E4A Test equipment: analog and digital instruments; spectrum analyzers; antenna analyzers; oscilloscopes; RF measurements

- [[E4A01]] (A)
Which of the following limits the highest frequency signal that can be accurately displayed on a digital oscilloscope? #card
	- [[A.]] Sampling rate of the analog-to-digital converter
	- [[B.]] Analog-to-digital converter reference frequency
	- [[C.]] Q of the circuit
	- [[D.]] All these choices are correct
--
- [[E4A02]] (B)
Which of the following parameters does a spectrum analyzer display on the vertical and horizontal axes? #card
	- [[A.]] Signal amplitude and time
	- [[B.]] Signal amplitude and frequency
	- [[C.]] SWR and frequency
	- [[D.]] SWR and time
--
- [[E4A03]] (B)
Which of the following test instruments is used to display spurious signals and/or intermodulation distortion products generated by an SSB transmitter? #card
	- [[A.]] Differential resolver
	- [[B.]] Spectrum analyzer
	- [[C.]] Logic analyzer
	- [[D.]] Network analyzer
--
- [[E4A04]] (A)
How is compensation of an oscilloscope probe performed? #card
	- [[A.]] A square wave is displayed, and the probe is adjusted until the horizontal portions of the displayed wave are as nearly flat as possible
	- [[B.]] A high frequency sine wave is displayed, and the probe is adjusted for maximum amplitude
	- [[C.]] A frequency standard is displayed, and the probe is adjusted until the deflection time is accurate
	- [[D.]] A DC voltage standard is displayed, and the probe is adjusted until the displayed voltage is accurate
--
- [[E4A05]] (D)
What is the purpose of using a prescaler with a frequency counter? #card
	- [[A.]] Amplify low-level signals for more accurate counting
	- [[B.]] Multiply a higher frequency signal so a low-frequency counter can display the operating frequency
	- [[C.]] Prevent oscillation in a low-frequency counter circuit
	- [[D.]] Reduce the signal frequency to within the counter's operating range
--
- [[E4A06]] (A)
What is the effect of aliasing on a digital oscilloscope when displaying a waveform? #card
	- [[A.]] A false, jittery low-frequency version of the waveform is displayed
	- [[B.]] The waveform DC offset will be inaccurate
	- [[C.]] Calibration of the vertical scale is no longer valid
	- [[D.]] Excessive blanking occurs, which prevents display of the waveform
--
- [[E4A07]] (B)
Which of the following is an advantage of using an antenna analyzer compared to an SWR bridge? #card
	- [[A.]] Antenna analyzers automatically tune your antenna for resonance
	- [[B.]] Antenna analyzers compute SWR and impedance automatically
	- [[C.]] Antenna analyzers display a time-varying representation of the modulation envelope
	- [[D.]] All these choices are correct
--
- [[E4A08]] (D)
Which of the following is used to measure SWR? #card
	- [[A.]] Directional wattmeter 
	- [[B.]] Vector network analyzer 
	- [[C.]] Antenna analyzer 
	- [[D.]] All these choices are correct
--
- [[E4A09]] (A)
Which of the following is good practice when using an oscilloscope probe? #card
	- [[A.]] Minimize the length of the probe's ground connection
	- [[B.]] Never use a high-impedance probe to measure a low-impedance circuit
	- [[C.]] Never use a DC-coupled probe to measure an AC circuit
	- [[D.]] All these choices are correct
--
- [[E4A10]] (D)
Which trigger mode is most effective when using an oscilloscope to measure a linear power supply’s output ripple? #card
	- [[A.]] Single-shot
	- [[B.]] Edge
	- [[C.]] Level
	- [[D.]] Line
--
- [[E4A11]] (D)
Which of the following can be measured with an antenna analyzer? #card
	- [[A.]] Velocity factor
	- [[B.]] Cable length
	- [[C.]] Resonant frequency of a tuned circuit
	- [[D.]] All these choices are correct