending data values to the DAC consumed all the processor CPU cycles. This design also did not ensure that samples were output at constant time intervals.

Prehistory: before the microprocessor: Yes, there was a time when computers roamed the Earth, but were not based on microprocessors. In the 1930s electromechanical computers were built using relays; some were true “Turing machines,” fully programmable.

The notion of multiplexing, or time-sharing, is more general and more important than the piece of hardware called a multiplexer (or “mux”). You won’t often use a mux, but you use multiplexing continually in any computer, and in many data-acquisition schemes.

Until now, as we have said in Chapter 8N, we have treated positive feedback as evil or as a mistake: it’s what you get when you get confused about which op-amp terminal you’re feeding. Today you will qualify this view: you will find that positive feedback can be useful: it can improve the performance of a comparator; it can be combined with negative feedback to make an oscillator (“relaxation oscillator”: positive feedback dominates there); or to make a negative impedance converter (this we will not build, but see AoE §4.107, Fig. 4.104: there, negative feedback dominates).

This chapter introduces the notation used in the book and discusses the mixed integer programming (MIP) computational framework in which heuristics are developed, used, and evaluated. The chapter starts by formally definining MIP and presenting the basic complete algorithms to solve it. Then, the more important building block concepts at the core of primal heuristics are presented, as well as the way in which they are incorporated in the MIP framework and their impact.

Adjust frequency so as to get a useful image: too high, and you won’t allow time enough to see the waveform move far; too low, and you’ll see the full waveform, but using just a small portion of the scope screen, and thus your time measurements will be only approximate.

The sort of problem we mean to solve with the most important of today’s circuits is the conversion of a sinusoidal power supply voltage – AC coming from the wall supply (often called “line” voltage) – to a constant DC level.

In this chapter the use of the finite element method in hull girder analysis and design is described. Quasi-static and vibration analysis of the hull girder are considered. The use of approximate simplified quasi-static analysis and of linear elastic finite element analysis using both 2D and 3D models are discussed. The implementation of FE models to the residual and ultimate strength is described and various approaches compared. FE models used in vibration response are considered and the matrix equations of dynamic equilibrium given. Free vibration and forced vibration response are discussed and vibration modes resulting from main engine excitation described. Rule requirements for the implementation of the FEM are discussed. The rational design of the hull girder using a classification society approach is described. Finite element codes used in ship structural analysis and design are mentioned and their capabilities compared. Two case studies are described in detail. The first of these concerns the use of nonlinear elasto-plastic analysis to determine the ultimate strength of a bulk carrier in the alternate hold loading condition. The second study presents a comparison of the dynamic response of single and double-skin bulk carriers involved in a collision incident.

These are just lines that make lots of stops, picking up and letting off anyone who needs a ride. The origin of the word is the same as the origin of the word for the thing that rolls along city streets.

How many bits does the converter need? We can tolerate slices that are two parts in 10,000 wide, or 1/5k. 12 bits give 4K slices (4096), and give an error of 1/8K or 0.012%: this does not quite satisfy the specification.

In the previous microcontroller labs you controlled the I/O ports directly to scan a matrix keyboard, programmed a timer to interrupt at regular intervals to output a sine wave at a specific frequency, and initiated SPI communications with a LCD display to show text messages. In this lab you are going to integrate these elements into a jukebox that plays children’s lullabies using an RTOS.