Description : What establishes the receiver bandwidth? A. RF amplifier B. Mixer C. Local oscillator D. IF amplifier
Last Answer : D. IF amplifier
Description : What consists the front-end circuit of a VHF TV superheterodyne receiver? A. Mixer, RF amplifier and AFC? B. RF amplifier, Band pass filter and mixer C. Local oscillator, mixer and RF amplifier D. Local oscillator, AGC and antenna
Last Answer : C. Local oscillator, mixer and RF amplifier
Description : Refers to one of the front end circuit of a VHF TV superheterodyne receiver which is usually a separate circuit coupled to the mixer. A. Antenna feed B. AGC C. RF amplifier D. Local oscillator
Last Answer : D. Local oscillator
Description : One of the following is a high powered RF ac basic transmitter that has two or more stages, the oscillator stage which determines the frequency opereation and RF amplifier stage orstages that develop the ... to develop a good frequency stability. A. Goldsmith B. MOPA C. Alexanderson D. Hartley
Last Answer : B. MOPA
Description : In an FM receiver, which circuit removes amplitude variations? A. Exciter B. Mixer C. Discriminator D. Limiter
Last Answer : D. Limiter
Description : Cross modulation on a receiver is eliminated at the A. RF stage B. mixer stage C. IF stage D. detector stage
Last Answer : D. detector stage
Description : When measuring a transmitter’s frequency against a suitable standard, the frequency to be measured is taken from the A. oscillator stage B. intermediate amplifier C. buffer stage D. final RF stage
Last Answer : D. final RF stage
Description : An FM receiver whose intermediate frequency is 10.7 MHz, is experiencing image channel interference from a station transmitting on 121.1 MHz. If the local oscillator is tracking above, the receiver is tuned to A. 131.8 MHz B. 110.4 MHz C. 142.5 MHz D. 99.7 MHz
Last Answer : D. 99.7 MHz
Description : Referred to as the stage in the radio receiver that contributes most of the noise. A. IF amplifier B. Supply stage C. Speaker D. Mixer
Last Answer : D. Mixer
Description : One of the following is a possible cause of an abrupt frequency variation in a self exited transmitter oscillator circuits resulting to a poor frequency stability to hold a constant frequency ... capacitor in the oscillator D. Loose connections in the oscillator, amplifier, or antenna circuits.
Last Answer : D. Loose connections in the oscillator, amplifier, or antenna circuits.
Description : Which of the following is one of the possible causes for a slow drift of frequency in a self exited transmitter oscillator circuits resulting to a poor frequency stability? A. Poor soldered connections ... , or antenna circuits D. DC and RF heating of resistors, causing then to change values.
Last Answer : D. DC and RF heating of resistors, causing then to change values.
Description : In a triple conversion superheterodyne receiver, diode mixer stages are operated A. In the linear region B. In the nonlinear region C. As class A amplifiers D. As class B amplifiers
Last Answer : B. In the nonlinear region
Description : Calculate the noise figure of the receiver whose RF amplifier has an input resistance of 1000Ω and an equivalent shot-noise resistance of 2000Ω, a gain of 25 and load resistance of 125 kΩ. Given that the bandwidth is 1. ... to an antenna with an impedance of 75Ω. A. 30.3 B. 3.03 C. 303 D. .303
Last Answer : A. 30.3
Description : Which of the following parts of the radio receiver represent the component that extracts the desire RF signal from the electromagnetic wave? A. AF amplifier B. Antenna C. Detector D. Crystal
Last Answer : B. Antenna
Description : What is the local oscillator (mixer) frequency of the satellite with an uplink frequency in GHz band? A. 3500 MHz B. 4500 MHz C. 2225 MHz D. 2555 MHz
Last Answer : C. 2225 MHz
Description : Describe the functions of mixer and local oscillator in radio receiver
Last Answer : Frequency Mixer:- The function of frequency mixer is to heterodyne signal frequency fs and local oscillator frequency fo. At the output, it produces the difference frequency known as ... local oscillator frequency fo is then mixed with incoming frequency to give intermediate frequency.
Description : Which circuit contributes most of the noise in a receiver? A. IF amplifier B. Demodulator C. AF amplifier D. Mixer
Description : The front-end of a television receiver, having a bandwidth of 7Mhz, and operating at a temperature of 27˚C , consists of an amplifier having a gain of 15 followed by a mixer whose gain is 20. The ... equivalent noise resistance for this television receiver. A. 8760 Ω B. 875Ω C. 8.76Ω D. 0.876Ω
Last Answer : B. 875Ω
Description : Which of the following methods cannot be used to increase the bandwidth for cascaded RF amplifier stages? A) Wave traps in each stage B) Stagger tuning C) A shunt damping resistor across each tuned circuit D) Doubled tuned transformers with tighter coupling
Last Answer : A) Wave traps in each stage
Description : Not a reason for the use of an antenna coupler. A. To make the antenna look resistive B. To provide the output amplifier with the correct load impedance C. To discriminate against harmonics D. To prevent re-radiation of the local oscillator
Last Answer : D. To prevent re-radiation of the local oscillator
Description : A particular circuit that rids FM of noise A. Detector B. Discriminator C. Phase Shifter D. Limiter
Description : What particular circuit that rids FM of noise? A. HPF B. Phase shifter C. Limiter D. LPF
Last Answer : C. Limiter
Description : Explain the working of amplitude limiter in FM receiver with circuit diagram.
Last Answer : Amplitude limiter: The function of amplitude limiter is to remove all amplitude variation of FM carrier voltage that may occur due to atmospheric disturbances. Use of amplitude limiter makes the system less noisy Circuit Diagram:
Description : Draw block diagram of FM receiver and explain the use of limiter circuit.
Last Answer : Diagram Explanation Amplitude limiter: The function of amplitude limiter is to remove all amplitude variation of FM carrier voltage that may occur due to atmospheric disturbances. Use of amplitude limiter makes the system less noisy.
Description : When no signal is being received, the loudspeaker is not entirely silent as a result of the presence of A. parasitic oscillations in some of the receiver stages. B. negative feedback in each stage. C. spurious frequencies as a result of improper neutralization. D. internal receiver noise.
Last Answer : D. internal receiver noise.
Description : Type of emission produced by one of the early radio transmitter in trains of damped RF ac waves where its oscillator is coupled to a long wire antenna, normally used in radio telegraph and having sidebands on its carrier. A. Digital emission B. Key emission C. Cycle emission D. Spark emission
Last Answer : D. Spark emission
Description : What part or section of a TV receiver that separates the sound and video signals? A. IF stage B. Video amplifier C. Video detector D. Burst separator
Last Answer : C. Video detector
Description : How can receiver desensitizing be reduced? A. Increase the receiver bandwidth B. Ensure good RF shielding between the transmitter and receiver C. Increase the transmitter audio gain D. Decrease the receiver squelch, gain.
Last Answer : D. Decrease the receiver squelch, gain.
Description : ECE Board Exam March 1996 What is the purpose of the receiver's squelch circuit? A. To overcome fluctuations in the level the RF signal arriving at the receiver antenna B. To prevent ... signals D. To prevent amplified noise from reaching the loudspeaker during the absence of an incoming signal
Last Answer : D. To prevent amplified noise from reaching the loudspeaker during the absence of an incoming signal
Description : One of the FM signal generator control which varies the phase of the modulating voltage applied to the oscillator of the sweep generator A. Band control B. Phase control C. Marker amplitude control D. Sweep output control
Last Answer : B. Phase control
Description : What is the meaning of forward power? A. The power traveling from the transmitter to the antenna. B. The power radiated from the top of an antenna system. C. The power produced during the positive half of an RF cycle. D. The power used to drive a linear amplifier.
Last Answer : A. The power traveling from the transmitter to the antenna.
Description : he local oscillator and mixer are combined in one device because:
Last Answer : it is cheaper
Description : Referred to an oscillator signal “leak through” from a properly neutralized amplifier such as a master oscillator power amplifier. A. Carrier B. Stray signal C. Back wave D. Loss wave
Last Answer : C. Back wave
Description : The final power amplifier in an FM transmitter usually operates class ______. A. AB B. C C. B D. A
Last Answer : B. C
Description : The final amplifier of either FM or AM transmitter operates as A. Class B B. Class C C. Class A D. Class D
Last Answer : B. Class C
Description : What is the local oscillator frequency range commercial AM broadcast if it is equal to 455 KHz. A. 540 to 1600 KHz B. 0 to 1600 KHz C. 995 to 2055 KHz D. 0 to 455 KHz
Last Answer : C. 995 to 2055 KHz
Description : A superheterodyne radio receiver with an IF of 455KHZ is turned to 1000KHZ. Find: (i) Image frequency (ii) Local oscillator frequency
Last Answer : Given Intermediate Frequency fi=455KHz Signal frequency =fs=1000KHz Local oscillator frequency fo=fs+fi Fo=1000KHz+455KHz =1455KHz Image frequency is the input frequency which produces the same intermediate frequency fsi=fs+2fi =1000KHz+2*455KHz =1910KHz
Description : Why should local oscillator frequency be greater than signal frequency in AM receiver? Also explain why IF has constant value?
Last Answer : Reason for LO frequency to be greater than signal frequency The local oscillator frequency (f0) is made greater than signal frequency (Fs) in radio receiver: Local oscillator frequency range is 995 ... frequency of desired signal because the IF is constant and same for all the incoming RF signal.
Description : A super heterodyne AM receiver is tuned to a station operating at 1200 KHz .Find local oscillator frequency and image frequency.
Last Answer : A super heterodyne AM receiver is tuned to a station operating at 1200 KHz Intermediate frequency is 455KHz. IF frequency=f0-fs Local oscillator frequency is f0=IF +fs=455K+1200K=1655kHz The image frequency which gives the same IF is f0+2*IF=2110KHz
Description : Indicate the false statement. Noise figure is defined as A. the ratio of the S/N power supplied at the input terminal of a receiver or amplifier to the S/N power supplied to the output or ... under test, both working at the same temperature over the same bandwidth and fed from the same source
Last Answer : C. an unwanted form of energy tending to interfere with the proper and easy reception and reproduction of wanted signals
Description : What do you call the single booster installed on the antenna dish of satellite receiver? A. Low noise amplifier B. Single amplifier C. Noise amplifier D. Rectifier
Last Answer : A. Low noise amplifier
Description : One ofthe followingis not a reason forthe use of anantenna coupler: a. To make the antenna look resistive b. To provide the output amplifier with the correct load impedance c. To discriminate against harmonics d. To prevent reradiation of the local oscillator
Last Answer : d. To prevent reradiation of the local oscillator
Description : List two types of oscillator, which generates frequency in RF range.
Last Answer : Types of Oscillators generating frequencies in RF range: i) Hartley Oscillator ii) Colpitt’s Oscillator iii) Clapp Oscillator
Description : The first stage of a two-stage amplifier has a voltage gain of 10, a 600 Ω input resistor, a 1600Ω equivalent noise resistance and 27kΩ output resistor. For the second stage, these values are 25, 81kΩ, 19kΩ, and 1MΩ, ... this two stage amplifier. A. 2,518 kΩ B. 2,518 Ω C. 251.8 Ω D. 12,518 Ω
Last Answer : B. 2,518 Ω
Description : Which amplifier stage (the preamplifier or the postamplifier) is a dominant contributor of noise and significantly influences the sensitivity of the receiver?
Last Answer : The preamplifier.
Description : If coil 'R1-R2' on the transmitter in figure 'A' shown in the illustration is turned 30 degrees clockwise, corresponding coil 'R1-R2' on the receiver should ____________. EL-0092 A. make coils 'S1 ... a higher voltage depending on the turns ratio D. align itself to the same position if free to move
Last Answer : Answer: D
Description : Match the stages of meiosis in column I to their characteristic features in column II and select the correct option using the codes given below. Column I Column II A. Pachytene (i) Pairing of homologous chromosomes B. Metaphase I (ii) ... , C-(iii), D-(i) (d) A-(iv), B-(iii), C-(ii), D-(i)
Last Answer : (a) A-(iii), B-(iv), C-(ii), D-(i)
Description : A shunt-fed quarter-wavelength Marconi antenna A. has maximum RF impedance to ground at its feedpoint B. has a current null at its feedpoint C. has a zero DC resistance to ground D. has zero RF resistance to ground
Last Answer : C. has a zero DC resistance to ground
Description : A method of multiple accessing where a given RF channel bandwidth is divided inot smaller frequency band. A. CDMA B. ANIK-D C. TDMA D. FDMA
Last Answer : D. FDMA
Description : The product of the radiated RF power of a transmitter and the gain of the antenna system in a given direction relative to an isotropic radiator is called ____. A. Effective Radiated Power (ERP) B. Effective Isotropic Radiated Power (EIRP) C. Radiated Power D. Transmit Power
Last Answer : B. Effective Isotropic Radiated Power (EIRP)