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is highly visualized, interactive and use-friendly. It is also flexible and expandable-new modules can easily be added to meet the future needs of further development.
   In this article, https://www.51lunwen.org/yingyulunwengeshi/ some typical modules of classical simulation experiments in Signal and Systems and how they are used in the teaching are described.

SOME TYPICAL EXPERIMENT MODULES
Spectral Characteristics of Pulse Trains
Spectral characteristics of periodic rectangular pulse signals (or signals of other shapes) are demonstrated and experiments are designed. This module assists the learning of basic concepts and properties of the spectra of several typical waveforms including rectangular pulses, sawtooth   signals, triangular pulses, etc., and demonstrates effects of wave parameters such as pulse width and pulse repetition rate upon the spectra.
Students are first asked to make careful observation. They will find that the spectrum of single rectangular pulse is a continuous sinc function, while a periodic pulse train has a discrete spectrum with a sinc envelope. Subsequent experiments and questions will help students understand the main characteristics of the spectra, and their relationship with basic parameters of the time domain waveforms, i.e., pulse shape, pulse width, and repetition rate.
Experiment 1: Move the slide with mouse to change the duty cycle while keeping the frequency constant. This is equivalent to changing the pulse width. The spacing between spectral lines will not change because the repetition rate is preserved. However, a change in the sinc envelope with the pulse width can be observed. When the pulse width decreases, the main-lobe of the sinc function will be widened, and the order number of the harmonic with zero amplitude will rise. In the meantime, convergence of the harmonic amplitudes toward zero is slowed down, implying that the signal bandwidth is increased.
Experiment 2: Click mouse on the waveform and drag it to change the pulse repetition rate or directly enter a new value of the period in the provided dialogue box keeping the pulse width unchanged[1]. In this case, the sinc envelope will not change, and the spacing between spectral lines will vary with the period. The spacing decreases as the period becomes larger due to the fact that the spectral spacing equals the fundamental frequency.
In summary, this experiment visualizes the spectral characteristics of a rectangular pulses train, demonstrates main points of the issue such as relationship between pulse width and bandwidth. It helps students deepen their understanding of Fourier expansion of periodic signals.

Frequency Response of System
Frequency responses of systems are demonstrated and experiments are designed to assist learning of the characteristics of frequency response and the effect of positions of zeros and poles on the frequency response.
    The first observation is made on the fundamental relationship between the nature of system and the periodicity of its frequency response: a continuous system has an aperiodic frequency response, while a discrete system has a periodic frequency response[2]. Experiments and questions are designed to help students learn the main characteristics of frequency response, and their relationship with the system’s zeros and poles.
    Experiment 1: Click the pull down menu Choose Zeros and Poles of Continuous System to define the positions o本论文由英语论文网提供整理，提供论文代写，英语论文代写，代写论文，代写英语论文，代写留学生论文，代写英文论文，留学生论文代写相关核心关键词搜索。