Mtk Ispit Test 2
Questions and Answers
- 1.
Koja od sledecih modulacija obezbedjuje cetiri bita po simbolu:
- A.
16QAM
- B.
64QAM
- C.
QPSK
- D.
8-PSK
Correct Answer
A. 16QAMExplanation
16QAM provides four bits per symbol because it uses a combination of 16 different amplitude and phase levels to represent each symbol. Each of these levels can represent a unique combination of four bits, allowing for a higher data rate compared to other modulation schemes listed.Rate this question:
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- 2.
Fazorski dijagram prikazan na slici odgovara:
- A.
8 PSK modulaciji
- B.
4 PSK modulaciji
- C.
2 PSK modulaciji
Correct Answer
A. 8 PSK modulacijiExplanation
The given Fazorski diagram corresponds to 8 PSK modulation.Rate this question:
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- 3.
Za uniformno raspodeljen signal u granicama od -Xmax do +Xmax, koristi se uniformni kvantizer sa N=2n nivoa rekonstrucije. Ako se korak kvantizacije smanji dva puta, srednja kvadratna greska (MSE) se:
Correct Answer
Smanji 4 puta,smanji cetiri puta,smanji 4 puta,SMANJI 4 PUTA,SMANJI CETIRI PUTAExplanation
When the quantization step is reduced by two times, the mean square error (MSE) is reduced by four times. This is because a smaller quantization step allows for a more accurate representation of the signal, resulting in less quantization error. The MSE is a measure of the average squared difference between the original signal and the quantized signal, so reducing the quantization step will lead to a decrease in the MSE by a factor of four.Rate this question:
- 4.
Osnovni princip koji se koristi kod diferencijalne impulsno kodne modulacije je:
- A.
Postojanje korelacije izmedju odbiraka koji se koduju
- B.
Korelacija izmedju odbiraka koji se koduju ne postoji
- C.
Postojanje korelacije izmedju nivoa koji se kvantizuju
Correct Answer
A. Postojanje korelacije izmedju odbiraka koji se kodujuExplanation
The correct answer is "postojanje korelacije između odbiraka koji se koduju" (existence of correlation between the samples being encoded). In differential pulse code modulation (DPCM), the difference between consecutive samples is encoded instead of the actual sample values. This encoding scheme takes advantage of the correlation between adjacent samples, as the difference between them tends to be smaller than the actual sample values. By encoding the differences, DPCM can achieve higher compression ratios while maintaining good audio or image quality.Rate this question:
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- 5.
Koriscenjem kompresora i ekspandora kod postupka kvantizacije govora se:
- A.
Smanjuje sum kvantzacije
- B.
Povecava binarni protok
- C.
Povecava ucestanost odabiranja
Correct Answer
A. Smanjuje sum kvantzacijeExplanation
By using a compressor and expander in the speech quantization process, the quantization noise is reduced. The compressor reduces the dynamic range of the speech signal, allowing for a more efficient quantization. The expander then expands the signal back to its original dynamic range, reducing the quantization noise that was introduced during the compression stage. This overall reduction in quantization noise improves the quality of the quantized speech signal.Rate this question:
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- 6.
Koriscenjem komresora i ekspandora kod postupka kvantiacije:
- A.
Ostvaruje se neuniformna kvantizacija
- B.
Ostvaruje se ravnomerna kvantizacija
- C.
Izbegava se potreba za kvantizacijom
Correct Answer
A. Ostvaruje se neuniformna kvantizacijaExplanation
By using a compressor and expander in the quantization process, non-uniform quantization is achieved. This means that the step size or the intervals between quantization levels are not equal throughout the range of values being quantized. This allows for a more efficient allocation of bits, as the quantization levels can be closer together in regions where the signal is more likely to occur, and further apart in regions where the signal is less likely to occur. This can result in improved signal-to-noise ratio and better overall performance in certain applications.Rate this question:
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- 7.
Sta se koristi da bi se umanjila distorzija signala nastala usled propagacije po vise putanja?
- A.
Ekvalizacija
- B.
Pojacavaci
- C.
Uniformna kvantizacija
Correct Answer
A. EkvalizacijaExplanation
Ekvalizacija se koristi da bi se umanjila distorzija signala nastala usled propagacije po više putanja. Ova tehnika se primenjuje kako bi se ispravile promene u frekvencijskom odzivu signala koje su nastale usled različitih putanja kojima signal prolazi pre nego što stigne do prijemnika. Ekvalizacija omogućava poboljšanje kvaliteta signala tako što kompenzuje ove promene i smanjuje distorziju, čime se postiže bolje prenošenje informacija.Rate this question:
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- 8.
Najveci stepen kompresije signala govora se dobija primenom postupaka:
- A.
Linearno prediktivnog kodovanja
- B.
Diferencijalno impulsno kodne modulacije
- C.
Frekvencijski zavisnog kodovanja
Correct Answer
A. Linearno prediktivnog kodovanjaExplanation
Linear predictive coding (LPC) is a technique used in speech signal compression. It works by analyzing the speech signal and predicting future samples based on past samples. By encoding the prediction error instead of the original signal, LPC can achieve high compression ratios while maintaining good speech quality. This makes it an effective method for speech compression, hence it provides the highest degree of compression for speech signals.Rate this question:
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- 9.
Ekvalizacijom se:
- A.
Umanjuje intersimbolska interferencija
- B.
Povecava intersimbolska interferencija
- C.
Poboljsavaju preformanse sistema u uslovima fedinga
Correct Answer
A. Umanjuje intersimbolska interferencijaExplanation
Ekvalizacija refers to the process of equalizing or balancing the signal in a communication system. In this context, it is stated that it reduces intersymbol interference. Intersymbol interference occurs when the symbols in a digital signal interfere with each other, causing errors in the received signal. By applying equalization techniques, such as filtering or equalizer algorithms, the effects of intersymbol interference can be minimized, resulting in improved performance of the system. Therefore, the correct answer is that ekvalizacija umanjuje intersimbolska interferencija.Rate this question:
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- 10.
Adaptivna kvantizacija se koristi zato sto:
- A.
Se menjaju karakteristike prenosnog kanala u vremenu
- B.
Se menjaju osobine signala govora koji se prenosi
- C.
Se menjaju koraci kvantizacije
Correct Answer
A. Se menjaju karakteristike prenosnog kanala u vremenuExplanation
Adaptive quantization is used because the characteristics of the transmission channel change over time. This means that the quality of the signal being transmitted can vary, and using adaptive quantization allows for adjusting the quantization steps to better match the changing channel conditions. By adapting the quantization, it is possible to maintain a more consistent and optimal signal quality throughout the transmission process.Rate this question:
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- 11.
Prostorni prijemni diverziti se koristi da bi se:
- A.
Povecao odnos signal-sum u uslovima ravnog fedinga
- B.
Smanjilo kasnjenje
- C.
Umanjila intersimbolska interferencija
Correct Answer
A. Povecao odnos signal-sum u uslovima ravnog fedingaExplanation
Prostorni prijemni diverziti se koristi da bi se povećao odnos signal-sum u uslovima ravnog fedinga. To znači da se ovom tehnikom želi poboljšati kvalitet prijema signala tako što se povećava snaga korisnog signala u odnosu na šum koji ga prati. Ovo je posebno korisno u uslovima ravnog fedinga gde je signal oslabljen i praćen šumom. Korišćenjem prostornog prijemnog diverziteta, moguće je povećati snagu signala i smanjiti efekat šuma, što rezultira boljim prijemom signala.Rate this question:
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- 12.
Kako se salje informacija u slucaju frekvencijskog diverzitija?
- A.
Informacija se salje na vise nosioca koji su dovoljno razmaknuti
- B.
Informaciju je nemoguce poslati
- C.
Informacija se prenosi u vremenskim intervalima razmaknuti koherentnim vremenskim intervalom
Correct Answer
A. Informacija se salje na vise nosioca koji su dovoljno razmaknutiExplanation
In the case of frequency diversity, information is sent on multiple carriers that are sufficiently spaced apart. This technique helps to improve the reliability and robustness of the transmission by spreading the information across different frequencies. By using multiple carriers, any interference or fading affecting one carrier may not affect the others, thus increasing the chances of successful transmission.Rate this question:
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- 13.
Upotreba interlivera:
- A.
Povecava kasnjenje
- B.
Povecava binarni protok
- C.
Smanjuje binarni protok
Correct Answer
A. Povecava kasnjenjeExplanation
The correct answer is "povecava kasnjenje" which means "increases delay" in English. This suggests that the use of interleave increases the delay in a certain process or system.Rate this question:
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- 14.
Upotreba interlivera se koristi:
- A.
Da bismo od paketskih greski napravili slucajne greske
- B.
Da bismo smanjili intersimbolsku interferenciju
- C.
Da bismo smanjili kasnjenje u dekodovanju signala
Correct Answer
A. Da bismo od paketskih greski napravili slucajne greskeExplanation
The correct answer is "da bismo od paketskih greski napravili slucajne greske" (to introduce random errors from packet errors). This suggests that the use of interleave is intended to intentionally introduce random errors into the data stream in order to improve error correction capabilities and increase the reliability of the transmission. By rearranging the order of the data packets, errors are spread out and can be more effectively detected and corrected.Rate this question:
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- 15.
Sve kodne reci jednog linearnog blok koda su (00000, 01110, 10011, 11101) odrediti maksimalni broj gresaka koje moze detektovati ovaj kod:
- A.
2
- B.
3
- C.
0
Correct Answer
A. 2Explanation
The given linear block code has codewords (00000, 01110, 10011, 11101). To determine the maximum number of errors that this code can detect, we need to find the minimum Hamming distance between any two codewords. The Hamming distance is the number of positions at which the corresponding bits are different.
By comparing all pairs of codewords, we find that the minimum Hamming distance is 2. For example, the Hamming distance between codewords 00000 and 01110 is 2. Therefore, this code can detect up to 2 errors.Rate this question:
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- 16.
Sve kodne reci jednog linearnog blok koda (00000, 01110, 10011, 11101) odrediti minimalno Hemingovo rastojanje:
- A.
3
- B.
2
- C.
4
Correct Answer
A. 3Explanation
The given linear block code consists of four codewords: 00000, 01110, 10011, and 11101. To determine the minimum Hamming distance, we need to find the smallest number of bit positions in which any two codewords differ. By comparing each pair of codewords, we can see that the minimum Hamming distance is 3 because there are three bit positions (1st, 2nd, and 4th) where any two codewords differ.Rate this question:
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- 17.
Kako se menja binarni protok primenom linearnog blok koda?
- A.
Povecava se
- B.
Smanjuje se
- C.
Ne menja se
Correct Answer
A. Povecava seExplanation
By applying linear block code to binary protocol, the efficiency of the protocol increases. This means that the amount of data that can be transmitted within a given time frame or bandwidth is increased. Linear block codes are error-correcting codes that add redundancy to the transmitted data, allowing for the detection and correction of errors. By reducing the probability of errors in the transmitted data, the overall performance and reliability of the binary protocol are improved, leading to an increase in its effectiveness.Rate this question:
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- 18.
Jedan od najpoznatijih blok kodova je:
- A.
Hemingov kod
- B.
Viterbijev kod
- C.
Ciklicni kod
Correct Answer
A. Hemingov kodExplanation
The correct answer is "Hemingov kod." Hemingov kod, also known as Hamming code, is one of the most well-known error-detecting and error-correcting codes. It was developed by Richard Hamming in the 1950s and is widely used in computer memory systems and communication networks. This code adds extra bits to the original data to detect and correct errors that may occur during transmission or storage. By comparing the received data with the transmitted data, Hamming code can identify and correct single-bit errors and detect multiple-bit errors.Rate this question:
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- 19.
Pojednostavljena blok sema telekomunikacionog sistema sadrzi sledece blokove: izvor, korisnik, zastitni koder, zastitni dekoder, modulator, demodulator i kanal. Isprevan redosled blokova je:Odvajati sa razmakom, ne koristiti zapetu(zarez)! Sve malim slovima pisati!
Correct Answer
izvor zastitni koder modulator kanal demodulator zastitni dekoder korisnikExplanation
The correct answer is the given order of the blocks: izvor zastitni koder modulator kanal demodulator zastitni dekoder korisnik.Rate this question:
- 20.
Kako se menja BER u sistemu koristeci zastitno kodovanje?
Correct Answer
BER opada,BER OPADAExplanation
The use of error protection coding in a system helps to decrease the Bit Error Rate (BER). By implementing error protection coding techniques, such as forward error correction (FEC) or error detection and retransmission, the system can detect and correct errors that occur during transmission. This ultimately leads to a decrease in the BER, improving the overall reliability and quality of the system.Rate this question:
- 21.
GSM koristi sledecu metodu visestrukog pristupa:
- A.
FDMA/TDMA
- B.
Samo FDMA
- C.
Samo TDMA
Correct Answer
A. FDMA/TDMAExplanation
GSM (Global System for Mobile Communications) uses a combination of FDMA (Frequency Division Multiple Access) and TDMA (Time Division Multiple Access) for multiple access. FDMA allows different users to share the available frequency spectrum by dividing it into multiple channels, each assigned to a specific user. TDMA further divides each FDMA channel into time slots, allowing multiple users to share the same frequency simultaneously by assigning them different time slots. This combination of FDMA and TDMA enables efficient utilization of the available frequency spectrum, allowing multiple users to access the network simultaneously.Rate this question:
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- 22.
Razmak izmedju nosioca u GSM sistemu je:
- A.
200kHz
- B.
100kHz
- C.
1MHz
Correct Answer
A. 200kHzExplanation
The correct answer is 200kHz. In the GSM system, the frequency division multiple access (FDMA) technique is used to divide the available frequency spectrum into multiple channels. Each channel, also known as a carrier, has a bandwidth of 200kHz. This allows multiple users to simultaneously access the network without interfering with each other's signals.Rate this question:
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- 23.
Maksimalna brzina prenosa podataka u GSM-u je:
- A.
9,6kbit/s
- B.
9,3kbit/s
- C.
9,5kbit/s
Correct Answer
A. 9,6kbit/sExplanation
The correct answer is 9,6kbit/s. In GSM (Global System for Mobile Communications), the maximum data transfer rate is 9.6 kilobits per second. This refers to the maximum speed at which data can be transmitted over a GSM network.Rate this question:
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- 24.
Bitska brzina u jednom radio kanalu u GSM-u je:
- A.
270kbit/s
- B.
270TDMA/s
- C.
156,25kbit/s
Correct Answer
A. 270kbit/sExplanation
The correct answer is 270kbit/s. This is the bit rate in one radio channel in GSM. GSM (Global System for Mobile Communications) is a standard for mobile communication that uses TDMA (Time Division Multiple Access) technology. The bit rate refers to the number of bits that can be transmitted per second. In this case, it is 270kbit/s, meaning that 270,000 bits can be transmitted in one second in this radio channel.Rate this question:
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- 25.
U GSM sistemu se koristi:
- A.
FDD (Frekvencijski dupleks - Frequency division duplexing)
- B.
TDD (Vremenski dupleks - Time division duplexing)
- C.
I FDD i TDD
Correct Answer
A. FDD (Frekvencijski dupleks - Frequency division duplexing)Explanation
In the GSM system, the technique used is FDD (Frequency Division Duplexing). This technique allows for simultaneous transmission and reception of signals on different frequencies. It divides the available frequency band into two separate channels, one for uplink (from mobile to base station) and one for downlink (from base station to mobile). By using different frequencies for uplink and downlink, FDD ensures that there is no interference between the two directions of communication. This enables efficient and reliable communication in the GSM system.Rate this question:
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- 26.
U GSM sistemu svaki od radio kanala je podeljen na:
- A.
8 TDMA kanala
- B.
4 TDMA kanala
- C.
16 TDMA kanala
Correct Answer
A. 8 TDMA kanalaExplanation
In the GSM system, each radio channel is divided into 8 TDMA channels. TDMA stands for Time Division Multiple Access, which is a technique used to divide a single radio channel into multiple time slots, allowing multiple users to share the same frequency. By dividing the radio channel into 8 TDMA channels, more users can be accommodated within the same frequency band, increasing the overall capacity and efficiency of the system.Rate this question:
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- 27.
U GSM sistemu fizicki kanal predstavlja (u toku koga 1 korisnik emituje podatke):
- A.
1 vremenski interval na 1 nosiocu
- B.
1 vremenski interval na svim nosiocma
- C.
Uredjeni niz bita koji se salje u toku jednog vremenskog slota
Correct Answer
A. 1 vremenski interval na 1 nosiocuExplanation
In the GSM system, a physical channel represents one time slot on one carrier. This means that during one time interval, one user transmits data on one carrier frequency.Rate this question:
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- 28.
U GSM sistemu se preko fizickih kanala prenose:
- A.
I saobracajni i signalizacioni signali
- B.
Samo saobracajni signali
- C.
Samo signalizacioni signali
Correct Answer
A. I saobracajni i signalizacioni signaliExplanation
In the GSM system, both traffic and signaling signals are transmitted over physical channels. This means that not only the actual communication between users (traffic signals) is carried over these channels, but also the necessary control and coordination signals (signaling signals) that are required for the proper functioning of the system. These signaling signals are used for tasks such as call setup, handover, and network management. Therefore, in the GSM system, both traffic and signaling signals are transmitted over the physical channels.Rate this question:
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- 29.
Niz uredjenih bita koji se prenose u jednom intervalu (slotu) i koji se naziva burst je:
- A.
Razlicit za razlicite logicke kanale
- B.
Uvek iste strukture
- C.
Razlicite strukture, ali uve nosi saobracajne podatke
Correct Answer
A. Razlicit za razlicite logicke kanaleExplanation
The burst, which is a set of ordered bits transmitted in one interval (slot), is different for different logical channels. This means that each logical channel has its own unique burst structure.Rate this question:
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- 30.
Koju modulaciju koristi GSM sistem?
- A.
GMSK
- B.
TDMA
- C.
FDMA
Correct Answer
A. GMSKExplanation
GSM system uses GMSK modulation. GMSK stands for Gaussian Minimum Shift Keying, which is a form of frequency modulation. It is used in GSM systems to efficiently transmit data by shifting the carrier frequency in a way that minimizes interference and improves signal quality. GMSK modulation is particularly suitable for mobile communication systems like GSM due to its ability to provide good spectral efficiency and low power consumption.Rate this question:
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- 31.
Modulator prikazan na slici na izlazu daje
- A.
BPSK modulisani signal
- B.
QPSK modulisani signal
- C.
PSK modulisani signal
Correct Answer
A. BPSK modulisani signalExplanation
The modulator shown in the image on the output gives a BPSK modulated signal.Rate this question:
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