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

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