The basic concept of spread spectrum technique is that the information waveform with small bandwidth is converted by modulating it with a large-bandwidth waveform (Hofmann- Wellenhof et al., 2001). Network Security. A. Jspm's Eniac Institute Of Computer Application, Wagholi, Pune. Second, the hosts have different masks, which puts them in different subnets. The extension of a pulse over many bit periods is shown in the next figure It is clear from the above figure that the square pulses in y(t) got spread out in the received signal r(t). A straight-through cable won't work. A. pure ALOHA 7. RF spectrum produced is much wider than baseband signal. It is used in UHF or Ultra high-frequency cellular systems, with frequency bands ranging from 800MHz to 1900MHz. Resistant to narrowband interference -Difficult to. Total Question - 24 Questions. With spread spectrum, data does not travel straight through a single RF band; this type of transmission is known as narrowband transmission.Spread spectrum, on the other hand, requires that data signals either alternate between carrier frequencies or constantly change their . frequency spectrum. 250+ TOP MCQs on Spread Spectrum Modulation Techniques and Answers ; 250+ TOP MCQs on Spread Spectrum Multiple Access and Answers ; Scattering of light by air born water droplets. Ans. Practice these MCQ questions and answers for preparation of various competitive and entrance exams. b. Underwater acoustic communication is a technique of sending and receiving messages below water. 8. Answer (1 of 5): Here is a subset of questions that every assistant professor candidate should ask during their interview: * Could you tell me about your research? (para 4) Answer: "Manipulative'. One of the great values of punctuality is that it gives discipline to life. There is no limit on the number of Users. UTIs have a wide variety of presentations. Code Modulation of the L1 Carrier. This is done by spreading the signal over a range of frequencies, that consist of the industrial, scientific, and medical (ISM) bands of the electromagnetic spectrum. Carrier sense multiple access (True /False?) Processing gain is the ratio of message bandwidth to signal bandwidth. Theoretical Justification for Spread Spectrum 3DJH RI Spread-spectrum is apparent in the Shannon and Hartley channel-capacity theorem: C = B × log2(1 + S/N) (Eq. Low probability of intercept B. C. Noise & Multi-path distortion. Spread-Spectrum Technology. Formation of diffused image of moon. 131) The advantages of using a CDMA technique over other spread spectrum techniques are. NEC 602 Digital Communication MCQ for unit 4 1. The underlying principle is that when a signal is spread over a wide bandwidth, a frequency selective fade will corrupt only a small portion of the signal's power spectrum, while passing the remaining spectrum unblemished. Verbal Ability. Different Types of Analyzers There are basically two ways to make frequency domain measurements (what we call spectrum analysis) 1] Fourier Transform Analyzer 2] Swept-Tuned Analyzer. However, switching regulators have a limited range of frequencies for which they can tolerate. Here you will find a great collection of Multiple Choice (MCQ)Questions in the category of Microsoft Excel with answer. It is a wireless technology used in the transmission of signals from places with high security and Noise reduction. Hence CDMA is robust against fading and noisy environment. The easy solution is just to set both masks to 255.255.255. Spread Spectrum modulation techniques are defined as being those techniques in which: - The bandwidth of the transmitted signal is much greater than the bandwidth of the original message, and - The bandwidth of the transmitted signal is determined by the message to be transmitted and by an additional signal known as the Spreading Code. Because of its inherent robustness, difficult to intercept, and hard to interference, the technique is the first choice in solving the given research problem. PART 4: MCQ from Number 151 - 200 Answer key: PART 4. Dispersion of light by air born water droplets. 25%. Ans. Hence these signals appear as noise. Ans. This set of Digital Communication Questions for entrance exams focuses on "Spread Spectrum, TDMA and FDMA". If the spreading is so severe, it may result in bit detection errors. b) overloading of transport-layer mechanisms. This document will explore basics concepts of spread spectrum for the remaining of the introduction and then it will explore the supporting concepts of the most used technique in spread . Then it becomes difficult for the jammers to attack our signal. Multiple users occupy different spectrum at a time. PART 7: MCQ from Number 301 - 350 Answer key: PART 7. Some are simple UTIs that can be managed with outpatient antibiotics and carry a reassuring clinical course with almost universal good progress, and on the other end of the spectrum, florid urosepsis in a comorbid patient can be fatal. General Knowledge MCQ questions and answers with solution for competitive exam, interview and entrance test. There are different types of wireless network such as wireless LAN, wireless MAN, and mobile devices network. C. 50%. Some good trivia questions and answers for work meetings include: Q: The birthday paradox states that in a group of 23 random people, there is a _____% chance of at least one shared birthday. The following illustration shows how near-far problem affects communication. True 5. Total Time - 30 minutes. Generally, fake news consists of stories that "report" on so-called facts and information that have no basis in fact, often with specifically fantastic headlines to encourage sharing on social media. As a general rule, most switching regulators can easily tolerate frequency variation of ±10%. Following are the benefits or advantages of CDMA: In CDMA, signal to be transmitted spread across the wide bandwidth due to spreading. This makes the signal more difficult to distinguish from noise and therefore more difficult to jam or intercept. allocated spectrum in the most efficient manner. A corona around the moon is seen when we view it on a fogy or misty night. Increased risk of fungal infection with broad spectrum antibiotic administration. This is the . Source: GPS For Land Surveyors. • Time division multiple access (TDMA): Every period of time can be divided into short seg- Anna University Mobile Computing Syllabus Notes Question Bank Question Papers Regulation 2017. The original ALOHA protocol is called ___. In which modulation schemes, the spreading of spectrum occurs? Figure 2. What is meant by anti-jamming? 1, 2 and 3 are correct b. There are five modules in the TCS Ninja Online Test 2022 which are -. Redundant 4. . Total Question- 26 Questions. Generally, higher frequencies are coupled with faster speeds but shorter range. Challenges: Spread Spectrum Frequency Hopping: The narrowband signal is dynamically switched in frequency. Example: Helium gas in a discharge lamp. a) Jamming b) Interception Spread type spectrum modulation is a process where signals are spread in the frequency domain using various spread spectrum techniques. 4. First and foremost, wireless uses radio spectrum, a finite resource. Aflatoxins are toxic, carcinogenic compounds released by fungi of the genus Aspergillus. The light emitted is composed of discrete colors. MS Excel Questions Answers (MCQ -Multiple Choice, Objective Type) Online test : Microsoft Excel is a spreadsheet software and is part of the widely used MS Office Package. 2, 3 and 4 are correct c. 1, 2 and 4 are correct d. All the four are correct. 1) In this equation, C is the channel capacity in bits per second (bps), which is the maximum data rate for a theoretical bit-error rate (BER). False. PART 7: MCQ from Number 301 - 350 Answer key: PART 7. It does not mean our body is resistant to antibiotics. a) True b) False 3. 5- Hybrid . B. Multi-path distortion. of ISI is that it will make it very difficult fo r the receiver to detect the transmitted bits. The main advantage of spread spectrum communication technique is to prevent "interference" whether it is intentional or unintentional. 2. . Anna University CS8601 Mobile Computing Notes are provided below. Spread Spectrum (SS) is a means of transmission in which the signal occupies a bandwidth inbandwidth in excessof the minimum necessary to send the informationof the minimum necessary to send the information. * How many recent tenure cases have failed? In any case, the most commonly used spread spectrum modulation technique is known as binary phase shift keying (BPSK). c) Carrier frequency d) None of the mentioned View Answer Answer: a Explanation: The width of the channel in frequency hopping spread spectrum corresponds to bandwidth of the input signal. (d) Find the word from the passage that mean the same as 'skilful at influencing in an unfair way. Bacteria and fungi are constantly finding new ways to avoid the effects of the antibiotics used to treat the infections they cause. The Important series of Spread Spectrum Techniques MCQs ( Digital Communications ) Mcqs are given below: Pseudo-Noise Sequence and Jamming 1. I) Estuary is place where the river fresh waster meets with ocean water II) This area is highly productive III) This area is highly unproductive IV) All of the above Which of above the statements is/are true? PART 5: MCQ from Number 201 - 250 Answer key: PART 5. The Mcqs having specific numbers in any written test. The spread spectrum techniques are useful for secure transmitter, because the receiver has to know the sequence used by the transmitter to recover the transmitter data. Wideband FM could be classified as a SS technique. Spread spectrum makes _____ difficult. The severe form includes chronic pulmonary manifestation, which may occur in the presence of underlying lung disease. The weakness of the signal makes it difficult to receive under cover. Spread spectrum signals are distributed over a wide range of frequencies and then collected and received back to the receiver. PART 6: MCQ from Number 251 - 300 Answer key: PART 6. c. Line sepsis is most common source. The most important feature of spread spectrum is its ability to___. . D. None of the mentioned. Frequency-hopping spread spectrum (FHSS) transmission is the repeated switching of frequencies during radio transmission to reduce interference and avoid interception. Explanation: In modulation schemes such as frequency modulation and pulse code modulation spreading of spectrum occurs but it cannot be considered as types of spread . Fourier Analyzer Parallel filters measured simultaneously CRT shows full spectral display A f f 1 f2. The transmitter of frequency hopping system is fed with encoding scheme such as a) Frequency shift keying b) Binary phase shift keying c) Frequency & Binary phase shift keying d) None of the mentioned . Frequency modulation. Better measure of security 4. Direct sequence spread spectrum (DSSS) transmission employs a chipping code to "spread" the transmission over a wider frequency band than it would normally occupy. Read the passage given below and answer the questions that follow: 1. Wireless networks working at a highest bandwidth of 11Mbps and 802.11b can be implementing with various products. PART 4: MCQ from Number 151 - 200 Answer key: PART 4. MORE ON: MCQ in Digital and Data Communications. B. The mild pulmonary illness may appear as a flu-like illness. View Answer: Answer: Jamming requires an interference signal of sufficient power in the same part of the spectrum the information signal occupies. Total Time- 40 minutes. A. Increased capacity 2. Urinary tract infections (UTIs) are among the most common causes of sepsis presenting to hospitals. Rather than using the 2.4 GHz band, it opted into using the 5 GHz frequency band. As the transmitted information is below the noise floor, it is difficult to intrude the CDMA spectrum. And this must be done in a way such that the quality of service doesn't degrade within 2- Direct-sequence spread spectrum (DSSS) 3- Time-hopping spread spectrum (THSS) . 7. resistance to narrowband interference. PART 3: MCQ from Number 101 - 150 Answer key: PART 3. 4. PART 3: MCQ from Number 101 - 150 Answer key: PART 3. FM "Processing Gain": SNR PHYS 1493/1494/2699: Exp. Q: Gaussian noise has _____ power spread _____ over all frequencies. As the spectrum is limited, so the sharing is required to increase the capacity of cell or over a geographical area by allowing the available bandwidth to be used at the same time by different users. Answer: c. Explanation: Mobile computing is referred to as human-computer interaction, in which the computer is required to be transported during general usage. Our purpose is to automatically determine the spreading sequence, whereas the receiver has no knowledge of the transmitter's code. a) Jamming b) Interception c) Jamming & Interception d) None of the mentioned Answer: c Explanation: Spread spectrum makes jamming and interception difficult and provides improved reception. Practice and Learn General Knowledge MCQ Questions and Answers for Government exams, Bank exams and other various exams . Q: In spread spectrum technique, the desired signal is multiplied _____ and interference signal is multiplied _____ Q: In which modulation schemes, the spreading of spectrum occurs? This method is called antijamming. This limits the number of wireless users and the amount of spectrum available to any user at any moment in time. A spread spectrum system is therefore designed to make these tasks as difficult as possible. The main advantage of using modulation techniques is that it reduces the size of the antenna in the circuit and improves the quality of signal in communication. Wideband FM could be classified as a SS technique. It is compatible with a number of calendar and contact management systems including Google Apps, Microsoft Office and . 30%. Multiple Choice Questions and Answers on Mobile Communication 1) The modulation technique used for mobile communication systems during world war II was a. Amplitude modulation b. The signal broadcast by the satellite is a spread spectrum signal, which makes it less prone to jamming. the power level of the user signal can even be as low as the background noise. Answer: a. CSMA stands for ___. MODULE 1 SPREAD SPECTRUM AND CDMA Spread Spectrum spreading the bandwidth needed to transmit data. Direct Sequence: The signal is spread to a much wider band. a. I) only b. II) only c. I) and II) d. III) Ans: c Ans. An intruder with no official access is never allowed to crack them. To achieve better speeds, it was the first to implement OFDM (Orthogonal . A method of transmitting radio signals switching between many channels, using a squence that is known by the transmitter and receiver. Result: The signal power is spread to a wider band, which makes it difficult to detect users. Why is it difficult to jam a spread-spectrum signal? Which system makes the detection difficult for all users other than the intended users? Advantages of CDMA: It uses a fixed frequency spectrum in an efficient way. MORE ON: MCQ in Digital and Data Communications. Spread spectrum makes ______ difficult. This concept is illustrated in Figure 3. It is useful to counter eavesdropping, or to obstruct jamming of telecommunications. c. d. e. 25) Regarding febrile oncology patients which is true? (/24). The ISM bands include the frequency ranges at 902 MHz to 928 MHZ and at 2.4 GHz to 2.484 GHz, which do not require an FCC license. Antibiotic resistance happens when the germs no longer respond to the antibiotics designed to kill them. Answer: C. Clarification: Spread spectrum makes jamming and interception difficult and provides improved reception. On the other hand, wide-band signals are noise-like and challenging to detect. This is due to: Diffraction patterns of air born water droplets. here CS8601 Mobile Computing notes download link is provided and students can download the CS8601 MC Lecture Notes and can make use of it. c) poor handling of unexpected input. Spread spectrum refers to the manner in which data signals travel through a radio frequency. 5.10. Answer: Option D. Solution: First, if you have two hosts directly connected, as shown in the graphic, then you need a crossover cable. Noise. DSSS is a form of CDMA (see Chapter 4 ). reject interference 6. Multiple choice questions on Digital Communication topic Multiplexing and Multiple Access. d) highly complex application security controls. a) Encoding b) Decoding c) Encoding & Decoding d) None of the mentioned View Answer 2. Q: Jamming is caused by Q: Which system makes the detection difficult for all users other than the intended users? Spread spectrum is a ______ technique. ANSWER: 1, 2 and 3 are . Diffraction MCQ Question 1. Spread spectrum (SS) is a wireless modulation technique in which the bandwidth (BW) and the power of the original information/data signal is increased by spreading it and thus making it resistant to electrical noise, diffusion, multipath distortion and making jamming and interference more difficult. Maximal sequencing is one of the more popular coding methods in a spread-spectrum system. RF spectrum produced is much wider than baseband signal. Reasoning Ability. Ans. Desired signal power will be much higher than the interfered signal power and . CDMA (Code Division Multiple Access) uses a digital modulation technique called Direct Sequence spread spectrum which spreads voice data over a very wide spectrum using a user or cell-specific pseudo-random codes. Hence, these techniques are used for military purposes. However, spreading the spectral density of the signal also reduces its power. 7 - Spectrum of the Hydrogen Atom Spread spectrum can be used to transmit a) Analog data b) Digital data c) Analog & Digital data d) None of the mentioned View Answer 3. * What are your expectations for tenure? Benefits or advantages of CDMA. It will break down and emit light. Download Solution PDF. Frequency modulation c. ASK d. FSK ANSWER: Frequency modulation 2) ———- introduced Frequency Modulation for mobile communication systems in 1935. a. Edwin Armstrong b. Periodically, harvests of nuts and grains are tainted by aflatoxins, leading to . CS8601 Notes all 5 units notes are uploaded here. Initially, the spread spectrum was adopted in military applications because of its resistance to jamming and difficulty intercepting. colors, called emission spectrum, depending on its composition. Similar Questions: Fast frequency hopping is The width of each channel in frequency hopping spread spectrum corresponds to The system should have Chips are the Direct system allows detection of signals whose psd level is To increase error probability, the processing gain should be In Vigenere method ______ is provided. BitPim is a cross-platform, open source application for managing data on cell phones that use the CDMA mobile telephony protocol . 1- Frequency-hopping spread spectrum (FHSS) . Fake news stories cover the gambit of topics, much like real news — politics, yes, but also health, entertainment, gossip, arts and culture . d. e. 26) Regarding GI bleed, which is true. IEEE 802.11a (WiFi 2) 802.11a was one of the first standards issued under the 802.11 umbrella in 1999. Because a spread-spectrum signal is, by definition, spread out over a very wide bandwidth, jamming can interfere with only a small fraction of the . Answer: (a). It involves mobile hardware, mobile software, and mobile communication. Which is better for avoiding jamming? We have to get up in time. Spread spectrum is a technique that spreads the transmit signal over a wide signal bandwidth in order to reduce the effects of flat-fading, ISI, and narrowband interference. a. Matlab simulations will examine the code III. Firstly, the transmitted signal should be difficult to detect by an adversary/jammer, i.e., the signal should have a low probability of intercept (LPI). Total Question- 30 Questions. Q: Uncertainty in the delay measurement is _______ to rise time of the pulse. 5.11.List the advantages and disadvantages of FH-SS. The radio meter consists of Q: Spread spectrum signals are used for Q: Uncertainty in the delay measurement is _________ to the bandwidth of signal pulse. (i) Spread spectrum: spread spectrum technique of implementing audio steganography is used as one of the prime components of the proposed solution. Spread spectrum has immunity from. FM "Processing Gain": SNR Low probability of detection . 1). It is very difficult to handle frequency selective fading in the receiver , in which case, the design of the receiver is hugely complex. As shown in the illustration, user A is far away from the receiver and user B is close to the receiver, there will be big difference between desired signal power and interfered signal power. a. This makes it difficult to distinguish the user signal from the background noise and thus hard to detect. This technology focusing on frequency-hopping spread spectrum and direct-sequence spread spectrum which have two approaches. In spread spectrum technique, the desired signal is multiplied . DC_mCQ_Unit4_5_6.docx. 1. But instead of a pseudorandom binary sequence (PRBS), an 11-bit Barker code is used as the spreading sequence. Instead of trying to mitigate frequency selective fading as a whole (which occurs when a huge bandwidth is allocated for the data transmission over a frequency selective fading channel), OFDM mitigates the . Solution: Perfect synchronization and pattern knowledge Challenges: Sensing Duration & It also allows transmission of information/data, audio and video calls, etc. 1. 6. Q: The radio meter consists of Q: Spread spectrum signals are used for b. Octreotide is of no additive benefit to sclerotherapy in banding. View Answer Report Discuss Too Difficult! Q1. Spread spectrum techniques are effective in combating the frequency selective fading that takes place in multipath channels. Some advantages of spread spectrum are a) Low susceptibility b) Immunity to jamming c) Reduced interference d) All of the mentioned 2. For example, frequency modulation of ±10% will be much more effective at EMI reduction than frequency modulation of ±2% 1. Each signal can be upconverted to a frequency band by multiplying it by a sinusoid at the center frequency of that band, and then filtering out any out-of-band content (see ECE 3500). a) weak or non-existent mechanisms for authentication. In spread spectrum the information signal is modulated by a wideband pseudo-noise (PN) signal, resulting in a much larger transmit signal bandwidth than in the original signal. That means the germs are not killed and continue to grow. Main idea: put a large voltage across the gas. 2. PART 6: MCQ from Number 251 - 300 Answer key: PART 6. The clinical presentation of the disease has a wide-spectrum presentation which makes diagnosis difficult. It is therefore everyone have to learn / remember the related Spread Spectrum Techniques MCQs ( Digital Communications ) Mcqs. BitPim can be used to back up data stored on a phone and synchronize contacts and calendars. Numerical Ability. * Do you have a faculty mentoring program? The CDMA provides one of the most secure modes of communication due to its spread spectrum property. Spread Spectrum (SS) is a means of transmission in which the signal occupies a bandwidth inbandwidth in excessof the minimum necessary to send the informationof the minimum necessary to send the information.
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