## [MCQ’s] Filter Design

#### Module 1

1.The order of the filter which gives maximally flat LPF response such
thatit has a 3dB bandwidth of 400MHz and attenuation of 20dB at
1GHz. Thefilter is to beconnected to 50ohms source and load
impedances.

a)6
b)5
c)4
d)3

2.How many elements are required to design a Butterworth low pass filter
with a cut-off frequency of 50MHz, if the filter must provide at least
50dB of attenuation at 150MHz?

a)4
b)6
c)5
d)7

3.To design a Chebychev high pass filter with cutoff frequency 100
MHz, which will offer 45dB attenuation at 50 MHz, we need
___________________number of elements

a)2
b)4
c)5
d)6

4.For the Butterworth filter of order N
a)The roll off is more than maximally flat filter
b)The roll off is less than maximally flat filter
c)The roll off is equal to maximally flat filter

5.For a maximally flat LPF the insertion loss
a)Increases by 20NdB/decade in the stopband
b)Increases by 30NdB/decade in the stopband
c)Decreases by 20NdB/decade in the stopband
d)Decreases by 30NdB/decade in the stopband

6.A 3-dB, equi-ripple low pass filter with a cutoff frequency of 2 GHz,
50- impedance level, and at least 15-dB insertion loss at 3 GHz.

a)10.22pF, 5.34nH, 10.22pF
b)5.33pF, 2.83nH, 5.33pF
c)4.2pF,1.3nH,4.2pF
d)7.6pF, 6.3nH,7.6pF

7.For low pass filter with cut off frequency of 5MHz and impedance of
75ohms, infinite attenuation pole is at 5.05 MHz, the value of m for m
derived sharp cutoff section is

a)m=0.6
b)m=0.25
c)m=0.14
d)m=0.35

8.A LPF with cut off 2GHz and impedance 50ohms is to be scaled to
75ohms. The element values were 0.984pF,6.43nH,0.984pF. The new
values will be

a)8.33pF, 11.5nH, 8.33pF
b)0.655pF, 9.6nH, 0.655pF
c)5.6pF, 9.7nH, 5.6pF
d)1.5pF, 4.2nH,1.5pF

9.A LPF with cut off 2GHz and impedance 50ohms is to be scaled to 3GHz.
The element values were 0.984pF,6.43nH,0.984pF. The new values will
be

a)0.656pF,4.2nH,0.656pF
b)0.655pF, 9.6nH, 0.655pF
c)5.6pF, 9.7nH, 5.6pF
d)1.5pF, 4.2nH,1.5pF

10.A LPF with cut off 2GHz and impedance 50ohms is to be converted
to L-C-L combination. The element values were
0.984pF,6.43nH,0.984pF. The new values will be

a)5.6nH, 9.7pF, 5.6nH
b)
c)
d)

#### Module 2

1.A maximum gain amplifier at the frequency of 3GHz, if selected BJT has
the following S parameters at VCE=4V and IC=5mA with 50ohms as a
reference impedance.
S11=0.55∟1550
S21=5.5∟1800
S12=0
S22=0.36∟200
Then the maximum gain will be

a)15dB
b)17dB
c)20db
d)22db

2.The matching network for maximum gain amplifier design at the
frequency of 3GHz, for a BJT having S parameters at VCE=4V and
IC=5mA with 50ohms as a reference impedance.
S11=0.55∟1550
S21=5.5∟1800
S12=0
S22=0.36∟200

will have source and load matching network reflection coefficient
as follows
a)τS=0.55∟-1550,τL=0.36∟-200
b)τS=5.5∟1800, τL=0
c)τS=0 , τL=0.36∟-200

3.A GaAsFET that has the following S parameters at 2GHz in a 50ohms S11=0.65∟-950
S21=5∟1150
S12=0.5∟400
S22=0.8∟-350
The k and Δvalue equal to

a)k=3.6 and Δ=0.4∟-450
b)k=1.18 and Δ=2.4∟-370
c)k=8.9 and Δ=0.24∟370
d)k=6.4 and Δ=2∟490

4.A GaAsFET that has the following S parameters at 2GHz in a 50ohms S11=0.65∟-950
S21=5∟1150
S12=0.5∟400
S22=0.8∟-350
The centre of the input stability circle and radius of the input stability circle is

5.A GaAsFET that has the following S parameters at 2GHz in a 50ohms S11=0.65∟-950
S21=5∟1150
S12=0.5∟400
S22=0.8∟-350
The centre of the output stability circle and radius of the input stability circle is

6.A GaAs MESFET has VDS=3V, IDS=30mA for 8GHz with 50ohms reference
S11=0.52 ∟-1450
S12=0
S21=2.56 ∟1700
S22=0.48 ∟-200
The centre and radius of the Gain cirlce GS=1.37dB is given by magnitude

7.Stability of an amplifier is it’s effectiveness in maintaining
a)All operating characteristics inspite of large changes in the environment
b)Maximum operating characteristics inspite of large changes in the environment
c)Nominal operating characteristics inspite of large changes in the environment
d)Minimum operating characteristics inspite of large changes in the environment

8.A microwave transistor has the following S parameters at 10GHz, with a 50ohms reference impedance.
S11=0.45∟1500
S12=0.01∟-100
S21=2.05∟100
S22=0.40∟-1500
The source impedance is ZS=20ohm and the load impedance is ZL=30ohm. Compute the transducer gain

a)7.39dB
b)5.4dB
c)8.7dB
d)8.12dB

9.In receiver applications the pre amplifier has
a)Maximum Possible gain
b)low noise figure
c)High power amplification
d)Maximum noise figure

10.For a given transistor mimimum noise figure and maximum gain
a)is possible
b)is impossible
c)is a tradeoff between gain and noise figure
d)settles with a choice of maximum gain

11.A GaAs MESFET has VDS=3V, IDS=30mA for 8GHz with 50ohms reference
S11=0.52 ∟-1450
S12=0.06 ∟-200
S21=2.56 ∟1700
S22=0.48 ∟-200
Rn=20ohm and τopt=0.35∟1400 Fmin=2.4dB. The noise figure circle of F=2.4dB will have

12.To compare the relative stability between transistors we require
Stability circles

a)µ test
b)k-Δ test
c)K test

13.The maximum unilateral gain of a transistor is a function of
a)S-parameters of the transistor
c)Source reflection coefficient
d)Both source and load reflection coefficient

#### Module 3

1.In two port oscillator, the required conditon for oscillation
is

a)|Γin |< 1 and |Γout) | < 1 b)Γin |> 1 and |Γout) | < 1 c)Γin |> 1 and |Γout) | > 1
d)|Γin |< 0 and |Γout) | < 0

2.Which of the following device is suitable for one port
oscillator design

a)transistor
b)Gunn diode
c)FET
d)UJT

3.The Compressed Smith chart is useful for
a)Oscillator design
b)Amplifier Design
c)Mixer design
d)Attenuator design

4.Which of the following is the good property of generator tunning
network?

a)It should dissipate large amount of power
b)It should store large energy as compare to energy dissipated
c)It should store small energy
d)It should use negative resistance device

5.How instability can created in case of oscillator design
a)Giving a negative feedback
b)Giving a positive feedback
c)Using a tank circuit
d)Using a capacitors

6.Is it possible to use normal Smith chart for reading input
impedance for reflection coefficient greater than one?

a)Possible
b)Not possible
c)Only possible for certain values of reflection coefficient
d)Possible if magnitude of reflection coeffcient is greater than 5

7.In two port oscillator design, if the input impedance is -24-
j1.9 Ω, then the terminating impedance required to create
enough sustanable oscillation –

a)-24-j1.9 Ω
b)24
c)8+j1.9 Ω
d)j1.9 Ω

8.Which of the following is used resonator circuit used to tune
oscillator in microwave frequency range?

a)Yttrium iron garnet (YIG)
b)L and C tank circuit
c)Resistive circuit
d)Gunn diode circuit

9.What is phase noise in microwave oscillator?
a)White noise
b)Noise contributed by the external sources
c)The short-term random fluctuation in the frequency (or
phase) of an oscillator signal
d)1/f noise

10.Conversion loss of mixer is defined as
a)the ratio of available IF output power to the available RF input
power, expressed in dB
b)the ratio of available RF input power to the LO output power,
expressed in dB
c)The ratio of available RF input power to the available IF
output power, expressed in dB
d)the ratio of available LO power to the available IF output
power, expressed in dB

11.Which of the following relation holds true for noise figure of
SSB and DSB signal?

a)noise figure of SSB and DSB signal are equal
b)noise figure of SSB is 3dB more than DSB
c)noise figure of SSB is 0.25 times of DSB
d)noise figure of SSB is 5 times of DSB

12.A balanced mixer using a 900
hybrid provides

a)Good matching characteristics but poor isolation
between RF and LO ports
b)Good matching characteristics and isolation between RF
and LO ports
c)Poor matching characteristics and isolation between RF and
LO ports
d)Poor matching characteristics but good isolation between
RF and LO ports

13.A 3 GHz oscillator is to de designed using negative resistance
diode having reflection coeffcient of 1.25∟450
and Z0=50
ohm, what value of load impedance

a)35.39+j111.22
b)35.39-j111.22
c)35.39
d)0-j111.22

14.Which of the following type of oscillator provide wide
bandwidth?

a)Lumped Element type
b)Distributed transmission line
c)Cavity
d)varactor type

#### Module 4

1.It synthesizes a specified frequency from one or more
reference frequencies from a combination of harmonic
generators, filters, multipliers, dividers, and frequency mixers.

a)direct frequency synthesis
b)direct digital frequency synthesis
c)frequency synthesis by phase lock

2.The main disadvantage of this method are that the
complexity and size are increased, the possibility of
spurious components being introduced by the mixer is
increased, and the phase lag of the filter used in the
feedback path can degrade the loop performance.

a)PLL frequency synthesizer with down conversion
b)Direct frequency synthesis
c)Direct digital frequency synthesis
d)Hybrid frequency synthesizer

3.Direct Frequency synthesis require
a)One or more reference frequencies , mixers, bandpass
filters
b)Bandpass filter
c)Mixers
d)Clock generators

4.The indirect frequency synthesis is achieved using the
a)PLL
b)VCO
c)Loop Filter
d)Feedback divider

5.The element in a PLL that helps to use a wide range of
reference frequencies

a)Reference divider
b)VCO
c)Prescaler
d)Phase detector

6.The points of difference between fractional N PLL and
integer type PLL are

a)The points of difference between fractional N PLL and
integer type PLL are
b)Fractional PLL have high phase noise and more spurious
noise than integer type PLL
c)Fractional PLL have low phase noise and less spurious
noise than integer type PLL
d)Fractional PLL have high phase noise but less spurious
noise than integer type PLL

7.Direct digital frequency synthesis is obtained by solving
digital recursion relationship using a general-purpose
computer or ….

a)Multiple loop indirect synthesis
b)Sorting sine wave values in the lookup table
c)A PLL-DDFS combination
d)Direct frequency synthesis

8.Select the following one which is not a method of
obtaining frequency synthesis.

a)Direct frequency synthesis
b)Compressed frequency synthesis
c)Frequency synthesis by phase lock loop
d)Frequency synthesis by variable modulus divider

9.What is a frequency synthesizer?

a)Generate low frequency at its output with reference to
reference input frequency.
b)Generate high frequency at its output with reference to
reference input frequency.
c)Generate a single frequency at its output with reference to
reference input frequency.
d)Generate a large number of frequencies at its output
with reference to refence input frequency.

#### Module 5

1.Which source has highest contribution of noise when
dealing with low noise receivers using high gain
antennas UHF and VHF antenna?

a)Extraterrestrial source
b)Terrestrial source
c)Arc welding source
d)Electric traction

2.In radiation from an Electromagnetic pulse, which rays
are most active

a)Alpha rays
b)gamma rays
c)beta rays
d)Zeta rays

3.The crosstalk is characterized by –

a)EM noise developed by thermal agitation of electrons
b)Coupling of EM noise from one conductor to another
c)Signal interferences between two channels
d)Ground potential interference

4.The transient produced on the power transmission line is
an example of –

a)Crosstalk between the conductors
c)EM noise produced in the apparatus
d)EM noise contributed by the device nonlinearities

5.Cable harnessing refers to –
a)Specific manufacturing process of power cables and other
cables
b)Impedance measurement of given cable
c)Assembling different cables together in a single
package
d)Cable cutting techniques

6.In a transformer-based system, the differential mode
interference from the primary to the secondary side
occurs via –

a)Electric field coupling
b)Only magnetic field coupling
c)Both electric and magnetic coupling
d)Convection mechanism

7.Which of the following is not the effect of EMI?
a)Interference to radio and television reception
b)Loss of digital and analog data which is transmitted by
the transmitter.
c)Reduced the waveguide dimensions.
d)Delay in the system output.

8.Delay in the system output.
a)Analog and digital
c)Byte and word
d)Current and voltage

9.Select the following one option which is not part of reducing

a)Use of shield over cables
b)Conventional grounding of PCBs and cabinet.
c)Sustaining the separation between cables of different signal levels
d)Increase the channel capacity.

10.Which of the following is not a part of the natural source of
EMI?

a)Cosmic noise
b)Automobile ignition
c)Lighting discharge
d)Electric storms

11.Which of the following is not a part of the human made source
of EMI?

a))Automobile ignition
b)Electric storms
c)Oscillators
d)Motors

12.Any conductor carrying electrical current has an associate
with….

a)Resistive field
b)Electric field
c)Magnetic field
d)Capacitive field

13.Shielding is ……… to avoid unwanted noise from relating
with a susceptible piece of equipment.

a)dBµV/m/MHz
b)dBµA
c)dBµV/MHz
d)dBA/m

a)dBµV/m/MHz
b)dBµA
c)dBµV/MHz
d)dBA/m

#### Module 5

1.Electrostatic discharge originates due to:

a)Electromagnetic pulse
b)Separation of static charges
d)Attraction of static charges

2.The ability of an electronic system to function properly in
its intended electromagnetic environment and should not be
a source of pollution to that electromagnetic environment is
known as:

a)Susceptibility
b)Emission
c)Electromagnetic interference
d)Electromagnetic compatibility

3.Receptor is a component or device that:
a)Receives noise or interference from the source.
b)Produces the emission
c)Transfers the emission energy
d)Provides a low resistance path between electrical or
electronic equipment

4.___________ is a technique that reduces or prevents
coupling of undesired radiated electromagnetic energy into
equipment to enable it to operator compatibly in its
electromagnetic environment.

a)Bonding
b)Filtering
c)Shielding
d)Grounding

5.In EMC signal, the source delivers maximum power to the
input of transmission line when the transmission line input
impedance

a)Is equal to the source resistance
b)Greater than the source resistance
c)Smaller than the source resistance
d)Is equal to the load resistance

6.________ is not a EMC Standard
a)CISPR
b)MIL-STD 461 D
c)VDE
d)FDM

7.The following is not the EMI effect triggered due to
improper electrical bonding –

b)Intermodulation products development in the circuits
c)Development of unnecessary potential differences
d)Development of unnecessary resonance effects in the
circuits

8.For the shielding operations the following two mechanisms
are absolutely responsible –

b)Absorption loss and reflection loss
c)Dielectric loss and attenuation loss
d)Ohmic and dielectric loss

9.The best grounding system suitable for computer system
consisting peripheral units is –

a)Hybrid ground with high frequency isolation system
b)Multi point grounding
c)Single point grounding
d)Floating ground

10.The impedance coupling interference generated by means of –
a)Radiation interference caused between two conductor
systems
b)Conductive coupling caused between the two devices
c)Cable harnessing
d)Finite non-zero value of ground impedance

11.The 62% location distance is finalized as perfect resistance
measurement for the 3 electrode method because –

a)At this location the voltage if found to be maximum
b)At this location the current is found to be zero
c)At this location the variation in the resistance is found
to be negligible
d)At this location the average voltage is found

12.In the four-electrode method of ground resistance
measurement, a power supply of high frequency is used
because

a)Use of high frequency supply improves the isolation
b)Use of high frequency supply reduces the surface
resistance
c)Use of high frequency supply provides removal of leakage
resistance
d)Use of high frequency supply avoids polarization effects
and avoids straw current errors in the soil