Digital Electronic MCQ Set 1
1. What is the value of |TN(±1)|?
a) 0
b) -1
c) 1
d) None of the mentioned
Answer
Answer: c [Reason:] We know that a chebyshev polynomial of degree N is defined as
TN(x) = cos(Ncos-1x), |x|≤1
cosh(Ncosh-1x), |x|>1
Thus |TN(±1)|=1.
2. The chebyshev polynomial is oscillatory in the range |x|<∞.
a) True
b) False
Answer
Answer: b [Reason:] The chebyshev polynomial is oscillatory in the range |x|≤1 and monotonic outside it.
3. If NB and NC are the orders of the Butterworth and Chebyshev filters respectively to meet the same frequency specifications, then which of the following relation is true?
a) NC=NB
b) NC<NB
c) NC>NB
d) Cannot be determined
Answer
Answer: b [Reason:] The equi-ripple property of the chebyshev filter yields a narrower transition band compared with that obtained when the magnitude response is monotone. As a consequence of this, the order of a chebyshev filter needed to achieve the given frequency domain specifications is usually lower than that of a Butterworth filter.
4. The chebyshev-I filter is equi-ripple in pass band and monotonic in the stop band.
a) True
b) False
Answer
Answer: a [Reason:] There are two types of chebyshev filters. The Chebyshev-I filter is equi-ripple in the pass band and monotonic in the stop band and the chebyshev-II filter is quite opposite.
5. What is the equation for magnitude frequency response |H(jΩ)| of a low pass chebyshev-I filter?
Answer
Answer: d [Reason:] The magnitude frequency response of a low pass chebyshev-I filter is given by
where ϵ is a parameter of the filter related to the ripple in the pass band and TN(x) is the Nth order chebyshev polynomial.
6. What is the number of minima’s present in the pass band of magnitude frequency response of a low pass chebyshev-I filter of order 4?
a) 1
b) 2
c) 3
d) 4
Answer
Answer: b [Reason:] In the magnitude frequency response of a low pass chebyshev-I filter, the pass band has 2 maxima and 2 minima(order 4=2 maxima+2 minima).
7. What is the number of maxima present in the pass band of magnitude frequency response of a low pass chebyshev-I filter of order 5?
a) 1
b) 2
c) 3
d) 4
Answer
Answer: c [Reason:] In the magnitude frequency response of a low pass chebyshev-I filter, the pass band has 3 maxima and 2 minima(order 5=3 maxima+2 minima).
8. The sum of number of maxima and minima in the pass band equals the order of the filter.
a) True
b) False
Answer
Answer: a [Reason:] In the pass band of the frequency response of the low pass chebyshev-I filter, the sum of number of maxima and minima is equal to the order of the filter.
9. Which of the following is the characteristic equation of a Chebyshev filter?
d) None of the mentioned
Answer
Answer: a [Reason:] We know that for a chebyshev filter, we have
10. The poles of HN(s).HN(-s) are found to lie on:
a) Circle
b) Parabola
c) Hyperbola
d) Ellipse
Answer
Answer: d [Reason:] The poles of HN(s).HN(-s) is given by the characteristic equation 1+ϵ2TN2(s/j)=0.
The roots of the above characteristic equation lies on ellipse, thus the poles of HN(s).HN(-s) are found to lie on ellipse.
11. If the discrimination factor ‘d’ and the selectivity factor ‘k’ of a chebyshev I filter are 0.077 and 0.769 respectively, then what is the order of the filter?
a) 2
b) 5
c) 4
d) 3
Answer
Answer: b [Reason:] We know that the order of a chebyshev-I filter is given by the equation,
N=cosh-1(1/d)/cosh-1(1/k)=4.3
Rounding off to the next large integer, we get N=5.
Digital Electronic MCQ Set 2
1. If δ1 represents the ripple in the pass band for a chebyshev filter, then which of the following conditions is true?
Answer
Answer: a [Reason:] Let us consider the design of a low pass filter with the pass band edge frequency ωP and the ripple in the pass band is δ1, then from the general specifications of the chebyshev filter, in the pass band the filter frequency response should satisfy the condition
2. If the filter has symmetric unit sample response with M odd, then what is the value of Q(ω)?
a) cos(ω/2)
b) sin(ω/2)
c) 1
d) sinω
Answer
Answer: c [Reason:] If the filter has a symmetric unit sample response, then we know that
h(n)=h(M-1-n)
and for M odd in this case, Q(ω)=1.
3. If the filter has anti-symmetric unit sample response with M odd, then what is the value of Q(ω)?
a) cos(ω/2)
b) sin(ω/2)
c) 1
d) sinω
Answer
Answer: d [Reason:] If the filter has a anti-symmetric unit sample response, then we know that
h(n)= -h(M-1-n)
and for M odd in this case, Q(ω)=sin(ω).
4. In which of the following way the real valued desired frequency response is defined?
a) Unity in stop band and zero in pass band
b) Unity in both pass and stop bands
c) Unity in pass band and zero in stop band
d) Zero in both stop and pass band
Answer
Answer: c [Reason:] The real valued desired frequency response Hdr(ω) is simply defined to be unity in the pass band and zero in the stop band.
5. The error function E(ω) should exhibit at least how many extremal frequencies in S?
a) L
b) L-1
c) L+1
d) L+2
Answer
Answer: d [Reason:] According to Alternation theorem, a necessary and sufficient condition for Pω) to be unique, best weighted chebyshev approximation, is that the error function E(ω) must exhibit at least L+2 extremal frequencies in S.
6. The filter designs that contain maximum number of alternations are called as:
a) Extra ripple filters
b) Maximal ripple filters
c) Equi ripple filters
d) None of the mentioned
Answer
Answer: b [Reason:] In general, the filter designs that contain maximum number of alternations or ripples are called as maximal ripple filters.
7. Remez exchange algorithm is an iterative algorithm used in error approximation.
a) True
b) False
Answer
Answer: a [Reason:] Initially, we neither know the set of external frequencies nor the parameters. To solve for the parameters, we use an iterative algorithm called the Remez exchange algorithm, in which we begin by guessing at the set of extremal frequencies.
8. When |E(ω)|≤δ for all frequencies on the dense set, the optimal solution has been found in terms of the polynomial H(ω).
a) True
b) False
Answer
Answer: a [Reason:] |E(ω)|≥δ for some frequencies on the dense set, then a new set of frequencies corresponding to the L+2 largest peaks of |E(ω)| are selected and computation is repeated. Since the new set of L+2 extremal frequencies are selected to increase in each iteration until it converges to the upper bound, this implies that when |E(ω)|≤δ for all frequencies on the dense set, the optimal solution has been found in terms of the polynomial H(ω).
9. In Parks-McClellan program, an array of maximum size 10 that specifies the weight function in each band is denoted by?
a) WTX
b) FX
c) EDGE
d) None of the mentioned
Answer
Answer: a [Reason:] FX denotes an array of maximum size 10 that specifies the weight function in each band.
10. The filter designs which are formulated using chebyshev approximating problem have ripples in?
a) Pass band
b) Stop band
c) Both of the mentioned
d) None of the mentioned
Answer
Answer: c [Reason:] The chebyshev approximation problem is viewed as an optimum design criterion on the sense that the weighted approximation error between the desired frequency response and the actual frequency response is spread evenly across the pass band and evenly across the stop band of the filter minimizing the maximum error. The resulting filter designs have ripples in both pass band and stop band.
11. If the filter has symmetric unit sample response with M even, then what is the value of Q(ω)?
a) cos(ω/2)
b) sin(ω/2)
c) 1
d) sinω
Answer
Answer: a [Reason:] If the filter has a symmetric unit sample response, then we know that
h(n)=h(M-1-n)
and for M even in this case, Q(ω)= cos(ω/2).
Digital Electronic MCQ Set 3
1. Dynamic memory cells use ___ as the storage device.
a) The reactance of a transistor
b) The impedance of a transistor
c) The capacitance of a transistor
d) None of the Mentioned
Answer
Answer: c [Reason:] Capacitance of a transistor prevents from loss of information in a dynamic memory cell.
2. To store 1-bit of information, how many transistor is/are used
a) 1
b) 2
c) 3
d) 4
Answer
Answer: a [Reason:] Only one bit transistor is needed to store 1-bit of information.
3. Static memory holds data as long as
a) AC power is applied
b) DC power is applied
c) Capacitor is fully charged
d) None of the Mentioned
Answer
Answer: b [Reason:] In any semiconductor equipment, AC power can’t be supplied directly. So, static memory holds the data as long as DC power is applied.
4. The example of dynamic memory is
a) CCD
b) Semiconductor dynamic RAM
c) Both CCD and semiconductor dynamic RAM
d) None of the Mentioned
Answer
Answer: c [Reason:] The examples of dynamic memories are CCD and semiconductor dynamic RAM because the contents of both the memories changes with time.
5. In dynamic memory, CCD stands for
a) Charged Count Devices
b) Change Coupled Devices
c) Charge Coupled Devices
d) None of the Mentioned
Answer
Answer: b [Reason:] In dynamic memory, CCD stands for Charge Coupled Devices.
6. Volatile memory refers to
a) The memory whose loosed data is achieved again when power to the memory circuit is removed
b) The memory which looses data when power to the memory circuit is removed
c) The memory which looses data when power to the memory circuit is applied
d) The memory whose loosed data is achieved again when power to the memory circuit is applied
Answer
Answer: b [Reason:] Volatile means ‘liable to change rapidly’ and volatile memory refers to the memory which looses data rapidly when power to the memory circuit is removed.
7. Non-volatile memory refers to
a) The memory whose loosed data is retained again when power to the memory circuit is removed/applied
b) The memory which looses data when power to the memory circuit is removed
c) The memory which looses data when power to the memory circuit is applied
d) The memory whose loosed data is achieved again when power to the memory circuit is applied
Answer
Answer: a [Reason:] Non-volatile means ‘not volatile’ and non-volatile memory refers to the memory which retains the data even if there is a break in the power supply.
8. The example of non-volatile memory device is
a) Magnetic Core Memory
b) Read Only Memory
c) Random Access Memory
d) Both Magnetic Core Memory and Read Only Memory
Answer
Answer: d [Reason:] The examples of non-volatile memory devices are Magnetic Core Memory & ROM because both have capability to retain the data.
9. Based on material used for construction, memory devices are classifieds into ________ categories.
a) 2
b) 3
c) 4
d) 5
Answer
Answer:a [Reason:] Based on material used for construction, memory devices are classifieds into two categories, viz., Magnetic and Semiconductor memory.
10. Magnetic recording is the process of
a) Storing data symmetrically
b) Storing data sequentially
c) Storing data magnetically
d) Both storing data symmetrically and
Answer
Answer: c [Reason:] Magnetic recording is the process of storing data magnetically. Hard disk, floppy disk, magnetic tape are the examples of magnetic recording process.
11. Magnetic drum is a storage medium using
a) The surface of a jumping magnetic drum
b) The surface of a rotating magnetic drum
c) The surface of a stopped magnetic drum
d) None of the Mentioned
Answer
Answer: b [Reason:] Magnetic drum is a storage medium using the surface of a rotating magnetic drum which have tendency to hold the data.
12. Magnetic core is the digital memory in which data is stored magnetically in individual cores operated by
a) Up and down select wires
b) Row and column select wires
c) Serial and parallel select wires
d) None of the Mentioned
Answer
Answer: b [Reason:] Magnetic core is the digital memory in which data is stored magnetically in individual cores operated by row and column select wires, with data obtained from sense wire.
13. By which technology, semiconductor memories are constructed?
a) PLD
b) LSI
c) VLSI
d) Both LSI and VLSI
Answer
Answer: d [Reason:] Generally, semiconductor memories are constructed using LSI/VLSI because these are made up of NMOS, CMOS, BJT etc.
Digital Electronic MCQ Set 4
1. If the number of bits in the sum exceeds the number of bits in each added numbers, it results in
a) Successor
b) Overflow
c) Underflow
d) None of the Mentioned
Answer
Answer: b [Reason:] If the number of bits in the sum exceeds the number of bits in each added numbers, it results in overflow and is also known as excess-one.
2. An overflow is a
a) Software problem
b) Hardware problem
c) User input problem
d) None of the Mentioned
Answer
Answer: b [Reason:] An overflow is a hardware problem. It is not able to show correct result because of sign changes.
3. An overflow occurs in
a) MSD position
b) LSD position
c) Middle position
d) Never occurs
Answer
Answer: a [Reason:] An overflow occurs at Most Significant Digit position.
4. Logic circuitry is used to detect
a) Underflow
b) MSD
c) Overflow
d) LSD
Answer
Answer: c [Reason:] To check the overflow logic circuitry is used in each case.
5. 1’s complement can be easily obtained by using
a) Comparator
b) Inverter
c) Adder
d) Subtractor
Answer
Answer: b [Reason:] With the help of inverter the 1’s complement is easily obtained. Since, during the operation of 1’s complement 1 is converted into 0 and vice-versa and this is well suited for the inverter.
6. The advantage of 2’s complement system is that
a) Only one arithmetic operation is required
b) Two arithmetic operations are required
c) No arithmetic operations are required
d) None of the Mentioned
Answer
Answer: a [Reason:] The advantage of 2’s complement is that only one arithmetic operation is required for 2’s complement’s operation and that is either addition or subtraction.
7. The 1’s complements requires
a) Two operations
b) One operations
c) Three operations
d) None of the Mentioned
Answer
Answer: a [Reason:] Two operations are required for 1’s complement operation. These are conversion of binary numbers and addition/subtraction.
8. Which one is used for logical manipulations ?
a) 2’s complement
b) 9’s complement
c) 1’s complement
d) 10’s complement
Answer
Answer: c [Reason:] For logical manipulations 1’s complement is used.
9. For arithmetic operations only
a) 1’s complement is used
b) 2’s complement
c) 3’s complement
d) 9’s complement
Answer
Answer: b [Reason:] Only 2’s complement is used for arithmetic operations.
10. The addition of +19 and +43 results as ___ in 2’s complement system.
a) 11001010
b) 101011010
c) 00101010
d) 00111110
Answer
Answer: d [Reason:] None.
Digital Electronic MCQ Set 5
1. MOS families includes
a) PMOS and NMOS
b) CMOS and NMOS
c) PMOS, NMOS and CMOS
d) EMOS, NMOS and PMOS
Answer
Answer: c [Reason:] Metal Oxide Semiconductor families includes PMOS, NMOS and CMOS.
2. CMOS refers to
a) Continuous Metal Oxide Semiconductor
b) Complementary Metal Oxide Semiconductor
c) Centred Metal Oxide Semiconductor
d) None of the Mentioned
Answer
Answer: b [Reason:] CMOS refers to Complementary Metal Oxide Semiconductor.
3. Propagation delay is defined as
a) the time taken for the output of a gate to change after the inputs have changed
b) the time taken for the input of a gate to change after the outputs have changed
c) the time taken for the input of a gate to change after the intermediates have changed
d) the time taken for the output of a gate to change after the intermediates have changed
Answer
Answer: a [Reason:] Propagation delay is defined as the time taken for the output of a gate to change after the inputs have changed.
4. Propagation delay times can be divided as
a) t(PLH) and t(LPH)
b) t(LPH) and t(PHL)
c) t(PLH) and t(PHL)
d) None of the Mentioned
Answer
Answer: c [Reason:] Propagation delay times can be divided as: t(PLH) and t(PHL).
5. The delay times are measured between the ___ % voltage levels of the input and output waveforms.
a) 50
b) 75
c) 25
d) 100
Answer
Answer: a [Reason:] The average of the two propagation delays is given by (t1 + t2)/2, which gives the intermediate value. So, the delay times are measured between the 50% voltage levels of the input and output waveforms.
6. Power Dissipation in DIC is expressed in
a) Watts or kilowatts
b) Milliwatts or nanowatts
c) DB
d) None of the Mentioned
Answer
Answer: b [Reason:] Power Dissipation in DIC is expressed in milliwatts or nanowatts.
7. Fan-in is defined as
a) the number of outputs connected to gate without any degradation in the voltage levels
b) the number of inputs connected to gate without any degradation in the voltage levels
c) the number of outputs connected to gate with degradation in the voltage levels
d) the number of inputs connected to gate with degradation in the voltage levels
Answer
Answer: b [Reason:] Fan-in is defined as the number of inputs connected to gate without any degradation in the voltage levels. For example, an eight-input gate requires one Unit Load per input. It’s fan-in is 8.
8. The maximum noise voltage that may appear at the input of a logic gate without changing the logical state of its output is termed as
a) Noise Margin
b) Noise Immunity
c) White Noise
d) None of the Mentioned
Answer
Answer: b [Reason:] The maximum noise voltage that may appear at the input of a logic gate without changing the logical state of its output is termed as noise immunity.
9. Depending upon the flow of current from the output of one logic circuit to the input of another the logic families can be divides into ___ categories.
a) 2
b) 3
c) 4
d) 5
Answer
Answer: a [Reason:] Depending upon the flow of current from the output of one logic circuit to the input of another the logic families can be divides into two categories and they are current sourcing and current sinking.
10. Fan-in and Fan-out are the characteristics of
a) Registers
b) Logic families
c) Flip flop
d) Combinational Circuits
Answer
Answer: b [Reason:] Fan-in and Fan-out are the characteristics of logic families.
