2016-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
Which of the following factors most affects the accuracy of a frequency counter?
Time base accuracy
Input attenuator accuracy
Decade divider accuracy
Temperature coefficient of the logic
What is an advantage of using a bridge circuit to measure impedance?
It is very precise in obtaining a signal null
It provides an excellent match under all conditions
It is relatively immune to drift in the signal generator source
It can display results directly in Smith chart format
If a frequency counter with a specified accuracy of +/- 1.0 ppm reads 146,520,000 Hz, what is the most the actual frequency being measured could differ from the reading?
If a frequency counter with a specified accuracy of +/- 0.1 ppm reads 146,520,000 Hz, what is the most the actual frequency being measured could differ from the reading?
If a frequency counter with a specified accuracy of +/- 10 ppm reads 146,520,000 Hz, what is the most the actual frequency being measured could differ from the reading?
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?
What do the subscripts of S parameters represent?
The port or ports at which measurements are made
The relative time between measurements
Relative quality of the data
Frequency order of the measurements
Which of the following is a characteristic of a good DC voltmeter?
High impedance input
High reluctance input
Low reluctance input
Low impedance input
What is indicated if the current reading on an RF ammeter placed in series with the antenna feed line of a transmitter increases as the transmitter is tuned to resonance?
There is more power going into the antenna
There is possibly a short to ground in the feed line
The transmitter is not properly neutralized
There is an impedance mismatch between the antenna and feed line
Which of the following describes a method to measure intermodulation distortion in an SSB transmitter?
Modulate the transmitter with two non-harmonically related audio frequencies and observe the RF output with a spectrum analyzer
Modulate the transmitter with two non-harmonically related radio frequencies and observe the RF output with a spectrum analyzer
Modulate the transmitter with two harmonically related audio frequencies and observe the RF output with a peak reading wattmeter
Modulate the transmitter with two harmonically related audio frequencies and observe the RF output with a logic analyzer
How should an antenna analyzer be connected when measuring antenna resonance and feed point impedance?
Connect the antenna feed line directly to the analyzer's connector
Loosely couple the analyzer near the antenna base
Connect the analyzer via a high-impedance transformer to the antenna
Loosely couple the antenna and a dummy load to the analyzer
What is the significance of voltmeter sensitivity expressed in ohms per volt?
The full scale reading of the voltmeter multiplied by its ohms per volt rating will indicate the input impedance of the voltmeter
When used as a galvanometer, the reading in volts multiplied by the ohms per volt rating will determine the power drawn by the device under test
When used as an ohmmeter, the reading in ohms divided by the ohms per volt rating will determine the voltage applied to the circuit
When used as an ammeter, the full scale reading in amps divided by ohms per volt rating will determine the size of shunt needed
Which S parameter is equivalent to forward gain?
What happens if a dip meter is too tightly coupled to a tuned circuit being checked?
A less accurate reading results
Harmonics are generated
Cross modulation occurs
Intermodulation distortion occurs
Which of the following can be used as a relative measurement of the Q for a series-tuned circuit?
The bandwidth of the circuit's frequency response
The inductance to capacitance ratio
The frequency shift
The resonant frequency of the circuit
Which S parameter represents return loss or SWR?
What three test loads are used to calibrate a standard RF vector network analyzer?
Short circuit, open circuit, and 50 ohms
50 ohms, 75 ohms, and 90 ohms
Short circuit, open circuit, and resonant circuit
50 ohms through 1/8 wavelength, 1/4 wavelength, and 1/2 wavelength of coaxial cable
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