সিগনাল এন্ড সিস্টেম

• ০০।
• ক) True
• খ) False

• ০১। δ(t) dt is a
• ক) Unit step
• খ) 0
• গ) r(t)
• ঘ) sinc

• ০২। The signal is
• ক) periodic for t > 0
• খ) non-periodic
• গ) periodic for t < 0
• ঘ) depends on t

• ০৩। δ(t - b) is a pulse function.
• ক) True
• খ) False

• ০৪। δ(t) is a
• ক) energy signal
• খ) power signal
• গ) neither energy nor power
• ঘ) none

• ০৫। (SI - A)^-1 = adj(sI - A)/det (sI - A)
• ক) True
• খ) False

• ০৬। (sI - A)^-1 is equal to
• ক) adj (sI - A)/det (sI - A)
• খ) det (sI - A)/adj(sI - A )
• গ) [adj (sI - A)] [det(sI - A)]
• ঘ) none of the above

• ০৭। A 1 kHz sinusoidal signal is ideally sampled at 1500 samples/sec and the sampled signal is passed through an ideal low pass filter with cut off frequency 800 Hz. The output signal has the frequency.
• ক) 0 Hz
• খ) 0.75 kHz
• গ) 0.5 kHz
• ঘ) 0.25 kHz

• ০৮। A box has 4 white and 3 red balls. Two balls are taken out in succession. What is the probability that both are white?
• ক)
• খ)
• গ)
• ঘ)

• ০৯। A casual LTI system is described by the difference equation
  2y[n] = ay[n - 2] - 2x[n] + βx[n -1]
  The system is stable only if
• ক) |a | = 2 |β| < 2
• খ) |a | > 2 |β| > 2
• গ) |a | < 2 any value of β
• ঘ) |β| < 2, any value of a

• ১০। A casual system having the transfer function is excited with 10 ∪(t). The time at which the output reaches 99% of its steady-state value is
• ক) 2.7 sec
• খ) 2.5 sec
• গ) 2.3 sec
• ঘ) 2.1 sec

• ১১। A complex wave is 5 + 5 sin ωt. Its rms value is
• ক) 7.07 V
• খ) 5 V
• গ) 10 V
• ঘ) 6.12 V

• ১২। A dice is tossed. The probability that either 1 or 2 will appear is
• ক)
• খ)
• গ)
• ঘ)

• ১৩। A discrete LTI system is non-casual if its impulse response is
• ক) an ∪(n - 2)
• খ) an-2 ∪(n)
• গ) an+2 ∪(n)
• ঘ) an ∪(n + 2)

• ১৪। A first order system will never be able to give a __________ response
  1. band stop
  2. band pass
  3. all pass
  Choose the correct option
• ক) 1, 2, 3 true
• খ) 1 and 3 true, 2 false
• গ) 1, 2 are true 3 is false
• ঘ) 1, 2 are false, 3 is true

• ১৫। A function having frequency f is to be sampled. The sampling time T should be
• ক)
• খ)
• গ)
• ঘ)

• ১৬। A function will have only sine terms if
• ক) f(t) = - f(t)
• খ) f(-t) = f(t)
• গ) f(-t) = -f(t)
• ঘ) none of the above

• ১৭। A gate function which occurs at t = t₀ and lasts for duration T can be written as
• ক) u (t - t0 - T)
• খ) u(t - t0) = u(t - t0 - T)
• গ) u(t - t0) - u(t - t0 - T)
• ঘ) u(t - t0) - u(t - t0 + T)

• ১৮। A linear discrete time system has the char. equation z³ - 0.81z = 0, the system is
• ক) stable
• খ) marginally stable
• গ) unstable
• ঘ) stability cannot be assessed from the given information

• ১৯। A linear system is characterized by H(ω) = Be^-2ω2 the system is physically
• ক) unrealizable
• খ) realizable
• গ) depends upon B
• ঘ) depends upon constant 2