Subelement L: L – Installation, Maintenance & Repair— Topic 77: Specialized Instruments
Question 3-77L3
Element 3 (GROL)What does the vertical axis of a spectrum analyzer display?
Explanation
A spectrum analyzer provides a visual representation of signals in the frequency domain. Its primary function is to display the strength of various frequencies present in a given input signal.
The **vertical axis** of a spectrum analyzer is dedicated to showing the **amplitude** (or power level) of the signals detected. This amplitude is typically measured in decibels (dBm, dBV), microvolts, or watts, indicating how strong a particular frequency component is.
Conversely, the horizontal axis displays frequency, showing the range of frequencies being analyzed. Options B (Duration) and D (Time) are incorrect because time is generally represented on the horizontal axis of an oscilloscope, which shows amplitude versus time. While some advanced spectrum analyzers can show time-related information (like spectrograms or persistence), the fundamental vertical axis display is amplitude. Option C (Frequency) is incorrect because frequency is displayed on the horizontal axis.
Related Questions
3-77L1 A(n) ____ and ____ can be combined to measure the characteristics of transmission lines. Such an arrangement is known as a time-domain reflectometer (TDR).3-77L2 What does the horizontal axis of a spectrum analyzer display?3-77L4 What instrument is most accurate when checking antennas and transmission lines at the operating frequency of the antenna?3-77L5 What test instrument can be used to display spurious signals in the output of a radio transmitter?3-77L6 What instrument is commonly used by radio service technicians to monitor frequency, modulation, check receiver sensitivity, distortion, and to generate audio tones?