Racunarske Mreze - Ispit

If an amplifier doubles the input signal, the relationship between the output power and the input power can be represented as +3 dB.

Addressing is necessary in any layer where there are multiple destinations. This means that when there are multiple possible destinations for a packet, addressing is required to determine the correct destination.

The correct answer explains that the application layer allows the application process to access the OSI environment. This means that the application layer provides the necessary protocols and services for applications to communicate with each other over a network. It enables applications to establish connections, exchange data, and perform other network-related functions within the OSI model.

The correct answer is "Слојевита архитектура" which translates to "Layered architecture" in English. This term refers to a design approach in which a system is divided into different layers, each responsible for a specific set of functions. This allows for modular and scalable development, as well as easier maintenance and troubleshooting. In the context of computer networks, layered architecture refers to the organization of protocols and network components into different layers, such as the OSI model.

The quality of signal transmission depends on the quality of the transmission medium and the quality of the signal being transmitted.

The correct answer is "Максимална вредност сигнала" which translates to "Maximum value of the signal" in English. This means that the amplitude of the signal refers to the maximum value that the signal reaches at any given time.

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If the signal is weakened by 0 dB on a certain section and the input power is 1 mW, it means that the power at the output is also equal to 1 mW.

The correct answer is 1/R. This is because the duration of a bit is inversely proportional to the data rate. In other words, as the data rate increases, the duration of each bit decreases. Therefore, the duration of a bit is equal to 1/R, where R is the data rate.

The correct answer is "Захтев, идентификација, одговор, потврда" (Request, identification, response, confirmation). This set represents the primitives of a service. In a service-oriented architecture, these primitives are essential for communication between service providers and consumers. The request is made by the consumer, identification is used to authenticate and authorize the request, the provider sends a response to the request, and finally, the confirmation is sent to acknowledge the successful completion of the request.

The main characteristic of channel switching is that the channel between two stations is occupied for the entire duration of the connection. This means that no other stations can use the channel while the connection is active.

The correct answer states that the layer provides a way to establish, maintain, and terminate a connection. This suggests that the layer is responsible for the process of establishing a connection between two devices, ensuring that the connection remains active, and terminating the connection when necessary. It implies that the layer handles the communication between devices and manages the connection throughout its lifecycle.

In broadcast communication networks, each node only needs one port for communication. This is because in a broadcast network, a single message is sent to all nodes simultaneously, so there is no need for multiple ports for communication. Therefore, the correct answer is 1 порт (1 port).

The correct answer is OSI, TCP/IP, ATM. These three options represent different network architectures. OSI (Open Systems Interconnection) is a conceptual framework that standardizes the functions of a communication system into seven different layers. TCP/IP (Transmission Control Protocol/Internet Protocol) is a set of protocols that allows computers to communicate on the internet. ATM (Asynchronous Transfer Mode) is a network technology that transmits data in fixed-size cells and is used in high-speed networks.

Increasing the data speed increases the probability that the received bit will be incorrect.

If we have three components and each component weakens the signal by 3, 8, and 11 dB respectively, the total weakening is calculated by adding up the individual weakenings. Therefore, the total weakening is 3 + 8 + 11 = 22 dB.

The correct answer is that a unipolar signal means that all signaling elements have the same sign or are zero. In other words, in a unipolar signal, all the elements either have a positive value or a negative value, or they are all zero. This is in contrast to a bipolar signal, where the elements can have both positive and negative values.

The correct answer is "Протоколи са и без успоставе везе" which translates to "Protocols with and without established connection". This answer suggests that there are different types of protocols used in computer networks for data transmission, some of which require establishing a connection before data can be transmitted, while others do not require such a connection.

Impulse noise is a type of noise that is a random, sudden, and short-duration disturbance in a signal. It can be caused by various factors such as electrical interference, faulty equipment, or transmission errors. In digital communications, impulse noise can corrupt the transmitted data and lead to errors in the received signal. Therefore, it is considered as the primary source of errors in digital communications.

The main requirement of a data transmission subsystem is to transmit data without errors.

Increasing the bandwidth allows for an increase in data speed. By increasing the bandwidth, more data can be transmitted simultaneously, resulting in a higher data transfer rate.

The correct answer is "Слој сесије" which translates to "Session layer" in English. The session layer is responsible for establishing, managing, and terminating sessions between applications. It provides services such as session establishment, synchronization, and checkpointing to ensure reliable communication between applications. This layer handles the dialogue control and coordination between the sender and receiver, allowing them to exchange data in an organized and efficient manner.

According to the OSI reference model, if there is a change in one layer, it does not affect the other layers. Each layer operates independently and has its own specific functions and responsibilities. Therefore, any change in one layer will not have an impact on the other layers of the OSI model.

Временска синхронизација укључује подешавање брзина и секвенционирање. Овај процес је битан за координирање и синхронизацију различитих уређаја и система у један уједињени систем. Подешавање брзина се односи на усаглашавање брзина преноса података између различитих уређаја, док секвенционирање се односи на усаглашавање временског тока података и њихово правилно секвенционирање. Овај процес је неопходан за исправан пренос и обраду података.

The correct answer is "Две парњак целине" which means "Two counterparts of a whole." This suggests that the protocol allows data exchange between two counterparts or two entities that are part of a whole system.

The correct answer is "Подлога за дефинисање стандарда за повезивање хетерогених мрежа" which translates to "A basis for defining standards for connecting heterogeneous networks." This answer is correct because the OSI reference model is a conceptual framework that standardizes the functions of a communication system into seven different layers. It provides a common language and structure for different network technologies to communicate and interoperate with each other, regardless of their differences. Therefore, it serves as a foundation for defining standards for connecting heterogeneous networks.

Пarњак целине (PEER) refers to the same layers on different machines. This means that the corresponding layers on different machines are considered as a pair. Therefore, the correct answer is "Исти слојеви на различитим машинама" which translates to "The same layers on different machines".

The correct answer is "Значење које човек додељује подaцима" which translates to "The meaning that a person assigns to data." This answer suggests that the information being referred to is the interpretation or significance that a person gives to data. It implies that data itself is meaningless without human interpretation and understanding.

The correct answer is "Транспортном слоју" (Transport layer). The transport layer is responsible for the end-to-end delivery of data between hosts. It ensures that data is delivered reliably and in the correct order. This layer also handles flow control and error recovery mechanisms.

Thermal noise is a type of noise that is generated due to the random motion of electrons in a conductor caused by temperature. It is a natural and unavoidable phenomenon that cannot be completely eliminated. The higher the temperature, the greater the thermal noise. Therefore, the correct answer is that thermal noise depends on temperature and cannot be eliminated.

According to the OSI model, layer N on one machine communicates with layer N on another machine.

If we want a signal that is attenuated by 13 dB to remain unchanged, we need to amplify it by +13 dB. This means that we need to increase the power of the signal by 13 decibels in order to compensate for the attenuation and restore it to its original level.

If a node is out of function in a datagram network, the packets will be redirected. This means that the packets will be sent to another node or router in the network that can handle the transmission. The out-of-function node will not be able to establish a connection or perform any retransmissions, but the packets will not be lost as they will be directed to another node for further processing.

Модем се koristi za pretvaranje digitalnih signala u analogne signale. Digitalni signali su binarni (0 i 1), dok su analogni signali kontinuirani. Modem prima digitalni signal i pretvara ga u analogni signal koji se može prenositi preko telefonske linije ili drugih analognih kanala.

A signal can be in the function of time because signals can vary over time, and their values can change at different points in time. Time is a crucial parameter in signal processing as it helps in analyzing the behavior and characteristics of the signal at different instances. By studying how a signal changes over time, we can gain insights into its frequency, amplitude, and other properties. Therefore, time is an essential factor in understanding and processing signals.

If a signal with harmonics at 1kHz, 3kHz, and 5kHz is fed into a low-pass filter with a cutoff frequency of 2kHz, only the harmonic at 1kHz will appear at the output. This is because a low-pass filter allows frequencies below the cutoff frequency to pass through while attenuating higher frequencies. Therefore, the harmonics at 3kHz and 5kHz will be filtered out, and only the harmonic at 1kHz will remain.

The correct answer is "Фуријеова трансформација" (Fourier transformation). Fourier transformation is a mathematical discipline that serves as the basis for the concept of frequency domain. It allows us to analyze a signal or function in terms of its frequency components, breaking it down into a sum of sinusoidal functions. This transformation is widely used in various fields, including signal processing, image analysis, and communication systems.

The correct answer is "Растављању сложеног сигнала на простопериодичне компоненте" which translates to "Decomposing a complex signal into periodic components." This explanation states that Furier transformation is used to break down a complex signal into its individual periodic components.

If a node is out of function in a network with virtual circuits, it means that the connection between that node and other nodes is lost. In order to restore the connection, the node needs to establish a new link with other nodes. Therefore, the correct answer is "Поново се успоставља веза" which translates to "The connection is reestablished."

The main role of a protocol is to facilitate the exchange of data between two entities on different systems. Protocols define the rules and procedures for communication, ensuring that data can be transmitted and received accurately and efficiently. In this case, the correct answer states that the main role of a protocol is to enable data exchange between two entities on different systems.

The lack of required high frequency in the signal spectrum means that the upper limit of the transmission system range needs to be increased.

The correct answer is "од 300 Hz до 3400 Hz". This is because the standard frequency range for the speech channel is typically between 300 Hz and 3400 Hz. This range encompasses the majority of human speech sounds, allowing for clear and intelligible communication. Frequencies below 300 Hz are generally associated with low-frequency sounds such as rumbling or background noise, while frequencies above 3400 Hz are often not necessary for speech transmission.

The correct answer is 1 microsecond. The duration of one bit is determined by the signal speed, which is given as 1 Mb/s (1 megabit per second). Since there are 1 million microseconds in a second, the duration of one bit can be calculated as 1/1,000,000 seconds, which is equal to 1 microsecond.

A flat delay curve is preferred because it means that the transmission medium has a consistent and constant delay for all signals. This allows for more predictable and reliable communication as there are no variations in delay times. In contrast, linear, exponential, or logarithmic delay curves would indicate that the delay times vary depending on the signal, which can cause inconsistencies and potential data loss in communication.

The correct answer is "Експоненцијално" (Exponentially). The strength of the signal in wired media decreases exponentially with distance. This means that as the distance between the transmitter and receiver increases, the signal strength decreases at an exponential rate. This is due to factors such as resistance, interference, and attenuation in the wired medium.

The successful transmission of data depends on the characteristics of the transmission medium. This means that the properties of the medium through which the data is being transmitted, such as its bandwidth, noise level, and capacity, can affect the quality and reliability of the data transfer. Different transmission media have different characteristics, and these can impact the speed, accuracy, and efficiency of data transmission. Therefore, understanding and considering the characteristics of the transmission medium is crucial for ensuring successful data transmission.

The correct answer is "Улазни склоп, предајник, трансмисиони медијум, пријемник и излазни склоп" (Input device, transmitter, transmission medium, receiver, and output device). This answer accurately lists all the basic components of the communication model, which include the input device (where the message originates), the transmitter (which encodes and sends the message), the transmission medium (through which the message is transmitted), the receiver (which decodes and receives the message), and the output device (where the message is delivered).

A "кодер" is a device that is used to convert an analog signal into a digital signal.

The given signal consists of four periodic components: 3MHz, 5MHz, 7MHz, and 9MHz. The range of a signal is determined by the highest frequency component present in it. In this case, the highest frequency component is 9MHz. Therefore, the range of the signal is 9MHz.

ATM (Asynchronous Transfer Mode) standard has three layers. This standard follows the OSI (Open Systems Interconnection) model, which consists of seven layers. However, ATM only implements the bottom three layers of this model: the physical layer, the ATM layer, and the adaptation layer. These layers handle the transmission of data, the creation of ATM cells, and the conversion of higher-level protocols to ATM format, respectively. Therefore, the correct answer is 3 слоја.

Impulse noise is a type of noise that consists of sudden and short-duration disturbances in a signal. It can be caused by various factors such as electromagnetic interference or transmission errors. In the context of this question, the correct answer is "Дигиталним системима преноса" which means "Digital transmission systems" in English. This means that impulse noise is a fundamental source of error in digital transmission systems, indicating that it can disrupt the transmission and affect the quality of the digital signal being transmitted.

The given answer is correct because when data is sent directly from one layer of a machine to another layer of another machine, it refers to the physical layer. The physical layer is responsible for the actual transmission and reception of data bits over a physical medium. It deals with the physical characteristics of the transmission medium, such as electrical signals, voltages, and cables.

The syntax of a protocol refers to the formats of data and levels of signals used in the communication. It defines how the data is structured and the rules for transmitting and interpreting it. This includes specifications for the encoding and decoding of data, as well as the representation of different types of information. The syntax ensures that the data can be accurately understood and processed by both the sender and receiver of the communication.

If the speed of the alternating units and zero is 4 Mb/s, then the first harmonic would be 2 Mhz.

When a signal with harmonics at 1kHz, 3kHz, and 5kHz is passed through a high-pass filter with a cutoff frequency of 4kHz, only the harmonics above the cutoff frequency will be present at the output. Therefore, the only harmonic that will appear at the output is 5kHz.

The correct answer is "Релативне разлике снага два сигнала" which translates to "Relative differences in power between two signals." This suggests that the decibel is a measure used to compare the power levels of two signals relative to each other. It is not a measure of the absolute power or the sum or quotient of the power of two signals.

The correct answer is "Релативне позиције у времену у оквиру једног периода сигнала" (Relative positions in time within one signal period). This means that phase is a measure of the position of a waveform at a specific point in time within one complete cycle of the signal. It helps to determine the timing and synchronization of different signals or components within a system.

When signals of different frequencies are divided, it can lead to the occurrence of intermodulation noise.

SAP (Service Access Point) is a place where layer N can access the offered service of layer N+1. In other words, it is a connection point between two adjacent layers in a network protocol stack. It allows the upper layer to access the services provided by the lower layer.

The term "Pupinization" refers to the improvement of channel attenuation.

The correct answer is "Термички шум" (Thermal noise). Thermal noise refers to the random fluctuations in electrical signals that occur due to the thermal agitation of electrons in conductors. It is present in all electronic systems and is characterized by a continuous spectrum of frequencies. This type of noise is often referred to as "white noise" because it has equal intensity at all frequencies.

The correct answer is C = 2B log2 M. This equation represents the definition of Nyquist capacity, which is a measure of the maximum data rate that can be transmitted over a communication channel without error. In this equation, C represents the capacity, B represents the bandwidth of the channel, and M represents the number of different signal levels that can be used to represent the data. The logarithm base 2 is used because it represents the number of bits that can be transmitted per signal level. Thus, the equation C = 2B log2 M calculates the maximum data rate based on the bandwidth and the number of signal levels available.

Increasing the signal-to-noise ratio reduces the probability of errors in signal reception.

Никвист је посматрао канал без икаквог шума. This statement is in Serbian and it translates to "Nyquist observed the channel without any noise." This suggests that Nyquist studied the channel in a noise-free environment, without any interference or disturbances.

The correct answer is "Frequency and amplitude" because the Fourier analysis shows that every signal is composed of sinusoidal components of different frequencies and amplitudes.

The correct answer states that the effect of intermodulation noise is the production of frequencies that are the sum, difference, or multiple of the original frequencies. This means that when multiple frequencies are present in a signal, intermodulation noise can cause additional frequencies to be generated that are not originally present. These additional frequencies can interfere with the desired signal and cause distortion or degradation in the overall signal quality.

The correct answer is C = B log2 (1+S/N). This equation represents Shannon's capacity, which is a measure of the maximum rate at which information can be reliably transmitted over a communication channel. It takes into account the bandwidth (B) of the channel and the signal-to-noise ratio (S/N). The logarithm with base 2 is used because it represents the number of bits needed to represent each signal level. The equation C = B log2 (1+S/N) calculates the maximum capacity in bits per second.

Shannon considered thermal noise because it is a type of noise that arises due to random thermal agitation of electrons in a conductor. This noise is present in all electronic systems and can affect the accuracy and reliability of signal transmission and reception. By taking thermal noise into account, Shannon acknowledges its impact on the overall performance and quality of communication systems.

In this question, it is stated that a digital signal with a frequency of 4Mb/s is passed through a channel with a bandwidth of 1MHz. The concept of harmonics is related to the frequency components of a signal. In this case, since the bandwidth of the channel (1MHz) is greater than the frequency of the signal (4Mb/s), there will be no harmonics generated. Harmonics occur when the signal frequency is a multiple of the channel bandwidth, but in this scenario, the signal frequency is much lower than the channel bandwidth, so no harmonics will be present.

The correct answer is "Управљање информације и вођење рачуна о грешкама" which translates to "Managing information and error handling." This option refers to the semantic aspect of a protocol, which involves managing the information being communicated and handling any errors that may occur during the communication process. It does not include the other options such as data format, encoding, signaling, speed configuration, sequencing, or time synchronization.