Communication Electronics N4 — Document
April 2020 — N4 — Communication Electronics
N4
2020
Nated Engineering
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Q1— Section header —
1.10\ in the ANSWER BOOK.
1.1The current that flows away from the junction is equal to the current entering the same junction
1.2Thevenin theorem states that a two terminal network consisting of impedances and generators can be replaced by a single equivalent voltage generator and series impedance.
1.3In an inductive network the current lags the voltage by 90
1.4An ideal filter has a shar p cut off frequency in its pass band and zero attenuation in the attenuation band.
1.5A ladder type attenuator uses only fixed resistors
1.6he time c onstant of RC ircuits is a period required for a voltage of a capacitor to increase to 63,2% of maximum value or decrease to 36,8% of minimum value.
1.7depth modulation distortion is produced by over modulation.
1.8Oscillator modulation is one of the methods used in modulation.
1.9The an tenna of an AM transmitter is omnidirectional.
1.10The a ngle of reflection is the angle that lies between the reflected ray and the norm to the surface of reflection. (10 [10]10
Q2— Section header —
1.10\ in the ANSWER BOOK.
2.1theorem states that a linear circuit containing independent sources, dependent sources and passive elements can be replaced by a model containing a current source and an equi valent resistance. Thevenin
2.2Any physical quantity that possesses both magnitude and direction Polar coordinates Notation Complex n umbers Phasors
2.3
2.4he term is not used in conjunction with filters. attenuation band cut off frequency resonance frequency pass band
2.5filter are made of a material that when subjected to mechanical strain, the mechanical energy expended is converted to electrical energy. Derived Ceramic Composite
2.6hrough t modulation process the frequency of a carrier is made to vary in accordance with the instantaneous value of the modulating signal. frequency phase amplitude pulse
2.7The type of AM transmission whereby the carrier wave is completely suppressed and at the receiving end the receiver accepts the side band, and the carrier wave generated locally has to be supplied to the demodulator:
2.8The amplifier of the AM t ransmitter amplifies the signal from the microphone to the suitable frequency before it enters the modulator. buffer music power speech
2.9
2.10The widely used non resonant antenna array for point point radio wave propagation Rhombic Pyramidal Sectoral Helical
Q3— Section header —
3.1Define the following:
3.1.2
3.2Use the Norton theorem to find the equivalent ci rcuit of the network in the FIGURE below (6\ [10] FIGURE10
Q4— Section header —
4.1Inductive reactance
4.2Capacitive reactance
4.3Total impedance
4.4Total supply current
4.5Phase angle
4.6Voltage across the inductor
4.7factor
4.8Prove the answer to
Q4— Section header —
Q5— Section header —
5.1Define an attenuator (2\
5.2Make a neat, labelled d raw ing of an type attenuator (1\
5.3Make a neat, labelled d raw ing of the circuit diagram of a low pass filter (1\
5.4Which filter saves space and is light in weight (1\ [5]5
Q6— Section header —
6.1Pulse position modulation
6.2Pulse amplitude modulation
6.36
Q7— Section header —
7.1Draw a full y labelled circuit diagram of an AM full wave detector. (3\
7.2Explain the operation of the circuit diagram mentioned
Q7— Section header —
Q8— Section header —
8.1Draw a block diagram of an AM uper heterodyne receiver.
8.2Explain the function of each stage of the diagram of the receiver mentioned in
Q8— Section header —
Q9— Section header —
9.1Determine the length of a standard half wave dipole antenna used to receive a 60 MHz radio signal. Assume that the velocity of the electromagnetic wave in the antenna is 3 m/s (3\
9.2What is meant by vertical polarisation with regard to ant ennae? (2\
9.3Describe the term ionosphere as applicable to radio wave propagation (2\
9.4Show by means of a sketch the possible ionosphere layers during the day as well as at night . Give a brief description. (5\
9.5Define ritical angle as applicable to radio wave propagation (2\
9.6Make a neat, labelled sketch of each of the following antennae
9.6.218
Topics Identified
2
Business EnvironmentsBusiness Plan
Mark Allocation
Total100 marks
Sections10 + 10 + 10 + 16 + 5 + 6 + 10 + 15 + 18 = 100 marks
Paper information
TitleDocument
SubjectCommunication Electronics
LevelN4
Document typeQuestion paper
Year2020
MonthApril
Pages7
Downloads4
Examination context
Decade2020s
Years ago6y
SeasonAutumn (SH)
Start dayWednesday
Exam periodApril 2020
Days since exam2,383
About Communication Electronics examination preparation
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