tut 4 complete sol - 4-1 The term sequence may be used to...

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4-1- The term “sequence” may be used to refer to a discrete-time signal. What is the reason(s)? Also, terms such as wave, waveform, signal, and function are used for referring to CT and DT entities. Make a table listing terms, including sequence, are used in this context and give very brief explanations for each. Because a discrete-time signal contains actually a set of points or samples, they are forming a sequence. 4-2- Briefly discuss the difference between an ideal continuous to discrete converter and a practical analogue to digital converter. Include corresponding block diagram representations for both systems in your explanations. Solution : A Continuous to Discrete Converter (C-to-D) are used to convert a continuously varying signal such as speech or audio to a discrete time signal. This process is called sampling. The discrete time signal is obtained by taking values of the continuous time signal at equally spaced time instants. x[n] = x(nTs) ; Where Ts is the sampling period. The A-to-D conversion is a physical approximation to the ideal C-to-D converter. An A-to-D converter produces only finite precision numbers as samples of the input signal (quantized to a limited number of bits), while the ideal C-to-D converter produces samples with infinite precision. A-to-D converters differ from ideal C-to-D converters because of real-world problems such as: 1. Amplitude quantization to number of bits available (12 or 16 bits) 2. Jitter in the sampling times 3. Other factors those are difficult to analyse These factors can be made negligible with careful design, and hence a practical A/D converter offers sufficiently accurate operation as an ideal C-to-D converter. An Ideal C-to-D converter Wave An entity describes changes of natural phenomenon Waveform A curve presents wave visually Signal A kind of information that can be processed and transmitted Function An entity obtains and processes inputs and give outputs sequence A set of points or samples that contain information
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An A-to-D converter 4-3- Discrete-time frequency is dimensionless. Provide some explanations through comparing it with angular frequency (circular or radian frequency) and show how an identical discrete-time frequency could be resulted from an infinite number of continuous-time sinusoid waves. Discrete-time frequency is a dimensionless quantity; consistent with the fact that the index “n” in x[n] is dimensionless. The unit of discrete-time frequency is radian and the unit of angular frequency is radians/sec. Suppose that identical discrete-time frequency is ω(hat), ω(hat) =ω*Ts. 4-4- Aliasing is solely due to the fact that trigonometric functions are periodic with
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This note was uploaded on 04/15/2010 for the course ECTE 906 taught by Professor Pd during the Three '10 term at University of Wollongong, Australia.

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tut 4 complete sol - 4-1 The term sequence may be used to...

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