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The role of PSpice in the engineering teaching environment Simulation software tools have been shown to be effective in communicating abstract ideas to students. Several studies have shown that the performance of students who used simulation software scored higher marks on written exams, when compared to those who used laboratory methods only” 5/23/2017 10th International Conference on Engineering Education F1C 1 Capacitive reactance • Basic principles can be explored by simple circuits. The following example looks at reactance and the phase delays between I and V. • 5/23/2017 10th International Conference on Engineering Education F1C 2 Capacitive reactance plot PSpice allows the student to measure reactance at any frequency. Open circuit Short circuit 5/23/2017 10th International Conference on Engineering Education F1C 3 Time delay and Phase difference Students find time delay a much easier concept to understand than phase delay. The student may convert the measured time delay to a phase delay as: T t 360 xt 360 x25 ms 900 360 T 100 ms 5/23/2017 10th International Conference on Engineering Education F1C 4 Terminating a Transmission line This example shows a transmission terminated with different resistances, i.e. an open circuit to a short circuit. 5/23/2017 10th International Conference on Engineering Education F1C 5 Standing waves and VSWR Standing waves occur when lines are incorrectly terminated and are quantified by voltage standing wave ratio (VSWR). 5/23/2017 10th International Conference on Engineering Education F1C 6 The use of Macros in PSpice Macros extend the horizons of PSpice greatly. Here we examine signal errors in received digital signals corrupted by noise. A macro contains a series of steps, or equations 5/23/2017 10th International Conference on Engineering Education F1C 7 Noise corrupts digital signal such that a ‘1’ may be misinterpreted as a ‘0’, and vice versa. However, we need to apply probabilities since we cannot say where and when these errors occur. 5/23/2017 10th International Conference on Engineering Education F1C 8 Gaussian distribution and errors A binary data signal corrupting by noise has a probability distribution described by the equation: 1 ( vn vd )2 / 2vn Pe (vd , vn ) e vn 2 Pe (vd , vn ) 1 ( v v )2 / 2vn e n d vn 2 To quantify these errors we need to look at the probability of these errors existing over a certain time period. A text editor, such as Notepad, can be used to create the following macro: • Gaussian1(vd,vn)=(1/(sqrt(rms(vn)*rms(vn)*2*pi)))*exp(-((vd-2)*(vd2)/(2*rms(vn)*rms(vn)))) 5/23/2017 10th International Conference on Engineering Education F1C 9 Gaussian distribution 5/23/2017 10th International Conference on Engineering Education F1C 10 Implementing a Hilbert transform A Hilbert transform introduces a constant 90-degree across the passband region, and here it is implemented using a Finite Impulse Response (FIR) digital filter 5/23/2017 10th International Conference on Engineering Education F1C 11 Digital filter impulse response 5/23/2017 10th International Conference on Engineering Education F1C 12 Magnitude and phase responses 5/23/2017 10th International Conference on Engineering Education F1C 13 Sixth-order active filter 5/23/2017 10th International Conference on Engineering Education F1C 14 Histogram and frequency response 5/23/2017 10th International Conference on Engineering Education F1C 15 16-Quad Amplitude Modulator 5/23/2017 10th International Conference on Engineering Education F1C 16 16-QAM scatter diagram 5/23/2017 10th International Conference on Engineering Education F1C 17 Conclusions A worrying trend in engineering education is a reduction in teaching fundamental principles. The paper attempted to demonstrate how PSpice can help with this, and do so with a minimum of mathematical rigor. The student can examine complex sub systems and consider the problems associated with matching sub-systems connected together, a task not easily done in practice Thank you 5/23/2017 10th International Conference on Engineering Education F1C 18