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- Question
Options- Correct Answer
- unstable
ExplanationRouth array
There is negative number present in first column. Thus network is unstable.
Exam Questions Papers problems
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- 1. During transmission over a communicate channel, bit errors occur independently with probability
. If a block of 3 bits are transmitted, the probability of at most one bit error is equal to
Options- A.
- B.
- C.
Discuss
Correct Answer: none
Explanation:
Probability of no-error + probability one error
.
- 2. Consider a stable and causal system with impulse response h(t) and system function H(S). Suppose H(S) is rational, contains a pole at S = - 2, and does not have a zero at the origin. The location of all other poles and zero is unknown for each of the following statements. Let us determine whether statement is true or false.
- f[h(t) e-3t] converges
- h(t) has finite duration
- H(s) = H(- s)
Options
Discuss
Correct Answer: 1 - False, 2 - False, 3 - False, 4 - False
Explanation:
Statement 1 is false, since f{h(t)e3t} corresponds to the value of the Laplace transform of h(t) at s = 3.If this converges, it implies that s = - 3 is in the ROC.
A casual and stable system must always have its ROC to the right of all its poles. However, s = - 3 is not to the right of the pole at s = - 2.
Statement 2 is false, because it is equivalent to stating that H(0) = 0. This contradicts the fact that H(s) does not have a zero at the origin.
Statement 3 is false. If h(t) is of finite duration, then if its Laplace transform has any points in its ROC, ROC must be the entire s-plane.
However, this is not consistent with H(s) having a pole at s = - 2.
Statement 4 is false. If it were true, then H(s) has a pole at s = - 2, it must also have a pole at s = 2.
This is inconsistent with the fact that all the poles of a causal and stable system must be in the left half of the s-plane.
Options
Discuss
Correct Answer: 0.002
Explanation:
Distortion less
a = RG and Z0 = RG ?
.
Options- A.
- B.
- C.
- D.
Discuss
Correct Answer:
Explanation:
Since autocorrelation function and power spectral density bears a Fourier transform relation, then since required in frequency domain will five rectangular convolutions in time domain thus it is triangular function.- 5. If x1[n]
x1(z) with ROC = R1 and x2[n] x2(z) with ROC = R2 then ROC for x1[n] + x2[n] will be __________ (where Ri ? Region of convergence and x1[n] and x2[n] are causal).
Options
Discuss
Correct Answer: R1 ? R2
Explanation:
R1 ? R2, Suppose R1 for x1(n) be
Then ROC for x1(n) + x2(n)
R1 ? R2 (R1 < R2)
Then ROC for x1(n) + x2(n)
R1 ? R2(R1 < R2)
- 6. In the circuit shown, in switch S is open for a long time and is closed at t = 0. The current i(t) for t ? 0+ is
Options
Discuss
Correct Answer: i(t) = 0.5 - 0.125e-1000t A
Explanation:
i(f) = 0.5, i(i) = 0.75i(t) = Vr + (ii - ij)e-1/p = 0.5 - 0.125e-1000t .
- 7. Find Vx Vy Vz
Options
Discuss
Correct Answer: Vx = 6 Vy = 1 Vz = 3
Explanation:
Apply Mesh analysis
Apply KVL to mesh 2
-2 + Vy + 1 = 0
? Vy = 1
Apply KVL to mesh 1
? -8 + Vx + 2 = 0
? Vx = 6 V
Apply KVL to mesh 3
-1 + Vz -2 = 0
? Vz = 3 V.
- 8. The inverse of given Laplace transform is
Options
Discuss
Correct Answer: cos t
Explanation:
s = x2 - ex
x(t) = cos t.
- 9. Consider the common emitter amplifier shown below with the following circuit parameters: ? = 100, gm = 0.3861 A/V, r0 = ? rp = 259 ?, Rs = 1 k?, RB = 93 k?, RC = 250 ?, RL = 1 kW, C1 = ? and C2 = 4.7mF.
The resistance seen by the source Vs is
Options
Discuss
Correct Answer: 1258 ?
Explanation:
Zs = Rs + (RB || Brs)rc = 2.475 = 1.258 kV
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- 1. During transmission over a communicate channel, bit errors occur independently with probability