Description : Stacking antenna elements A. increases sensitivity to weak signals B. will suppress odd harmonics C. decrease signal to noise ratio D. increases selectivity
Last Answer : A. increases sensitivity to weak signals
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 : The random and unpredictable electric signal from natural causes, both internal and external to the system is know as ________. A. Distortion B. Noise C. Attenuation D. Interference
Last Answer : B. Noise
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 : What is the effect in over modulated amplitude modulated radio broadcasting transmission? A. Interference to adjacent channel B. Higher fidelity C. Increase noise D. Higher audio signal
Last Answer : A. Interference to adjacent channel
Description : _________ is the random and unpredictable electric signals from natural causes, both internal and external to the system. A. Interference B. Attenuation C. Distortion D. Noise
Last Answer : D. Noise
Description : How does spatial isolation technique in satellite communications avoid interference? A. Use of different polarity antennas B. Use of different types of antennas C. Employment of highly directional spot-beam antennas D. Use of low gain antennas
Last Answer : C. Employment of highly directional spot-beam antennas
Description : Noise consisting of irregular pulses of short duration and relatively high amplitude, A. Quantizing noise B. Tone interference C. Impulse noise D. Cross talk
Last Answer : C. Impulse noise
Last Answer : A. Quantizing noise
Description : Deemphasis in the receiver in effect attenuates modulating signal components and noise in what frequency range? A. dc B. low C. intermediate D. high
Last Answer : D. high
Description : What satellite system parameter represents the quality of a satellite or an earth station receiver? A. Gain-to-Equivalent Noise Temperature Ratio (G/Te) B. Energy of Bit-to-Noise Density Ratio (Eb/No) C. Carrier-to-Noise Density Ratio (C/No) D. Bit energy
Last Answer : A. Gain-to-Equivalent Noise Temperature Ratio (G/Te)
Description : Which causes a quantization noise in PCM system? A. Serial transmission errors B. The approximation of the quantized signal C. The synchronization between encoder and decoder D. Binary coding techniques
Last Answer : B. The approximation of the quantized signal
Last Answer : The approximation of the quantized signal
Description : Strong interference from one particular station can be eliminated by the use of A. noise limiters B. squelch circuits C. negative feedback D. wave traps in the antenna circuitry
Last Answer : D. wave traps in the antenna circuitry
Description : Noise that occurs via capacitive or inductive coupling in a cable. A. Crosstalk B. Quantizing noise C. Reference noise D. Tone interference
Last Answer : A. Crosstalk
Description : Form of interference caused by rain or dust storms. A. Precipitation static B. Shot-noise C. Galactic noise D. Impulse noise
Last Answer : A. Precipitation static
Description : nif stands for A. Non-intrinsic figure B. Noise improvement factor C. Narrow intermediate frequency D. Noise interference figure
Last Answer : B. Noise improvement factor
Description : The band of frequencies least susceptible to atmospheric noise and interference is: A. 30 – 300 kHz B. 300 – 3000 kHz C. 3 – 30 MHz D. 300 – 3000 MHz
Last Answer : D. 300 – 3000 MHz
Description : Nif stands for A. Narrow intermediate frequency B. Noise interference figure C. Noise improvement factor D. Non-intrinsic fugure
Last Answer : C. Noise improvement factor
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 : 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 : Three identical circuits having 10 dB signal noise-to-noise ratio each are connected in tandem with each other, what is the overall S/N? A. 5.23 dB B. 14.77dB C. 30 dB D. 40 dB
Last Answer : A. 5.23 dB
Description : What signal-to-noise ratio is required for satisfactory television reception? A. 10 dB B. 30 dB C. 40 dB D. 20 dB
Last Answer : C. 40 dB
Description : What is the quantization signal-to-noise ratio if an 8-bit PCM code is used? A. 40 dB B. 50 dB C. 60 dB D. 65 dB
Last Answer : B. 50 dB
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 : What is meant by the term modulation index? A. The processor index. B. The ratio between the deviation of a frequency modulated signal and the modulating frequency. C. The FM signal-to-noise ratio. D. The ratio of the maximum carrier frequency deviation to the highest audio modulating frequency.
Last Answer : B. The ratio between the deviation of a frequency modulated signal and the modulating frequency.
Description : The signal to noise ratio that is required for a satisfactory television reception. A. 30 dB B. 40 dB C. 10 dB D. 20 dB
Last Answer : B. 40 dB
Description : What signal-to-noise ratio is required for satisfactory telephone services? A. 50 dB B. 30 dB C. 40dB D. 20 dB
Last Answer : A. 50 dB
Description : The signal in a channel is measured to be 23 dB while noise in the same channel is measured to be 9 dB. The signal to noise ratio therefore is __________. A. 9/23 B. 23/9 C. 32 dB D. 14 dB
Last Answer : D. 14 dB
Description : Comparing the signal strength arriving at the driven element from the desired direction to the signal strength reaching the driver from the opposite direction. A. Directivity B. Sensitivity C. Beamwidth D. Front-to-back ratio
Last Answer : D. Front-to-back ratio
Description : What is caused by the transverse nature of electromagnetic waves? A. Polarization B. Interference C. Beamwidth D. Gain
Last Answer : A. Polarization
Description : What is meant by antenna gain? A. The final amplifier gain minus the transmission line losses (including any phasing lines present) B. The ratio of the amount of power produced by the antenna ... D. The numeric ratio relating the radiated signal strength of an antenna to that of another antenna
Last Answer : D. The numeric ratio relating the radiated signal strength of an antenna to that of another antenna
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 : A superhet receiver has an IF of 455 kHz and is experiencing image-channel interference on a frequency of 1570 kHz. The receiver is tuned to A. 1115 kHz B. 660 kHz C. 2025 kHz D. 910 kHz
Last Answer : B. 660 kHz
Description : Why does adding dc vice ac bias voltage to the input signal result in a poor signal-to-noise ratio (SNR)?
Last Answer : With dc bias, the SNR is poor because only a small portion of the magnetism curve is straight enough to use, thus the output signal is weak compared with the natural tape hiss.
Description : How can intermodulation interference between two transmitters in close proximity reduced or eliminated? A. Through installing a band-pass filter in the antenna feed line B. Through installing terminated circulator ... high driving power D. By installing a low-pass filter in the antenna feed line
Last Answer : A. Through installing a band-pass filter in the antenna feed line
Description : Companding helps in reducing __________ with respect to signal: (A) Interference (B) Signal overloading (C) Non linearity (D) Quantization noise
Last Answer : (D) Quantization noise
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 : 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 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 noise figure of the first circuit in tandem connection is 10.5 dB while its power gain is 15, what is the over all noise figure if the second circuit has a noise figure of 11 dB? A. 11.59 dB B. 11.23 dB C. 10.79 dB D. 10.5 dB
Last Answer : C. 10.79 dB
Description : In cellular system, _____ defines the geographic distance that is required between cells using identical frequencies in order to avoid interference between the radio transmissions at these cells. A. frequency-reuse ratio B. distance-to-reuse ratio (D/R) C. reuse format plan ratio D. reuse factor
Last Answer : B. distance-to-reuse ratio (D/R)
Description : Noise occurring in the presence of signal resulting from a mismatch between the exact value of an analog signal and the closet available quantizing step in a digital coder. A. Quantizing noise B. Thermal noise C. Impulse noise D. Crosstalk
Description : What is the reliable measurement for comparing amplifier noise characteristics? A. Thermal agitation noise B. Noise factor C. Noise margin D. Signal-to-noise
Last Answer : B. Noise factor
Description : Unwanted radio signal on assigned frequency. A. Splatter B. RFI C. Noise D. EMI
Last Answer : C. Noise
Description : Noise always affects the signal in a communications systems at the ________. A. transmitter B. channel C. information source D. destination
Last Answer : B. channel
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 : The difference between the original and reconstructed signal gives rise to A. S factor B. Quantizing noise C. S/N D. Fade margin
Last Answer : B. Quantizing noise
Description : Quantization noise is caused by A. binary coding techniques B. serial transmission errors C. the synchronization between encoder and decoder D. the approximation of the quantized signal
Last Answer : D. the approximation of the quantized signal