69 lines
3.6 KiB
Markdown
69 lines
3.6 KiB
Markdown
E4B Measurement technique and limitations: instrument accuracy and performance limitations; probes; techniques to minimize errors; measurement of Q; instrument calibration; S parameters; vector network analyzers; RF signals
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- [[E4B01]] (B)
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Which of the following factors most affects the accuracy of a frequency counter? #card
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- [[A.]] Input attenuator accuracy
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- [[B.]] Time base accuracy
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- [[C.]] Decade divider accuracy
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- [[D.]] Temperature coefficient of the logic
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- [[E4B02]] (A)
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What is the significance of voltmeter sensitivity expressed in ohms per volt? #card
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- [[A.]] The full scale reading of the voltmeter multiplied by its ohms per volt rating is the input impedance of the voltmeter
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- [[B.]] The reading in volts multiplied by the ohms per volt rating will determine the power drawn by the device under test
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- [[C.]] The reading in ohms divided by the ohms per volt rating will determine the voltage applied to the circuit
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- [[D.]] The full scale reading in amps divided by ohms per volt rating will determine the size of shunt needed
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- [[E4B03]] (C)
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Which S parameter is equivalent to forward gain? #card
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- [[A.]] S11
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- [[B.]] S12
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- [[C.]] S21
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- [[D.]] S22
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- [[E4B04]] (A)
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Which S parameter represents input port return loss or reflection coefficient (equivalent to VSWR)? #card
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- [[A.]] S11
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- [[B.]] S12
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- [[C.]] S21
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- [[D.]] S22
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- [[E4B05]] (B)
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What three test loads are used to calibrate an RF vector network analyzer? #card
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- [[A.]] 50 ohms, 75 ohms, and 90 ohms
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- [[B.]] Short circuit, open circuit, and 50 ohms
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- [[C.]] Short circuit, open circuit, and resonant circuit
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- [[D.]] 50 ohms through 1/8 wavelength, 1/4 wavelength, and 1/2 wavelength of coaxial cable
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- [[E4B06]] (D)
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How much power is being absorbed by the load when a directional power meter connected between a transmitter and a terminating load reads 100 watts forward power and 25 watts reflected power? #card
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- [[A.]] 100 watts
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- [[B.]] 125 watts
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- [[C.]] 112.5 watts
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- [[D.]] 75 watts
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- [[E4B07]] (A)
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What do the subscripts of S parameters represent? #card
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- [[A.]] The port or ports at which measurements are made
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- [[B.]] The relative time between measurements
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- [[C.]] Relative quality of the data
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- [[D.]] Frequency order of the measurements
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- [[E4B08]] (C)
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Which of the following can be used to determine the Q of a series-tuned circuit? #card
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- [[A.]] The ratio of inductive reactance to capacitive reactance
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- [[B.]] The frequency shift
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- [[C.]] The bandwidth of the circuit's frequency response
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- [[D.]] The resonant frequency of the circuit
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- [[E4B09]] (B)
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Which of the following can be measured by a two-port vector network analyzer? #card
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- [[A.]] Phase noise
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- [[B.]] Filter frequency response
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- [[C.]] Pulse rise time
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- [[D.]] Forward power
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- [[E4B10]] (B)
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Which of the following methods measures intermodulation distortion in an SSB transmitter? #card
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- [[A.]] Modulate the transmitter using two RF signals having non-harmonically related frequencies and observe the RF output with a spectrum analyzer
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- [[B.]] Modulate the transmitter using two AF signals having non-harmonically related frequencies and observe the RF output with a spectrum analyzer
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- [[C.]] Modulate the transmitter using two AF signals having harmonically related frequencies and observe the RF output with a peak reading wattmeter
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- [[D.]] Modulate the transmitter using two RF signals having harmonically related frequencies and observe the RF output with a logic analyzer
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- [[E4B11]] (D)
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Which of the following can be measured with a vector network analyzer? #card
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- [[A.]] Input impedance
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- [[B.]] Output impedance
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- [[C.]] Reflection coefficient
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- [[D.]] All these choices are correct
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