Instrumentation Engineering
GATE IN concept:frequency PYQs
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How to practice concept:frequency
Attempt a question, record the concept and assumptions, then check the available answer. Rework mistakes after revising the relevant concepts. Topic tags can overlap; review the question context.
Questions 1–10 of 17. Imported answers require independent review unless marked reviewed.
Question 48
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A closed Lissajous pattern observed on an oscilloscope in the X – Y mode has three horizontal tangencies and two vertical tangencies in steady state. If the signal-frequency on channel-X is 600 Hz, then the signal-frequency on channel-Y is ________ Hz.
Your answerChoose one option.
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In the phase-locked-loop circuit shown below, the output of the VCO is a digital square wave.
If the input is a square wave at 10 kHz, the steady state frequency of the output is ______ kHz. (rounded off to the nearest integer)
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A digital counter increments its count every 0.1 μs. The counter is used in an instrument to measure frequency. The counter is operated for one period of the input signal to the instrument to measure its frequency. The input signal is approximately at 100 kHz. The maximum error in the measured frequency is _____ kHz. (rounded off to the nearest integer)
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You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answerQuestion 48
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Consider an ultrasonic measurement system shown in the figure. The ultrasonic transmitter (T) sends a continuous wave signal
volts towards an object whose vibration is modeled as
volts. Neglecting the phase shift due to any other effect, the received signal at the receiver (R) is
volts.Assuming the frequency sensitivity factor as 500 Hz/volt,
kHz,
kHz, the modulation index (
) and the frequency deviation in
, respectively, are 
Your answerChoose one option.
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You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answerQuestion 61
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In the diagram shown, the frequency of the sinusoidal source voltage
is 50 Hz. The load voltage is 230 V (RMS), and the load impedance is
. The value of attenuator
. The multiplier output voltage
, where
and
are the inputs. The magnitude of the average value of the multiplier output
is __________ V (rounded off to one decimal place).
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You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answerQuestion 16
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A sinusoidal carrier wave with amplitude
and frequency
is amplitude modulated with a message signal
having frequency
to generate the modulated wave
given by
The message signal that can be retrieved completely using envelope detection is ______Your answerChoose one option.
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You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answerQuestion 22
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In which of the following bridge(s) is the balancing condition frequency-independent?
Your answerSelect all correct options. You can choose more than one.
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You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answerQuestion 32
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A 10½ digit Counter-timer is set in the ‘frequency mode’ of operation (with
s). For a specific input, the reading obtained is 1000. Without disconnecting this input, the Counter-timer is changed to operate in the ‘Period mode’ and the range selected is microseconds (
s, with
MHz). The counter will then displayYour answerChoose one option.
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You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answerQuestion 50
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A 3½ digit, rectifier type digital meter is set to read in its 2000 V range. A symmetrical square wave of frequency 50 Hz and amplitude ±100 V is measured using the meter. The meter will read _____.
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You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answerQuestion 22
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A sinusoid of 10 kHz is sampled at 15 k samples/s. The resulting signal is passed through an ideal low pass filter (LPF) with cut-off frequency of 25 kHz. The maximum frequency component at the output of the LPF (in kHz) is ____.
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