SULIT (EKT232) 2- SECTIONA BAHAGIANA Answer only ONE question in this section. J
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SULIT (EKT232) 2- SECTIONA BAHAGIANA Answer only ONE question in this section. Jawab hanya SATU soalan pada bahagian inl Question1 Soalan I (C3, COL, POI, PO2) Explain the following signal characteristics with suitable examples [Terangkan ciri-ciri signal berikut dengan contoh yang bersesuaian) a) i. Continuous-time signal and discrete-time signal ii. Causal signal and non-causal signal ii. Periodic signal and non-periodic signal Isyarat masa selarjar dan isyarat diskret) (2 Marks/Markah) (2 Marks/Markah) (2 Marks/Markah) Isyarat kausal dan isyarat bukan kausall [Isyarat berkala dan isyarat tidak berkala) (C3, COl, PO1, PO2) Sketch the waveforms of the following signals: Lakarkan corak gelombang bagi isyarat-isyarat berikt b) i.x(-4u) u(-t-1) (2 Marks/Markah) (2 Marks/Markah) (C4, COl, Po1, PO2) Compute the following convolution integral, y() = x()*h(), when x()= eit) and h()-tx() Sketch the relevant signal graphs to arrive at your answer [Kira pelingkaran kamiran yang berilkut, y()-x()h) eul)tu(). Lukiskan gambarajah isyarat yang bersesuaian untuk sampai kepada jawapan kamu.] c) (10 Marks/Markah)Explanation / Answer
1)a)Answer:
i)continuous-time signal:
A continuous-time signal is an infinite and uncountable set of numbers, as are the possible values each number can have
A continuous signal or a continuous-time signal is a varying quantity (a signal) whose domain, which is often time, is a continuum (e.g., a connected interval of the reals). That is, the function's domain is an uncountable set. The function itself need not be continuous. To contrast, a discrete time signal has a countable domain, like the natural numbers.
A signal of continuous amplitude and time is known as a continuous-time signal or an analog signal. This (a signal) will have some value at every instant of time. The electrical signals derived in proportion with the physical quantities such as temperature, pressure, sound etc. are generally continuous signals. Other examples of continuous signals are sine wave, cosine wave, triangular wave etc.
discrete-time signal:
A discrete signal or discrete-time signal is a time series consisting of a sequence of quantities. Unlike a continuous-time signal, a discrete-time signal is not a function of a continuous argument; however, it may have been obtained by sampling from a continuous-time signal.
ii)Casual signal:
Causal Signals are signals that are zero for all negative time. Causality in systems makes the most sense. Causality in signals doesn’t make that much sense. Causality in a systems determines whether a system relies on future information of a signal x[n+1]. When talking about “causality” in signals, we mean whether they are zero to the left of t=0 or zero to the right of t=0.
A causal signal is zero for t<0. However, the reason why this doesn’t really make sense is that if you have a signal, the time t=0 can be chosen arbitrarily.
A continuous time signal x(t), is said to be casual if : x(t)=0 for every t<0, the signal x(t) does not start before t=0.
Non casual signal:
Non-causal means that the response of the system needs to start before the excitation. For example, if you add an impulse to the input at a certain time T, a normal (causal) system will start responding from time T, T+1, T+2,…..
iii)Periodic signal:
A signal is said to be periodic if it is repeated over a cycle of time or a regular interval of time. ... Tangent (tan x) and co-tangent (cot x) signals are periodic signals with a periodicity ?. And a continuous signal with repeating pattern can be considered as periodic such as square saw tooth and triangular waves.
non-periodic signal:
A signalthat does not repeats its pattern over a period is called aperiodic signal or non periodic.
non-periodic signals, whose frequency components do change over time
A non-causal system would start its response before the input, e.g. T-10, T-9, … T, T+1, …
This is of course not a natural system because it would need to predict the future and start responding before the input.
A continuous time signal x(t), is said to be non-casual if : x(t)=0 for every t>0, the signal x(t) start before t=0.
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