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An opt optic fibe fiberr wit with 3.2 3.2 µm diam diamet eteer core ore was was used used for for communication; the core and cladding indexes for refraction are 1.59 and and 1.51 1.51,, resp respec ecti tive vely ly.. Calc Calcul ulat atee the the cuto cutoff ff wave wavele lengt ngth h on micrometer.
Perc Comms 1
POC Problem Set Noise and AM
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Calculate the image frequency for a standard AM receiver (IF=455 kHz) and tuned to 540 kHz.
Ans. 1450 kHz
Ans. 1.27
What is the noise voltage of a parallel combination resistors on a 1 MHz frequency range?
Determ Determine ine the optica opticall power power in microw microwatt attss 60 km from from a 0.1 milliwatt source on a single mode fiber that has 0.25 dB/km loss.
Ans. 2.31 microvolts
Ans. 3.165
Calcu Calculat latee the percen percentag tagee of maximu maximum m coupli coupli coupling if the loop coupler for a magnetic field is ro to the field.
Calculate the power driven to the speaker of a radio receiver, if the antenna receives 8 microvolts signal into its 5 0 ohm input impedance.
Ans. 50%
Ans. -119 dBW Calculate the optical power in microvolts at a distance 60 km from a 0.1 milliwatt milliwattss source, source, on a single mode fiber that has a 0.25 dB/km loss.
Calculate the image frequency for a standard AM b receiver in the Philippines tuned to 540 kHz.
Ans. 1450 kHz
Ans. 3.165
What power in watts is required of an 8 level cod necessary for a binary code?
A digita digitall transm transmiss ission ion system system has a BER of 10,000 10,000 and is 100 milliwatts bits long. Calculate the expected number of error.
Ans. 392
Ans. 10,000
In cellular system with frequency reuse of 7, for a to channels, calculate the radio capacity.
Calculate the noise bandwidth of a tuned circuit whose dynamic resistance is 1.4 kΩ, while the capacitance is 20 pF.
Ans. 171
Ans. 8.9 MHz
A radar mile is the time required for a radar pulse to to an object and return to the receiver. One radar equivalent to how many microseconds?
*Crosstalk in telephony, refers to the unwanted coupling between signal paths and contribute the crosstalk coupling loss in dBx core unit of crosst crosstalk alk in dB above reference coupling coupling if the crosstalk crosstalk coupling is 20 dBx.
Ans. 70 Determine the excess noise ratio (ENR) in dB of a device if the temperature is 990 K.
Ans. 12.36
In an SSB communication system, what is the maxim of the unwanted sideband, if the duration from a p phase shift is 6 degrees? degrees?
Ans. 25.6 dB
Ans. 3.8 In optical communication system, calculate the dispersion factor in ns/km if the maximum data rate for a length of 10 km is 1.33 Mbps.
Calculate the approximate tower separation in fee operat operating ing on 950 kHz antenn antennaa are separa separated ted degrees.
Ans. 15
Ans. 345
A radio transmitter radiates 100 W power when 100% modulated. How much power is saved when the carrier and one sideband is suppressed?
The front-to-back ratio for an antenna with a forwa and the reverse gain of -2dB is
Ans. 17 dB
Ans. 83 W The maximu maximum m value value that that a chara characte cteris ristic tic impeda impedance nce of an air dielectric parallel parallel wire could have is ___ ohms.
Determine the transient time in cycles, that electrons space, for a practice reflex klystron microwave oscil used is 2?
Ans. 83
Ans. 2.75
Using a uniformly illuminated parabolic reflector, calculate the half power beamwidth for an antenna antenna with a gain gain of 40 dB.
*Calculate the power in a 1 millisecond pulse of the e by one photon for infrared light energy at (Planck’s constant is equal to 6.68 * 10^-34 J-s).
Ans. 1.4 degrees
Ans. 1.22 x 10^-16 *Calculate the antenna power gain for beamwidth of 10 degrees.
Ans. 26 dB In digi digita tall modu modula lati tion on syst system em,, what what is the the inpu inputt rate rate to MSK MSK modulator, if the mark frequency is 5 MHz. Assume n is equal to unity.
In radar system set up by the police to tract speed vio the lowest value of radar pulse repetition frequency ( used used to ensure ensure that the first first blind speed is abo wavelength used is 15 cm).
Ans. 10 Mbps
Sign up to vote on this title Ans. 733 kHz Useful Not useful
Calculate the absorption in metric sabine contributed by 30 persons inside a room.
A communication receiver has a 1 MHz bandwidth a figure. If a signal-to-noise ratio of 10 dB is desired the sensitivity?
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Ans. 70.38 degrees
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Medium 1 is made of glass, while medium 2 is made of ethyl alcohol. Their refractive indexes are 1.45 and 1.34 respectively. For an angle of incidence of 37 degrees, determine the angle of refraction.
Ans. 40.63 degrees
Perc Comms 1
POC Problem Set Noise and AM
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δ = 50 kHz fm = 5 kHz BW = ?
Ans. 110 kHz
What is the effective radiated power (ERP) of a repeater with 200 W transmitting power output, 2 dB duplexer loss, 2 dB feed line loss, 3 dB circulator loss, and feed line antenna gain of 10 dB?
A = 42,241.0979 P = 0.9972 H=? α = AP^2/3 h = α – 6370
Ans. 398 W
Ans. 591,437,697.7
For an Ethernet bus that is
Peak visual transmitter power = 5 kW Peak aural transmitter power = ?
An amplifier NF = 3 dB Determine Teq
Ans. 20% 5 kW
Ans. 288.5 K
11th octave above 1 Hz
Ans. 2048 Hz 3 stage amplifier Stage 1 Power gain 10 Noise 2 Calculate NF
stage 2 20 4
stage 3 30 5
λ=? Rin = 10 cm TE11 Kr = 1084
Ans. 0.034 m
Ans. 2.37 3 stage amplifier Teq ≤ 70 K Gt ≥ 45 dB Stage 1 NF(max) = ? Power gain
N = ? Unclad fiber Diameter core = λ light used n = 1.55 stage 2 3 dB 20 dB
stage 3 6 dB 15 dB
Ans. 6
An amplifier has a noise figure of 4 dB. If the signal-to-noise ratio of its input is 30 dB, what is the signal-to-noise ratio at its output in dB?
*Rectangular waveguide W = 0.8 m H = 0.6 m F = 12 GHz λ=?
Ans. 26
Ans. 4.06 cm
Ans. 0.56
Find the modulation index of a 20 V carrier is amplitude modulated of inclination You're Reading aDegree Preview by three different frequencies with amplitudes 1 V, 2 V, and 3 V U = 35790 km respectively. R = 6378 km Unlock full access withAns. a free trial. Ans. 0.187 1.94º In an SSBSC system, what will be the value of the maximum Download instantaneous peak power if the peak envelope power (PEP) is 6 watts?
λ of 4th harmonic of a 1 meter long radio wave
With Free Trial Ans. 0.25
Ans. 12 W
*Ncore = 1.54, nclad = 1.5 NA = ?
A phase modulation system operates with a modulation index of 1.2. What is the maximum phase shift in degrees?
Ans. 0.352
Ans. 69 Solution:
Semiconductor diode E = 1.9 eV, f = ?
1.2rad ×
180°
rad
π
Frequency 10 octaves above 30 Hz
Ans. 3 Formula: 2
n
=
f 2 f 1
Reliability = 99.999%
Ans. 459 THz *Given: 400 ft antenna at f = 6200 kHz λ=?
Ans. 0.488
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Length of antenna = 3.5λ, fo = 5 MHz L = ? Useful Not useful
Ans. 295.2 ft
Determine λ in Angstrom of the light frequency 322
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POC Problem Set Noise and AM
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Ans. 55
*Determine bandwidth efficiency of a 16 QAM mod Mbps input.
*A microwave communications uses plane reflectors as passive repeaters. The diameter of the parabolic antenna is 18 ft., while the effective area is 310 ft^2. Determine the reflector coupling factor.
Ans. 4 Mbps
Ans. 0.906 as encoded
Ans. 54 dB
*What is the characteristics impedance of a basic parallel wire line if its diameter is 0.023 in with spacing of 0.4 in apart, if it uses a dielectric material made of continuous polyvinyl chloride?
Vmax = 2.6 V, Vmin = 0.29, determine percent mod
Ans. 234 ohms
Given pulse spreading constant = 10 ns/m and cable Determine maximum bit rate in Mbps for UPNRZ tra
What would be the MPD of a 50 year old man?
Ans. 0.5 Mbps
What is the dynamic range for 10 bit sign magnitude
Ans. 11.15%
Ans. 160 rems R = 20,000 ohms, T = 290 K, calculate the noise threshold voltage BW = 100 kHz
*Determine the resolution for 8 bit linear PCM decoded voltage 1.27 Vp.
Ans. 0.005
Ans. 5.65 μV Frequency swing of FM modulation = 80%. Parallel combination, R = 10 kΩ,C = 0.5 μF. Calculate the effective noise bandwidth.
Ans. 129 kHz
Ans. 50 Hz
Pc = 10 W, m = 90%, total transmitted power = ?
Ans. 4.05 W Noise factor of 10, determine the noise figure.
Ans. 10
Input signal of 1.5 MHz is mixed with local oscillat filter selects an IF, the output is ___
Sample rate of 30 kHz in PCM, determine the maximum analog input frequency.
Ans. 3.5 MHz
Ans. 15 kHz
An AM current reads 8 A with an unmodulated ca modulation, what is antenna current?
Speed of sound is 1000 ft/s, what frequency has a wavelength of 24 in?
Ans. 9.38 A
Ans. 500 Hz
In satellite communications, total transmit pow determine energy per bit, transmission rate = 30 Mbp
Average power = 500 W, 4 ohm loudspeaker, determine RMS current.
Ans. -40 dBW
Ans. 11 A
Earth station transmitter with output power = 10 kW 3 dB, branching loss = 4 dB, gain = 40 dB, determine
Plate voltage = 2000 V, plate current = 500 mA, modulated 50%. 73 dBW You're Reading aAns. Preview Determine audio power. Equivalent noise bandwidth 10 MHz (satellite system Ans. 125 W Unlock full access with0.0280 a free pW, trial.determine noise density in dBW. Find audio power, modulated 65%, dc power output is 1 kW. Ans. -205.5 dBW
Ans. 201 W
Download With Free Trial Half-wave antenna
Audio power = 500 W, modulated 50%. Find RC power input.
radiates transceiver operat Determine physical length.
Ans. 4000 W
Ans. 66.9 ft
5 kW antenna, field intensity of 50 μV/m in receiver what 20 kW produce?
G = 10 dB, Pt = 6000 W, determine ERP
Ans. 6000 W
Ans. 100 μV/m If antenna current increased 3 dB times, radiated power increase
Determine bandwidth efficiency for QPSK modu Mbps.
Ans. 11.56 times
Ans. 2 bits/cycle
*Antenna current increases 2.8 times, field strength increase
For 16 QAM
Ans. 2.8
Ans. 4 bits/cycle
Two towers of 1000 kHz separated by 128. What is the tower separation in ft?
input bit For BPSK modulation with fc = 80m MHz, Sign up to vote on this title determine minimum Nyquist bandwidth.
Ans. 328 ft
Ans. 10 Useful MHz
Not useful
*Voltage in antenna = 2.7 V, field intensity in the antenna site is 27 mV/m. What is the effective height?
For QPSK, fc = 70 MHz, fc = 10 Mbps, determine m bandwidth.
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POC Problem Set Noise and AM
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Channel capacity for signal power of 200 W, noise power of 10 W, and bandwidth of 2 kHz.
Frequency deviation = 5 kHz, fm = 500 Hz, (S/N calculate (S/N)output.
Ans. 8815 bps
Ans. 40 dB
Calculate the peak power in a 120 mV NRZ square wave on a 600 ohm channel.
Phase modulation system, modulation index = 1.2, w phase shift?
Ans. 12 µV
Ans. 69 degrees
Binary data is to be transmitted at 10 kbps, what minimum bandwidth to pass the fastest information change undistorted?
Fc = 220 MHz, m = 3, fm = 2 kHz, what is bandwidt rule?
Ans. 5 kHz
Ans. 16 kHz
Aspect ratio, 6 MHz NTSC TV
Ethernet bus, 500 meters length, velocity communication rate = 10 Mbps, calculate total nu each station before collision, both stations transmit.
Ans. 1.33 How long does it take to scan 2 picture elements when 400 are scanned in 60 µs?
Ans. 25 bits
Ans. 0.3 µs
Asynchronous communication system uses ASCII a light bit, 1 start bit, 0 parity bit, and 1 st words/minute (assume word has 5 char/letter and 1 sp
Calculate the time of one horizontal line for frames operated at 25 Hz with 62.5 interlaced lines/frame of a TV receiver.
Ans. 9600 words/min
Ans. 64 µs Attenuator loss = 26 dB, power applied = 3 W, Po = 500 candle power that is located 12 ft from a surface provides how many lux?
Ans. 7.54 mW
Ans. 37.57
An amplifier with 20 dB gain is connected to another by means of a transmission line with a loss of 4 dB, power level of -14 dBm were applied to the syste power output.
Signal power at input to an amplifier is 100, noise power is 1 µW. At the output, signal power is 1 W noise power is 90 mW. Noise figure =?
Ans. 12 dBm
Ans. 6 dB Transistor has power dissipation of 30 W, calculate the power an amplifier could deliver to the load if it operates in class A, efficiency is 30%.
Ans. 12.80 W
An amplifier with an overall gain of 20 dB is impres whose power level is 1 watt. Calculate the power out
Ans. 50
A signal in a cable TV system has an amplitude of 4 resistance line. Calculate its level in d Bm.
Telephone system local loop has resistance of 1 kohm and telephone Ans. -36.7 connected off hook resistance is 200 ohms. Calculate voltage when You're Reading a Preview phone is off hook. A 300 ohm resistor is connected across the 300 ohm a TV receiver. The bandwidth of the receiver is at Ans. 8 V Unlock full access withnoise a free trial. applied to the receiver input. voltage A tone measures 80 dBrnc at the output of a 4 wire central office. Ans. 2.73 µV What will it be at a local loop that is -8 dB TLP? Download With Free Trial A diode generator is required to produce 12 µV of no Ans. 74 dBrnc with an input impedance of 75 ohms and a noise po *Frequency which 400 Hz baseband frequency will be translated for Determine the current through the diode in mA. channel 7 of a group o f FDM system Ans. 400
Ans. 83.6 kHz Carrier frequency = 150 MHz Modulating frequency = 3 kHz Em = 30 V Find peak voltage of the lower side frequency/ upper side frequency.
Ans. 15 V Transmitter supplies 10 kW of carrier power. Rload = 50 ohms, fc = 1.2 MHz, m = 0.85, fm = 3 MHz. Calculate rms voltage.
Ans. 825 V Kf = 30 MHz/V, fc = 175 MHz, Em = 4 V, determine frequency deviation.
R1 and R2 connected in series at 300 K and 900 ohms, R2 = 300 ohms, find P at the load bandwidth = 100 kHz.
Ans. 0.496 fW
*Receiver produces noise power of 250 mW with output increases to 5 W when the signal is applied, c in dB.
Ans. 13
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What is the cut off frequency of a rectangular wave width of 0.6 in and a height 0.36 in? Useful Notofuseful
Ans. 9842.5 MHz
Ans. 169.8 kHz How often will hand offs occur when a veh
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Perc Comms 1
POC Problem Set Noise and AM
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the choir members singing with the same intensity. What is the difference in the sound intensity level in two cases?
Ans. 10,240 Hz
Ans. 13 dB
In radar communications system, calculate the ra meters for a target, if the time between the transmissi of the signal is 167 reception.
*A sound pressure (RMS) of 125 microbars is equivalent to what pressure level?
Ans. 25,050
Ans. 116 dB *A telephone signal takes 2 quarters of a second to reach is destination… Calculate the via net loss necessary for an acceptable echo.
Ans. 100.4 dB
Calculate the frequency swing of an FM broadcast t modulated 60%.
Ans. 90 kHz
Step index, n-core = 1.35, Δ = 0.03 Determine dispersion/km
Local multipoint distribution service is a two way br that allow communication providers to offer bandwidth services to have and business including br access. LMDS operates at ___ frequency range.
Ans. 159.8 ns/km
Ans. 27 – 31 GHz
Dcore = 50 µm, wavelength = 0.82 µm, NA = 0.343 Determine V number
Find the electric field intensity of a 1 kW broadcast distance of 20 km from the source.
Ans. 64.6
Ans. 8.66 mV/m
A simple mode fiber is made with dcore = 10 µm and is coupled to a light source with a wavelength 2 µm. Its core glass has n = 1.55, determine the clad required for producing single mode propagation, VCO = 2.045
Calculate the actual deviation of an FM audio signa percentage modulation is 72%.
Ans. 1.547
*Transmitter is using a doubler, 2 triplers, and quad its crystal oscillator frequency.
Pw = 1.0 µs, PRR = 900, average plate power input = 45 W, peak power = ?
Ans. 2000 MHz
Ans. 50 kW If acceptance acceptance = 20 degrees, NA = ?
A radio transmitter has to operate at a temperatur signal is derived from a crystal oscillator with tempe of 1 ppm/°C, find the transmitting frequency.
Ans. 34
Ans. 150.0021 MHz
FO cable loss = 16 dB/km, if l = 200 ft, determine attenuator.
Ans. 9.76 dB
An AM transmitter is modulated by two sine wave 2.5kHz with modulation of 20% and 80% respective effective modulation index.
Surface index = 1.55, refractive index = 1.51, determine NA.
Ans. 82%
Ans. 0.305
Ans. 18 kHz
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An AM signal has the following characteristics Glass refractive index 1.56 clad with another glass refractive index Carrier frequency = 150 MHz Unlock full access withModulating a free trial.frequency = 3 MHz 1.51 determine the acceptance angle. Peak carrier voltage = 40 V and peak modulation vol Ans. 17.7 degrees Calculate the peak voltage of the lower sideband and Download With Free Trial Carrier frequency of 6 GHz and a distance 40 km, determine FSL. Ans. 15 V
Ans. 140 dB In a microwave communications, determine the noise power in dBm, 1.4 dBm for noise bandwidth of 10 MHz.
Ans. 104 dBm
A telephone line has a bandwidth of 3.2 kHz and a ratio of 36 dB a signal is transmitted down the line code. Calculate the maximum theoretical data taking present of noise.
Ans. 38.4 kbps (C/N)min = 22 dBm with 10 MHz bandwidth. Determine minimum received carrier power.
Range of 9 dB. Calculate the number of quantizing b
Ans. -82 dBm
Ans. 16
3 amplifiers cascaded, NF = 3 dB, G = 10 dBm, determine Nft
Ans. 5.00 dB
A broadcast TV channel in the Philippines has a MHz. Calculate the minimum permissible S/N in d code.
Transmitter 600 ft, height receive antenna 240 ft, find transmission distance.
Ans. 18 dB Sign up to vote on this title
Ans. 56.5 miles
*Calculate the maximum data rat useful Useful Nottheoretical transponder used for binary data transmission.
Calculate electric field intensity in mV/m at 30 kW from 5 km source
Ans. 72 Mbps
Ans. 12.9
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POC Problem Set Noise and AM
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100 km distant. Assume the antennas are positioned for optimum transmission and reception (gain is 1.64 and effective length is equal to λ/π).
A satellite transmission with 8 W power repeater antenna gain of 40 dB. The receiver 40,000 km awa gain of 50 dBi. If the overall loss is 9 dB, find the ER
Ans. 2.23 µV
Ans. 41 dBW
If a unit mobile radio system the base station transmits 100 V at 160 MHz frequency using half wave dipole antenna 20 m at a receiving antenna at a height of 4 m and distance of 30 km.
Ans. 41.7 µV What would be the maximum range for tropospheric transmission whose antenna heights are 30 m and 20 m?
Ans. 41 km *The drum diameter of fax machine is 70 mm and the scanning pitch is 0.25 mm/s. Calculate the index of cooperation as per IEEE definition.
Ans. 880 The sound pressure level of 0 dB is equivalent to how many microbars?
Ans. 0.002 *Determine the voltage reflection of a 300 ohms line terminated in a load impedance of 100 + j300.
Ans. 0.52/_87° KHz tone is present in channel 4 of group are of a supergroup in FDM communications. Determine at what frequency does the tone appear in the supergroup output.
Ans. 326 kHz Calculate the equivalent the noise bandwidth for a single RC low pass filter of R = 10 k and C = 0.1 µF.
Ans. 250 Hz When the measuring a voice channel at a -4 dB test point level, the meter reads 76 dBm. Calculate the reading in dBrncO.
Ans. 18
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Calculate the transmitted data stream for the following data and CRC Unlock full access with a free trial. generating polynomials.
Ans. 1011011101001
Download With Free Trial
Determine the hamming bit for ASCII character (1011001). Insert the hamming bit using odd parity.
Ans. 01110110001 *Rectangular waveguide used for microwave transmission has a width of 1.4 in and height of 0.8 in. All signal above ___ GHz will passed by the waveguide.
Ans. 4.218 *Calculate the minimum length of a pair of inductors to be considered as a transmission line, if its operating frequency is 800 MHz.
Ans. 37.5 mm Calculate the velocity factor of coaxial cable used as a transmission line, with a characteristic impedance of a 50 ohm, capacitance is 40 pF/m, and inductance is 50 µH/m.
Ans. 0.073 *The input current in a matched transmission line is 50 mA while the
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