Extra-Study/pages/E4A.md

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  • C. Calibration of the vertical scale is no longer valid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