Description : The noise output of a resistor is amplified by a noiseless amplifier having a gain of 60 and a bandwidth of 20 kHz. A meter connected at the output of the amplifier reads 1mV RMS. If the bandwidth of the amplifier is reduced to ... does the meter read now? A. 0.5 mV B. 0.5 µV C. 5.0 mV D. 5.0 µV
Last Answer : A. 0.5 mV
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 : An amplifier operating over the frequency range of 455 to 460 kHz has a 200 kΩ input resistor. What is the RMS noise voltage at the input to this amplifier if the ambient temperature is 17˚C ? A. 40 µV B. 4.0 µV C. 400 µV
Last Answer : B. 4.0 µV
Description : The square of the thermal noise voltage generated by a resistor is proportional to A. its resistance B. its temperature C. the bandwidth over which it is measured D. All of the above
Last Answer : D. All of the above
Description : Indicate the false statement A. The noise generated in a resistance or the resistive component of any impedance is random. B. Random noise power is proportional to the bandwidth over which is measured ... exist D. All formula referring to random noise are applicable only to the value of such noise.
Last Answer : C. A random voltage across the resistor does not exist
Description : What is the noise voltage across a 300Ω input resistance to a TV set with a 6MHz bandwidth and temperature of 30˚C? A. 2.3 µV B. 3.8µV C. 5.5µV D. 5.4µV
Last Answer : C. 5.5µV
Description : Two resistors, 20kΩ, and 50kΩ are at ambient temperature. Calculate for a bandwidth equal to 100kHz, the thermal noise voltage for the two resistors connected in parallel. A. 0.4782µV B. 4278 µV C. 4.78 µV D. 47.8 µV
Last Answer : C. 4.78 µV
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 : The value of the resistor creating thermal noise is doubled. The noise power generated is therefore. A. halved B. quadrupled C. doubled D. unchanged
Last Answer : D. unchanged
Description : The radiation patterns of earth coverage antennas have a beamwidth of approxiamately A. 21˚ B. 5˚ C. 17˚ D. 35˚
Last Answer : C. 17˚
Description : Indicate the false statement. A. HF mixer are generally noisier than HF amplifiers. B. Impulse noise voltage is dependent on bandwidth C. Thermal noise is independent of the frequency at which is measured. D. Industrial noise is usually of the impulse type.
Last Answer : B. Impulse noise voltage is dependent on bandwidth
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 : The voltage induced across a certain coil is 200 mV. A 1200 resistor is connected to the coil terminals. The induced current will be: A. 1.7 mA B. 16 mA C. 12 mA D. 120 mA
Last Answer : The voltage induced across a certain coil is 200 mV. A 1200 resistor is connected to the coil terminals. The induced current will be: 1.7 mA
Description : if noise voltage =120 mv and signal voltage = 80 v , S/N ratio in dB is?
Last Answer : Answers is the place to go to get the answers you need and to ask the questions you want
Description : Which of the following is not a way of minimizing if not eliminating noise? A. Use redundancy B. Increase transmitted power C. Reduce signaling rate D. Increase channel bandwidth
Last Answer : D. Increase channel bandwidth
Description : The total noise power present in a 1-Hz bandwidth . A. Noise density B. Noise figure C. Noise limit D. Noise intensity
Last Answer : A. Noise density
Description : Noise can be reduced by A. widening the bandwidth B. narrowing the bandwidth C. increasing temperature D. increasing transistor current levels
Last Answer : B. narrowing the bandwidth
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 : What bandwidth is needed to support a capacity of 128 kbps when the signal power to noise power ratio in decibels is 100? A. 19224 Hz B. 3853 Hz C. 19244 Hz D. 3583 Hz
Last Answer : B. 3853 Hz
Description : Emission on a frequency or frequencies immediately outside the necessary bandwidth which result from the modulation process except spurious emission. A. Radiation B. Noise C. Out of the band D. Interference
Last Answer : C. Out of the band
Description : Which does not effect noise in a channel? A. None of these B. Bandwidth C. Temperature D. Quantizing level
Last Answer : D. Quantizing level
Description : The ratio of the level of the modulated output of a transmitter under conditions of standard test modulation to the level of the demodulated output with no modulation applied both measured with the ... . Reference audio output B. None of these C. Audio frequency response D. Residual noise level
Last Answer : D. Residual noise level
Last Answer : The noise generated by a resistor depends upon its operating temperature.
Description : Where is the noise generated that primarily determines the signal-to-noise ratio in a VHF (150MHz) marine-band receiver? A. Man-made noise B. In the atmosphere C. In the receiver front end D. In the ionosphere
Last Answer : C. In the receiver front end
Description : Where is the noise generated that primarily determines the signal-to-noise ratio in a VHF (150 MHz) marine-band receiver? A. In the ionosphere B. In the receiver rear end C. In the receiver front end D. In the atmosphere
Description : An amplifier without feedback has a voltage gain of 50, input resistance 1kΩ and output resistance of 2.5kΩ. The input resistance of the current-shunt negative feedback amplifier using the above amplifier with a feedback factor of 0.2 would be: (1) 1/11 kΩ (2) 1/5 kΩ (3) 5 kΩ (4) 11 kΩ
Last Answer : An amplifier without feedback has a voltage gain of 50, input resistance 1kΩ and output resistance of 2.5kΩ. The input resistance of the current-shunt negative feedback amplifier using the above amplifier with a feedback factor of 0.2 would be: 1/11 kΩ
Description : A piezo-electric type pressure sensor has a sensitivity of 1 mV/kPa and a bandwidth of 300 Hz to 300 kHz. For a constant (dc) pressure of 100 kPa, the steady state output of the sensor in millivolt is (A) 0 (B) 2 (C) 4 (D) 6
Last Answer : A piezo-electric type pressure sensor has a sensitivity of 1 mV/kPa and a bandwidth of 300 Hz to 300 kHz. For a constant (dc) pressure of 100 kPa, the steady state output of the sensor in millivolt is 0
Description : An emf of the order of mV is generated when two solutions of different hydrogen ion concentration are separated by a thin glass wall". This is the working principle of a (A) pH meter (B) Polarimeter (C) Chromatograph (D) Polarograph
Last Answer : (A) pH meter
Description : With regard to pattern electroretinogram: a. it can be used to estimate the visual acuity b. it is generated by the occipital cortex c. it is reduced in optic nerve diseases d. the signal amplitude is about 10 mV
Last Answer : it is reduced in optic nerve diseases
Description : Children under the age of 5 can hear up to___________. a)25 Hz b)25 kHz c)20 Hz d)20kHz
Last Answer : b)25 kHz
Description : ___________ is device that measures the internal open circuit voltage of an equivalent noise generator having an impedance of 600Ω and delivering noise power to a 600 Ω load. A. Psophometer B. Barometer C. Reflectometer D. Voltmeter
Last Answer : A. Psophometer
Description : One of the following is not a useful quantity for comparing the noise performance receivers. A. Input noise voltage B. Equivalent noise resistance C. Noise temperature D. Noise figure.
Last Answer : A. Input noise voltage
Description : Which of the following is not a source of industrial noise? A. Automobile ignition B. Sun C. Electric Motors D. Leakage from high voltage line
Last Answer : B. Sun
Description : The most common unit of noise measurement in white noise voltage testing. A. NPR B. dBm C. dBW D. dBrn
Last Answer : A. NPR
Description : The main benefit of light-wave communications over microwaves or any other communications media is a. Lower cost b. Better security c. Wider bandwidth d. Freedom from interference
Last Answer : c. Wider bandwidth
Description : What is antenna bandwidth? A. Antenna length divided by the number of elements B. The angle between the half-power radiation points C. The angle formed between two imaginary lines drawn through D. The frequency range over which an antenna can be expected to operate satisfactorily
Last Answer : D. The frequency range over which an antenna can be expected to operate satisfactorily
Description : Ho w many times bigger does the bandwidth of a fiber optic multimode have over a cable? A. 50 times bigger B. 100 times bigger C. 10 times bigger D. 5 times bigger
Last Answer : B. 100 times bigger
Description : What is meant by the term antenna bandwidth A. Antenna length divided by the number of elements. B. The angle between the half-power radiation points C. The frequency range over which and antenna ... perform well D. The angle formed between two imaginary line drawn through the ends of the elements
Last Answer : C. The frequency range over which and antenna can be expected to perform well
Description : What is the primary advantage of DSBSC in AM? A. Reduce bandwidth over standard AM B. All of these C. It is simpler to transmit and receive than the standard AM D. No transmitter power is wasted in the carrier
Last Answer : D. No transmitter power is wasted in the carrier
Description : Full scale Ammeter reading is 10 mA, Voltage across Ammeter is 100 mV. Then for 100 A measurements the power loss in the circuit is a) 1 W b) 10 W c) 100 W d) 1000 W
Last Answer : Ans: 10 W*
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 : Which of the following contributes to the broadening of laser emission bandwidth? a. Doppler shift of moving atoms and molecules b. Amplification within the laser medium c. Coherence of the laser light d. Optical pumping of the laser transition
Last Answer : a. Doppler shift of moving atoms and molecules
Description : Is the width of the range of wavelengths emitted by the light source a. Bandwidth b. Chromatic Dispersion c. Spectral width d. Beamwidth
Last Answer : c. Spectral width
Description : The bandwidth of optical fiber a. 900MHz b. 900PHz c. 900THz d. 900EHz
Last Answer : c. 900THz
Description : What happens to the bandwidth of an antenna as it is shortened through the use of loading coils? A. It is increased B. It is decreased C. No change occurs D. It becomes flat
Last Answer : A. It is increased
Description : _____ is the amount of uncertainty in a system of symbols A. Bandwidth B. Enthalpy C. Entropy D. Quantum
Last Answer : C. Entropy
Description : ______ is the measurement of a unilateral antenna properties of directivity A. Phase angle B. Antenna gain C. Beamwidth D. Bandwidth
Last Answer : C. Beamwidth
Description : What is the typical bandwidth of a satellite band? A. 36 MHz B. 40 MHz C. 70 MHz D. 500 MHz
Last Answer : D. 500 MHz
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 bandwidth of C-band satellite frequency band in U.S. A. 500 GHz B. 1000 GHz C. 1000 MHz D. 500 MHz