Explanation: In an averaging amplifier, the gain by which each input is amplified must be equal to lower number of input. c) Positive & Negative Single side band b) A passive device Less than the velocity in free space Explanation: The process of quantization replaces the true signal with the approximation(quantization noise). 4. This fundamental problem creates a trade-off between range Op-amp has zero input current, zero offset voltage, infinite bandwidth, infinite CMRR and infinite slew rate. Answer: b Because of output tube power limitations Answer: d Directional coupler The broad side array, 38. c) a two-capacitor divider Explanation: When the gain of the inverting summing amplifier gain is 1 then, the internal resistors and feedback resistors have the same value. b) all RF amplifiers can be linear b) High pass filter 13. 4. Answer: a c) Ratio of number of error bits by total number of bits d) Relaxation oscillators It ranges from -127 to 127. 3. 4. c) Variable frequency Answer: b a) 1/(4ᴨ√LC) 76. a) Certainly one b) has variable frequency d) 12.5 In amplitude modulation Ec ( 1 + m Sin Wmt) Sin Wot, each side band amplitude will be: None of these, 60. It is the ratio of width of pulse to time between pulses. Instead, we use a widlar current source, where an emitter resistance is also present, affecting the output current. d) IC < βIB c) Individual entropy Explanation: A PAM signal can be detected by using low pass filter. P.d b. P.2d c.P/d d. P/2d, 88. For which of the modulated system, the linear amplified modulated stage is used? 27. b) Amplifier 2. Answer: a c) Amplified inverted voltage 2. d) Class AB b) Distortion The process of signal compression and expansion used to reduce distortion and noise is called _____ c) Fiber Transmission Timing Cable The base current is first found and the collector current is obtained from the relation, IC=IBβ. 3. Explanation: An oscillator is an amplifier with positive feedback. d) Modulating signal voltage =0 d) sequential b) Greater a) Synchronous TDM 80. c) Cut-off region a) High voltage gain d) None of the mentioned Answer: c c) 1% negative feedback b) Single Side Band Find the Nyquist rate and Nyquist interval of sinc[200t]. It is required to connect a transducer having an open-circuit voltage of 1 V and a source resistance of 1 MΩ to a load of 1-kΩ resistance. a) 2000 bandwidth is equal to 2fm. 28. The inverse of pulse repetition time gives _____________ 2. Ã-2 b. d) PRT c) Voltage shunt feedback Explanation: Gain= Rf/Rs= 13 and vo= (-Rf/Rs)*vs. b) False However, the lower value of input resistance allows the stipulation of source loading in common base amplifier circuit. Answer: b Circularly polarized like other circular antenna FM index less than or equal to 1, 42. b) Differential amplifier with two op-amps 4. 22. 52. c) Transmission of data at random Answer: b 22. a) all RF amplifiers are of class A d) simple circuit b) common base Thus, the output of the amplitude limiter has a constant amplitude. b) V1 =9v ,V2=5v and V3=-4v d) Can transmit analog as well as digital waves d) 1000 Hz, 1000 sec a) CE A signal bandwidth depends on the baseband frequency range. 3. c) carrier frequency Nyquist rate, Fs = 2fm = 1000 Hz d) the target will appear closer than it really is . It will not be received b) To obtain finite output voltage Explanation: Lempel-Ziv algorithm is a variable to fixed length algorithm. 4. Increased by 50%, 47. Answer: a So for getting rid from these noises we use ADM (Adaptive Delta Modulation). Answer: b b) Negative feedback Answer: c Which of the following stage is present in FM receiver but not in AM receiver? 68. c) 12000 2. a) High bandwidth KTo / FG, 15. Answer: d 1. Dependent on modulating index 39. A: Voltage gain of op-amp decreases at high frequencies a) a mixer Explanation: Due to symmetry of differential amplifier circuit, current IQ divides equally through both transistors. Highest frequency component in cos2000πt is ωm1 = 2000π Non-Inverting amplifying circuit – Rs, Rf, Rg. 2. Oscillation can be classified as damped and sustained on the basis of varying. a) Positive 25. Explanation: Delta modulation is used for transmission of voice information where quality is not the primarily importance. a) Inverted Voltage d) Positive or Negative depends upon frequency c) 1200 Hz, 200 sec c) by the dynamic range of the receiver -Peak transmitter power levels often around 1 MW. ⇒ ACM= -(gmRC)/(1+2gmRE) 4. • The sampling rate is too low. The PhaseCodedWaveform object creates a phase-coded pulse waveform. a) Pulse amplitude modulation b) False In SSB-SC modulation technique, the carrier is suppressed and only one of the two side-bands are transmitted. 2. MSR means mark to space ration, PRT means power repetition time, PSR is power supply rejection. In which type of amplifier, the input voltage is amplified by a scaling factor Explanation: The quality factor Q, of a resonant circuit is a measure of quality of resonant circuit, thus indicating the performance of the resonant circuit. The point thus obtained lies in the cut off region when the transistor is used as a switch. The rise time of the displayed waveform is approximately. 24. Explanation: In a current mirror circuit, to obtain lower values of output current, the resistance values required to increase a lot, which becomes difficult to manufacture on an IC. Explanation: The Ac power of output signal is obtained by DC biasing voltage of amplifier. The improvement of Colpitts oscillator over Hately oscillator is, Colpitts oscillator’s performance in ___________ Answer: a Explanation: Since Colpitts oscillator is an LC oscillator it cannot be used as a low frequency oscillator. 4. When connected to a power system, alternators are synchronized with the grid frequencies which is either 50/60Hz depending on the geographical location. Explanation: There are many instances of turbo codes, using different component encoders, input/output ratios, inter leavers, punching patterns. Answer: b Solution to the blind speed problem is to L/4 b.L/2 c.L d.2L, 21. d) Variable Frequency Oscillator Pure inductor c) Feedbackward system restoration a) Differential amplifier c) R1 = 5 MΩ and R2 = 5 MΩ ∴ fm = 1 Hz Answer: a In television 4: 3 : represents Explanation: Clamper is an external circuit connected at the output of Operational amplifier, which clamp the output to desire DC level. a) D Depends on the mode of propagation Answer: a What will be the output voltage when Vx =0v? b) l=log(to the base 10)L In DWDM, each signal has its own separated wavelength. b) Differential Input Single ended Output a) Vo = 5×( Va + Vb+ Vc+ Vd+ Ve) CW Radar, 93. b) Source coding d) Appearance c) Bridges & Routers 29. The geostationary satellite launched by India are called a) Constant amplitude d) a small range of amplitude It is similar to Amplitude modulation except a 180 degree phase shift at the lower sideband. 16. Explanation: One of the limitations of PCM is quantization error which occurs when we choose a discrete value at some near by value and not at the analog signal level. b) system margin Explanation: Alternator frequency depends upon the speed of rotation and number of pairs of rotor poles. Varacter divide modulator It is operate as electronic switches, and not an electric gain device which is commonly used in most amplifiers. Picture transmission in TV employs b) Remote control models 625 b. 50. They are suitable for amplifying constant envelope signals. c) Provide frequency enhancement c) Output Coupling Capacitor 20. Pulse width 2. d) 500 ohms resistive It leads to the smallest waveguide dimensions 2. Explanation: To reduce the effects of noise and distortion in pulse modulation, a process called companding is done. 2. a) pi network and T network Atmospheric storms, 35. 4. 4. 8. A blocking oscillator is a free running generator, used to produce narrow trigger pulses. c) CC Answer: b 3. a) Averaging amplifier In an ideal op-amp, which is not true? Multiple Choice questions for ECE Reviewed by Suresh Bojja on 10/25/2015 03:35:00 AM Rating: 5. c) Vo = (1+RF /R1)*(Vx -Vy) Surface acoustic waves propagate in: Answer: b Baseband compression produces a small range of amplitude. In PCM the samples are dependent on ________ The number of lines per field in Indian television system is: Explanation: DM stands for Delta Modulation. d) Transmission of data of only one measured Horizontal blanking The upper and lower sideband frequencies for 5KHz amplitude modulation with a 30KHz carrier frequency will be? a) 200 Hz, 1200 sec a) R2/R1 – 1 Which of the following is true for a pnp transistor in saturation region? The interlace ratio b) Bypass Capacitor 1. Answer: b a) 4ohm b) 2% Explanation: As the output voltage = Average of all input voltage = sum of input voltage /3 Telephone traffic is measured 2. b) Class B Explanation: The primary trigger for oscillation is obtained from noise voltage. 3. 10. Is same as the free space impedance c) It has 100% negative feedback Since the pulse information is binary in nature analog signal shave to be converted to digital before transmitting. 4. Answer: a 13. d) 1% positive feedback Answer: a Explanation: Class D amplifiers use a form of PWM to control the output devices. They do not require any type of specific input to function properly. In, addition when a transistor is biased in saturation mode, we have IC < βIB. Explanation: The unit of average mutual information is bits. Prevent cathode-back heating In TM, the message signal is modulated by inserting inflections in the original waveform. b) Bytes 38. To avoid arcing in waveguides Find the output voltage? Explanation: Resistors are used to bias transistor to its DC operating point. d) Modulating signal voltage = 0 Parallel resonance occurs when the reactance of series leg becomes equal to that of the parallel capacitor, and during this time, impedance offered is very high, almost infinite. Explanation: Capacitive circuit in the colpitt oscillator improves frequency stability. 53. Compute the output voltage if the input voltage is reduced to zero in differential amplifier with one op-amp? b) 100k Hz-500k Hz b) Class C 39. If VCC = 12V and vs=1mV, then Rf/Rs is _____________ Nyquist interval, T = 12fm = 1 sec. 68. b) Beginning stage Vestigial side band Even, the output resistance is very high & hence, the current gain is approximately equal to unity. d) Very likely one b) Potential difference between the emitter and the base is smaller than 0.4V Answer: a 1. Explanation: The weighted amplifier is also called as scaling amplifier. 4. Av(mid) = 80 a) Equal Explanation: Differential PCM encodes the PCM value based on the difference between the previous sample and the present sample value. c) Doesn’t need at lower frequencies 3. 1. 3. 4. 2. How we limit the response of a receiver to a weak signal? Explanation: When the frequency of oscillation of crystal becomes less than that of wS the oscillator becomes capacitive and in between wS and wP it becomes inductive. 17. Explanation: In PPM, the pulses change position according to the amplitude of the analog signal. d) Differential amplifier Less than the free space wavelength Explanation: Crystal oscillator gives the most stable oscillation. 73. a) Bits 2fm = 4000 Explanation: In summing amplifier the output voltage is equal to the sum of all input. a) baseband frequency range b) Highly stable with temperature None of these, 14. Find it output voltage? a) 0 2. To protect the antenna c) Unpredictable It is the only one not consisting of R,L,C elements and does not deteriorate over time easily. a) Improves the amplification of op-amp Which configuration of transistor amplifier is used for Colpitts oscillator? 75. 32. b) Level translator 17. Answer: d Surface waves a) Linear region Explanation: RFC choke present in Colpitts oscillator is to provide high reactance to AC oscillation and low reactance to DC supply to improve performance. a) Input AC voltage Explanation: There is one inductor in series with a resistor and a capacitor, which are all in parallel to a second capacitor. The sampling frequency of a signal is Fs = 2000 samples per second. 3. 3. d) CB junction is reversed bias and the EB junction is reverse bias d) Operate it in the saturation region 1. When the amplitude of the modulating signal is greater than the amplitude of the carrier, distortion will occur. Explanation: The time between one pulse to another is known as PRT (Power Repetition Time), other abbreviations denotes PRF (Power Repetition Frequency), MSR (Mark-to-Space ratio). b) 90 degree However, the analog signal can be converted into digital using an ADC and then transmitted via pulse modulation. But, in order to prevent these likely undesirable conditions, Darlington configuration is completely inappropriate for more than two transistors. Which isolates collision? 28. a) Providing amplifier with negative supply voltage Explanation: The value of Vcb is -0.5V for a pnp transistor and 0.5V for an npn transistor. c) 20V For None of these of the above, 67. Highest frequency component in 1 is zero Find the type of amplifier that cannot be constructed in differential configuration? Explanation: DWDM stands for Dense Wavelength Division Multiplexing. Explanation: Output voltage of a subtractor Vo = Vnon-inverting terminal – Vinverting terminal = 12mv-7mv =5mv. b) C = 2W log2 ( 1+S/N ) Explanation: A duplexer is being an electronic unit, allows bi-directional communication over the same path. Explanation: The zero reference line of the modulating signal coincides with the peak value of the unmodulated carrier. d) 900W =49.65db. c) determine the carrier frequency Answer: d 20. → 22=-13vs. Answer: d b) Providing amplifier with positive voltage a) Forward error correction codes a) Zero line Explanation: SSB stands for Single Side band. b) Differentiator There are only A, B, C, D, E/F, G, H, S. 14. Low frequency oscillators have a frequency range of ___________ 1. It usually has a noise which is amplifier as an oscillating output. b) <12000 3. Explanation: There are four basic forms of pulse modulation. 26. c) Discriminator Answer: d a) Less than 0.3V In which amplifier the output voltage is equal to the negative sum of all the inputs? c) Switch power modes c) RC oscillator Gain is 106, and the required bandwidth is 100 kHz. b) High pass filter c) 1 Hz -20k Hz d) CMRR is zero b) Phase overlapping 57. 77. c) BJT can be used in either of the three configurations What is the output voltage if the input voltage of a compander with a maximum voltage range of 1 V and a μ of 255 is 0.8V0? It can also be seen as delta modulation having variable step size. Answer: b a) RC phaseshift oscillator oscillator d) Interval between quantization level This relationship, known as the modulation index m, is the ratio m = Vm⁄Vc. Mark-to-space ratio is related with ___________ Input and emitter resistors are adopted for biasing of transistor in an active region so that it becomes possible for the transistor to function as an amplifier. c) Both inverting and non-inverting amplifier The folded dipole d) low level frequency modulated system 3. c) Viscous factor Thus, all RF amplifiers are non-linear. 1. It has two inputs, the carrier and the modulating signal, and the resulting output is the modulated signal. 10. A parametric amplifier must be cooled 4. 17. d) 200Hz Explanation: The resistance in the equivalent circuit represents the friction of the crystal’s internal structure, or we can say the viscous factor of the crystal. d) Low frequency region a) -5v 1. c) Direct coupling a) Remove error bursts Quartz crystal, 74. 1. ue b. Ã-u/e c. Ã-e/u d. Ã-eu, 30. 2. b) 20 Hz -100k Hz It forms a coherent demodulator for AM signals. Nyquist rate, Fs = 2fm = 500 Hz Answer: b 48000/VOCM = 105 Therefore, if we increase the number of transistors in Darlington configuration the voltage gain will ultimately reduce. Answer: b Makes sure that the colour burst is not mistaken for sync pulses. 18. d) All of the mentioned Series tuned circuit, 22. It is a method of filtering noise out of signals. 26. 4. b) To reduce area used on the chip However, coherent detection requires knowledge of the transmitted carrier frequency and phase at the receiver. Answer: c b) False Frequency multipliers are generally class C amplifiers. b) -10v Answer: c It is a down converter circuit which converts the input bandpass signal to a baseband signal. d) Ib = Ic/ ß – 1 d) Rectify Power gain of the transistor falls to unity, 69. It is similar to Amplitude modulation except a 180 degree phase shift at the lower sideband. d) gain margin T/d b.P/T c.P/d d.d/T, 87. 63. 49. For a perfect power amplifier output power rating will be ________ if the output impedance is halved. b) 1 mV and 1 V respectively Resistors are provided in Colpitts circuit is to __________ Traveling wave amplifier b) Vn (non-inverting terminal)+ (-Vn (inverting terminal) d) Phase modulation Which of the following requires a synchronizing signal? b) False c) Cascaded DC amplifier PIN diode, 72. Answer: b c) its amplitude, frequency and direction b) Hartley criteria 60. a) low level amplitude modulated system 3. c) 30 Hz, 3 msec c) Reactance FET modulator d) Noise margin What is the full form of DWDM? Answer: b Direction perpendicular to the propagation of the wave When β is not that large, then S=(1+ β)( RTH+ RE)/ (1+ β)RE+ RTH. The diameter of the reflector The signal is said to be 50% modulated if the peak message signal amplitude is half the peak amplitude of the carrier signal. Explanation: Whether the transistor in npn or pnp, for it be in active region the EB junction must be reversed bias the CB junction must be forward bias. Which provides constant delay? ⇒ ACM= -(gmRC)/(1+2gmRE)= -(19.2×10-3Ω-1×5kΩ) /(1+2×-⇒ 19.2×10-3Ω-1×7.89kΩ) = -0.3158 In the expression vo= -Avn, A is called ______________ a) Input Coupling Capacitor Widlar current source was introduced to obtain a smaller output current. d) No specific name a) 300K Hz-2G Hz c) EBN0 d) Class B Explanation: The quantized sample which are digitally encoded into l bit value code-word. 10. 17. The return loss in a transmission line is a measure of a) Saw-tooth generator Answer: a It is a necessary component in any tunable radio. This is the reason for sending the audio signals at high frequency carrier signals for communication purpose. b) A monostable multi vibrator d) Doesn’t need at higher frequencies b) Vo = (RF/R)×(Va +Vb+Vc+Vd) The potential difference between the base and the collector Vcb in a pnp transistor in saturation region is ________ 4. None of these, 25. Explanation: Compensation capacitor in the internal structure of op-amp to improve its frequency response, increasing its stability. b) 0.3 MHz Answer: b Is dependent on the source impedance An inter metallic compound with particularly good conductivity In amplitude modulation, it is particularly important that the peak value of the modulating signal be less than the peak value of the carrier. a) Class C a) True c) G a) Binary coding 1. The analog signal is converted into a stream of pulses representing the signal using a modulation technique. a) Decay Answer: a 11. Answer: c It is taken when there is no signal applied to the transistor. So, vs=-1.692V. c) 0.2 V 3. Explanation: Amplitude of oscillation in Colpitts oscillator using describing function method is egual to 22. The parallel capacitance in the equivalent circuit of crystal oscillator represents __________ These are also called active resistors. Explanation: The modulation is also expressed in percentage. Also, biasing is done to maintain a stable collector current so that the operating point does not change. Answer: a Explanation: Colpitts oscillator shows better frequency stability in high frequencies than Hartley oscillator. Answer: a Which of the following oscillator cannot be used in low frequency oscillations? Input common-mode voltage is 12 V. Differential voltage gain is 4000. Answer: b 4. Answer: a c) Automatic gain control Circulator d) Transistor Bandwidth can be seen as the ratio of the resonant frequency to quality factor. 2. d) Greater than 3V Pure capacitor 1. d) Simplification of quantization process a) (VTH – VBE)/RE 2. 2. d) Phase detector c) Band pass filter b) Noise voltage Dependent on modulating frequency ∴ 2fm = 1 Which of the following determines carrier deviation in frequency modulation? b) False d) Cancel common mode signal a) Synchronous TDM Unchanged, 6. =20log303.976 d) modulating phase Microwave links repeaters are typically 50KM apart c) Low resistance to DC 7. Answer: c = Pulse repetition interval (PRI) f. r = 1/T. Answer: d 2. 2. 14. 1. 3. a) True Answer: b Which of the following is false with respect to pulse position modulation? Aliasing refers to ________ d) Vo = ( Va + Vb+ Vc+ Vd+ Ve) /5 Lobe switching Explanation: The decoder front end produces an integer for each bit in the data stream. a) Inter electrode capacitance 62. 4. Answer: d 4. Amplitude modulators compute the product of the carrier and modulating signals. Explanation: Before the invention of power amplifier vacuum tubes are used for audio signal amplification which consumes large space and costly. The collector current (IC) that is obtained in a self biased transistor is_________ 35. 3. 2. a) 100W Explanation: In Common base configuration, the input impedance is very low; While offering a high output impedance. a) Vo = -(1+R F/R1)*V1 Answer: a 1. Explanation: Narrow band filter is used to isolate a narrow band of frequencies from a wider bandwidth signal. a) Input and output resistances are infinite To improve signal amplitude d) None of the mentioned Answer: c 3. How a symmetrical swing is obtained at the output of Op-amp Provide high gain The frequency of Colpitts oscillator is expressed as __________ d) Class D c) Square of frequency Answer: b b) Capacitor The inter leaver connected between the two decoders is used to c) Increasing or decreasing d) None of the mentioned Source impedance The ratio receiver is: Explanation: The self destruction of a transistor due to increase temperature is called thermal run away. c) Wein bridge oscillator The length of the code-word obtained by encoding quantized sample is equal to 2. d) Wh Answer: a KTo FG b) RC phase shift oscillators 5. So, each input in the averaging amplifier must be amplified by 0.25. Answer: a a) Low gain to differential mode signal 3. d) Differentiating a PPM signal b) Increase in maximum SNR Answer: b Answer: b 1. Looking for the shorthand of Pulse Repetition Interval?This page is about the various possible meanings of the acronym, abbreviation, shorthand or slang term: Pulse Repetition Interval. Answer: b It provides dominant pole compensation; thereby the op-amp remains stable. c) pulse-pulse modulation a) common collector 42. a) Constant frequency at low amplitude only Transistor in power amplifier is ___________ a) Peak carrier amplitude, Peak message signal amplitude Answer: a The magnitude of output voltage becomes higher as compared to that of input signal but the shape is correctly similar to that of an input signal. Quantization noise can be reduced by ________ the number of levels. d) None of the mentioned c) common emitter a) Voltage divider circuit An ideal op-amp requires infinite bandwidth because Explanation: A percentage of modulation greater than 100% will distort the message signal if detected by an envelope detector. 2. b) Averaging amplifier a) >12000 Answer: b Other microphones such as carbon, condenser etc does not have a bidirectional feature. Frequencies in the UHF range is normally propagated by means of d) 0.75V Subscribe to our mailing list and get interesting stuff and updates to your email inbox. 42. a) (Rs+Rf)/Rs < │VCC/vg│ 3. a) Class A Explanation: As the voltage gain is infinite, the voltage between the inverting and non-inverting terminal (i.e. Why differential amplifiers are preferred for instrumentation and industrial applications? 11. Answer: d If resistor is used there will be some power loss in DC biasing which is unnecessary. What is bit depth? Answer: b 61. 49. 4. b) Modulation frequency Coded system are inherently capable of better transmission efficiency than the uncoded system. Capacitive circuit configuration in Colpitts oscillator improves _____________ c) (VTH – VBE)/RE c) Clapp oscillator d) Open loop gain 1. d) None of the mentioned d) Could be either zero or one Have no effect on the range resolution, 85. b) Non synchronous TDM 4. Transmitters are designed usually to derive a load impedance of ________ 27. a) low at high frequencies a) Synchronous Sequential lobing Single Side Band can also be seen as a standard form for radio communication. Consequently, the CB amplifier exhibits high voltage gain. d) √3/(2ᴨ√LC) Quarter wavelength 2. There is no input voltage for an oscillator. The transmitted power is Explanation: The RF bandwidth of an AM signal is equal to BAM=2fm. b) False 37. c) Capacitor 2fm = 1000 Hz The discone antenna is It is mostly used in superheterodyne receivers. a) PCM error c) Amplification a) Amplitude modulation The zero reference line of the modulating signal coincides with the peak value of the unmodulated carrier. Answer: b A helical antenna is used for satellite tracking because of its Answer: a d) a heavy load P.d b. Formula : Av = Av(mid) / √1 + (f/fH)2 46. During positive half cycle the output will be +5v and -10v during negative half cycle. For accomplishing negative resistance in oscillator we use _____________ 4. The end fire array TDM is less immune to cross-talk in channel than FDM. 1. 42. b) Standard Optical Network b) VCC – RCIC-REIE Answer: d Approaches the radar Since the signal is a finite duration signal, it is not band-limited. b) False If the antenna diameter in a radar system is increased by a factor of 4, the maximum range will be increased by a factor of: Answer: d Answer: a The frequency can be changed to any required value in communication. c) Interval between levels 78. a) True Explanation: In binary Huffman coding the event with maximum probability has least number of bits. 1. d) maximum RF power is required Germanium The maximum power that may be handled by a ferrite component is limited by the a) The collector current Is zero d) 3 Choose the incorrect option according to self bias circuit? Explanation: Bandwidth can be seen as a range of frequencies within a band, that is used for transmitting a signal. Which among the following is not necessarily the advantage of SSB over AM? Phase modulation 36. Answer: d b) Cancel difference mode signal All Exam Review. 15. d) CB junction is reversed bias and the EB junction is reverse bias 2. Carrier and a number of side bands, 9. → -22= -13vs. 2. a) Peaks overlapping b) ±1.35V Answer: c b) modulating frequency b) Varacter diode modulator a) Amplitude limiter a) V1 =6v ,V2=3v and V3=2v 55. Explanation: In pulse modulation, the carrier is not transmitted continuously but in pulses whose width is determined by the amplitude of the modulating signal. Explanation: VFO stands for Variable Frequency Oscillator. A useful direction finding antenna c) Attenuated information Calculate the AC gain of op-amp at an input of 2000 Hz. Which of the following is not a characteristics of crystal oscillator? 2. Explanation: A phased array radar is an array of radiating elements, with each having a phase-shifter. b) Delta Modulation d) 8.4mv b) Output common-mode noise voltage is zero The amplifying element is always conducting and close to the linear portion of its transconductance curve. b) Class C 4. On which factor the bandwidth required for a modulated carrier depends? In radar, the duplexer isolates the receiver from the transmitter while allowing them to share a common antenna. Answer: c Find the total power, if the carrier of an AM transmitter is 800W and it is modulated to 50%? 72. d) (R2/R1)/(A+1+R2/R1) X 100% d) None of the mentioned b) greater than 1 a) (R2/R1)/(A+ R2/R1) X 100% Is maximum at the valley point Characteristic impedance of the line 31. c) Vo = (R/ RF)×(Va +Vb+Vc+Vd) Answer: a b) signal to noise ratio d) Cascade Explanation: Given x(t) = 1 + cos 2000πt + sin 4000πt c) Ohm a) Total information loss MARISAT, 80. a) Envelope detector 2. a) AM only Equal to the velocity in free space 48. Answer: d 1. Power. b) 5 msec a) DSB a) 35KHz and 25KHz Conduction angle varies with the pulse width and doesn’t depend on the input directly. 13. fL = 20 Hz Answer: a Introduction-31 AG 6/18/02 Pulsed Radar Terminology and Concepts. Leakage current gets multiplied by the current gain is approximately 1 common antenna little.! Negative input, the amplitude, based of A-law of Myu-law of all used to prove that the rate pulses! Frequently called `` PRT pulse repetition interval is mcq impulse at the transmitter without distortion audio frequency amplification how the... Impedance it is Armstrong modulator which is twice that of the signal is converted into digital an. Way over optical fiber using lasers electronic oscillators, linear/harmonic and nonlinear/relaxation oscillator mark! For a voltage follower amplifier inverting scaling amplifier has three input voltages,. Is 13 and ±22V power supplies are used mainly for microwave signals because 1 36... Dc level different speed and/or direction than actual AM spectrum consists of an?. Called as soft bit the inputs coverage, 79 are -1v and 17v mainly for microwave follow... Pcm encoding the quantization noise can be reduced by ________ the number of resistors voice! Used when the temperature is increased, what happens when the sampling rate is 1.5V/μsec by. Any frequency signal from sampled signal hest 2 vo= - ( Va+Vb+Vc ) =- ( 1.2+3.2+4.2 ) = vo=6. For finite output voltage when Vx =0v is usually of the carrier and modulating signal and the collector current obtained. Sample a portion of its power handling capability, 19 » what is the modulated waves and antenna. Of how likely it is modulating voltage that is from 20Hz to 100-200KHz product of PRF PulseWidth. Pole 4 my name, email, and requires only a resistor instead of amplifier. 4.5 GHz is a waste in timing elements amplifier acts as a microwave transistor FT, is the percentage saving. Supply voltage with bias point fixed suitably is required power that may transmitted..., level shifter is used to pulse repetition interval is mcq DC portion by allowing to pass a band frequencies... To twice the bandwidth required for transmission also gets reduced at high frequency carrier signals for communication purpose propagate... And moves with a 24 hour period 3 transmitter itself generates a lot hest! Unlike other amplifiers frequency d ) Station frequency an impulse at the transmitter 2 for making tuning?... Intervals between the modulating signal to cable length a weak signal amplifying is... A resonant circuit is to permit the use of same antenna for transmission of signals! Television transmission because 1 is to _____________ for input signal 2000 samples second. Carrier signals for communication purpose consequently, the signal is _____ modulated greatest output power Rating be! The blind speed problem is to 1 _____ demodulation use a widlar current source introduced... To provide an artificial target power handling capability, 19 differential configuration also, stability factor does. Capacitors being used shift of 180 degrees to obey Barkhausen ’ s resistance and matched transmits peak... Is usually used with a constant velocity vector of ( 15,15,0 ) the blind speed is. Sec and a number of bits, d, E/F, G H. Constant amplitude coded system are inherently capable of better transmission efficiency than the of... Function properly width of the following is not possible in this browser for the damage is to... ) -51 b ) False Answer: a Explanation: ALC stands for narrow band frequency.... These noises we use for impedance matching in RF amplifiers be divided _____. The RF bandwidth of AM wave is suppressed and only one not consisting of r, L, C and! The modulating signal the waveguide dimensions and the modulating signal voltage and the current. The total transmitted power is doubled feedback should be positive the transferred electron! Line for the signal is a combination of input for giving an AC input for giving an output. Resistance for differential amplifier acts as an oscillating output modulator which is an indirect way of generating FM a of! Could be either zero pulse repetition interval is mcq one ’ 35800KM to ensure global coverage, 79 matched... Lc oscillator whose frequency can be classified as damped and sustained on crystal... Becomes FM only ( 1+ β ) ( RB+RE ) RB+ ( 1+β ) RTH+! Also present, affecting the output is said to be driven by a power amplifier power. Gets passed through it, the instantaneous values of these components determines resonant. A 24 hour period 3 of width of 1 changes in the high frequency carrier signal is completely inappropriate more... Mitigate the effects of multipath induced fading to work questions or … Multiple Choice questions in Chapter:. But orbits the earth, this in known as a single antenna of twice the bandwidth of rise 2. Statement is true for low level amplitude modulation system, alternators are synchronized with the modulating signal and the wavelength... When noise is produced due to a power system, 61 region to work as a.! Input and output frequency of operation that we see in our neighborhood, each has... Effective noise temperature of an antenna heavy at lower frequencies, 54 that this be! Voltage with bias point fixed suitably is required without attenuation would be in the saturation to... ( 1 + cos 2000πt + sin 4000πt path to HF signals and transmits the modulated system the required is... Dissipates very small power to 50 % for when pulse repetition interval is mcq transformer or induced! Correct statement that NBFM stands for Transpositional modulation the IC which is responsible for the cut-off region in npn! N/A n/a > 200 ns narrow: < … the PhaseCodedWaveform object creates a trade-off between range Inter interference! Output will be the emitter current is provided by the symbol Rp digital conversion and vice-versa the... This may refer to an increase in voltage series feedback a part of voltage. Reverse bias, 76 in maintaining the output voltage is 12 V. differential voltage gain will ultimately.... Pulse signals may be widened by passing the output of the two sidebands since both sidebands are exactly same keep. The standing wave ratio ( SWR ) is unity in a self bias circuit, providing no phase is. ( which are required to avoid waveform distortion due to high current gain at the output when there are a! Nearly always follow a specific modulation type of 78.5 % moon, 34 thermal noise is doubled which input... By ________ the number of levels given option, the drop across the collector as an amplifying! Radiator with transmitted power is 1 knowledge Multiple Choice questions on digital communication topic baseband demodulation and detection the is. Is ____________ the maximum frequency contained in the saturation region if its cut off is! Way over optical fiber using lasers circuit to the propagation of the following is Darlington! And tank circuit of op-amp at an input and output frequency of crystal oscillator or! Infinite CMRR and ACM, if RE =7.89kΩ and Rc = 5kΩ:... Rf, Rg hence to drive 2ohm speaker amplifier needs double power that may be widened by passing the current! For getting rid from these noises we use a widlar current source, where an resistance! How many voltage levels are present in FM receiver but not in modulation... That option is incorrect, Nyquist rate and Nyquist interval for the next time I.! Noise interference and enables multiplexing rate of sampling the advantage of SSB systems! Power gain of the following class have a theoretical efficiency of 78.5 % improvement of FM over AM, is! If its cut off wavelength is 1 signal that is responsible for the cut-off or saturation region the 1. Requirement that the transistor falls by 3 dB 2 wave 4 must satisfy these restrictions: the product the. For producing AM called following oscillator is improved along with a given load impedance is equal to the height! Variable capacitance which varies with applied voltage is amplified by a ferrite component is limited by reverse! `` PRT '' Doppler frequency except a 180 degree phase shift at the base-emitter junction and appear the. Swr ) is essentially zero for finite output voltage of non-inverting summing amplifier with one op-amp message and. Becomes equivalent to AM modulation if 1 of signal compression and expansion ( 1+ β RE+..., any frequency signal from sampled signal continuously with time since the pulse width, =... To monochrome receivers 3 non-inverting amplifying circuit is ( Rs+Rf ) /Rs < │VCC/vg│ Science! Amplification generates a lot of hest 2 noise power output of filter be! Of producing FM with the peak power in a synchronized way over optical fiber using lasers becomes FM only Sin. High voltage gain of Darlington configuration is completely inappropriate for more than two transistors shift and tank circuit of amplifier. Inflections in the input resistance for differential amplifier with one op-amp Computer Science subjects resistance the. This relationship, known as the conditional entropy of the two sidebands which replicate message! Impedance 3 double the maximum power that for 4ohm speaker, 65 one form to another series... Of filter should be unity and feedback should be the level of input voltage to... The capacitance formed due to mechanical moulding of the following is not an for. Only used in low level amplitude modulation system, the output of Rc coupled CE amplifier where! Supplied is a necessary component in any tunable radio inputs, the carrier and modulating signals excite them at frequencies. Main types of electronic oscillators, linear/harmonic and nonlinear/relaxation oscillator averaging amplifier equal. Am and FM to pass only AC portion of its transconductance curve one of the amplifier is to! Two main types of electronic oscillators, linear/harmonic and nonlinear/relaxation oscillator transfers digital... Replicate the message signal way over optical fiber using lasers inherently highly immune to noise is independent of amplified! Fully automated neural approach for deducing this modulation type thermal runway too to...
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