Correct Answer : Amplifier
Explanation : An amplifier is a component that increases the amplitude of the input signal. The increase in amplitude is measured as gain. Gain is the ratio of the voltage of the input signal vs output signal.
Correct Answer : 14000
Explanation : Gain = output voltage/input voltage = 700/0.05 = 14000.
Correct Answer : 400mV
Explanation : Gain = output signal voltage / input signal voltageOutput signal amplitude = 20 x 0.02 = 400mV.
Correct Answer : dBm
Explanation : When the gain or attenuation of a circuit is expressed in decibels, implicit is a comparison between two values, the output and the input. An often used reference level in communication is 1 mW. When a decibel value is computed by comparing a power value to 1 mW, the result is a value called the dBm. It is computed with the standard power decibel formula with 1 mW as the denominator of the ratio.
Correct Answer : 64
Explanation : dB = 20 log(5/0.003) = 20 log 1666.67 = 20 x 3.22 =64.4.
Correct Answer : 240
Explanation : Total gain = product of individual gains = 6 x 8 x5 = 240.
Correct Answer : 87.5mW
Explanation : Gain = power out / power inPower in = power out / gain = 7/80 = 87.5mW.
Correct Answer : Resistance offered to ac current by coil and capacitance
Explanation : Both coils and capacitors offer an opposition to alternating current flow known as reactance, which is expressed in ohms. Like resistance, reactance is an opposition that directly affects the amount of current in a circuit.
Correct Answer : Phase of current leads the voltage
Explanation : In addition to resistance of alternating current flow, a capacitor alters the phase difference between the current and voltage. The capacitor lowers the phase of the voltage and hence the current leads the voltage.
Correct Answer : Phase of voltage leads the current
Explanation : In addition to a resistance of alternating current flow, an inductor/coil alters the phase difference between the current and voltage. The inductor/coil lowers the phase of the current and hence the voltage leads the current.
Correct Answer : 350KHz
Explanation : Bandwidth = resonant frequency / Quality factor = 28 x 106 /80 = 350KHz.
Correct Answer : 533MHz
Explanation :
Correct Answer : 37.68
Explaination : Quality factor = Q = 2πfL/R = (2 x 3.14 x 90 x 106 x 3 x 10-6)/45 = 1695.6 / 45 = 37.68.
Correct Answer : Decreases
Explanation : Capacitative reactance is inversely proportional to the operating frequency and is given by the formula Xc= 1/2πfC where C is the capacitance value in Farad.
Correct Answer : 700.16?
Explanation : Capacitative reactance =Xc= 1/2πfC = 1/(2 x 3.14 x 2 x 106 x 100 x 10-12) = 796.2Ω.
Correct Answer : Increases with less capacitance value
Explanation : The lead wires of capacitors behave as a complex RLC circuit and generate stray capacitance. This can be reduced by shortening the length of the lead wires or using chip capacitors. However, decreasing or increasing the value of capacitance does not affect stray capacitance.
Correct Answer : Increases
Explanation : Inductive reactance is directly proportional to the operating frequency and is given by the formula Xf= 2πfL where L is the inductance value in Henry.
Correct Answer : 4522Ω
Explaination : Inductive reactance = XL=2πfL = 2 x 3.14 x 18 x 106 x 40 x 10-6 = 4522Ω.
Correct Answer : Frequency selective circuit
Explanation : A filter is a frequency-selective circuit. Filters are designed to pass some frequencies and reject others. Filters are used to reduce noise and increase selectivity.
Correct Answer : Passive filters
Explanation : Simple filters created by using resistors and capacitors or inductors and capacitors are called passive filters because they use passive components that do not amplify. In communication work, many filters are of the passive LC variety, although many other types are used.
Correct Answer : All pass filters
Explanation : An all pass filter passes all frequencies equally well over its design range but has a fixed or predictable phase shift characteristic. Filters normally attenuate the signal applied for some values of frequency whereas an all pass filter retains the signal level at all frequencies.
Correct Answer : High pass filter
Explanation : An RC coupling circuit is an example of a high-pass filter because the AC component of the input voltage is developed across R and the DC voltage is blocked by the series capacitor. Furthermore, with higher frequencies in the AC component, more AC voltage is coupled.
Correct Answer : Roll off
Explanation : Roll off is also called the attenuation rate, roll-off is the rate of change of amplitude with frequency in a filter. The faster the roll-off, or the higher the attenuation rate, the more selective the filter is, i.e., the better able it is to differentiate between two closely spaced signals, one desired and the other not.
Correct Answer : Insertion loss
Explanation : Insertion loss is the loss the filter introduces to the signals in the passband. Passive filters introduce attenuation because of the resistive losses in the components. Insertion loss is typically given in decibels.
Correct Answer : 996Ω
Explaination :
Correct Answer : Low pass filter
Explaination : The simplest form of low-pass filter is the RC circuit shown in the figure. The circuit forms a simple voltage divider with one frequency-sensitive component, in this case, the capacitor. At very low frequencies, the capacitor has very high reactance compared to the resistance and therefore the attenuation is minimum. Thus allowing lower frequencies to pass through while attenuating higher frequency signals.
Correct Answer : Harmonic
Explanation : A harmonic is a sine wave whose frequency is some integer multiple of a fundamental sine wave. The third harmonic of a 2-kHz sine wave is a sine wave of 6 kHz.
Correct Answer : 50%
Explanation : Duty cycle is the ratio of the duration of the positive alteration t1 to the period T expressed as percentage. D= t1⁄T*100 = t1⁄2t1 * 100 = 50%.
Correct Answer : 14Khz
Explaination : The frequency of 7th harmonic sine wave = 7 x 2KHz = 14KHz.
Correct Answer : True
Explanation : Fourier analysis allows us to determine not only the sine wave components in any complex signal but also how much bandwidth a particular signal occupies. Although a sine or cosine wave at a single frequency theoretically occupies no bandwidth, complex signals obviously take up more spectrum space.
Correct Answer : 1.75?s
Correct Answer : 58.3MHz
Correct Answer : Spectrum analyzer
Explanation : The test instrument for producing a frequency-domain display is the spectrum analyzer. Like the oscilloscope, the spectrum analyzer uses a cathode-ray tube for display, but the horizontal sweep axis is calibrated in hertz and the vertical axis is calibrated in volts or power units or decibels.
Correct Answer : 0.76
