Tektronix MSO64 — преимущества использования спектрального анализа сигналов [169/628]

Using Spectrum View

Spectrum View provides a time-domain view of the frequency components of a signal. Spectrum View is standard in 5/6 Series

MSO instruments. Spectrum View is an option in 4 Series MSO instruments.

Spectrum View concepts

Typical oscilloscope displays show electrical signals as a graph of time on the x-axis versus amplitude on the y-axis (time

domain). A spectrum trace shows the same electrical signals as a graph of frequency on the x-axis versus amplitude on the y-

axis (frequency domain).

NOTE. Spectrum View is standard in 5/6 Series MSO instruments. Spectrum View is an option in 4 Series MSO instruments.

Figure 17: The time and frequency domain components of a waveform.

All time-domain signals can be defined as a composite of discrete sine waves, each with their own frequency, magnitude, and

phase. The frequency-domain waveform (or spectrum trace) is a Fast Fourier Transform (FFT) decomposition of the time-domain

signal into its constituent sine wave frequency components.

There are several advantages to examining signals in the frequency domain:

■

It is easier to analyze signal noise characteristics. In the time domain, noise can appear as a fuzzy waveform, but in the

frequency domain you can determine if it is broadband, random noise, or perhaps cross-talk from another signal on your

DUT.

■

It is easier to analyze and measure the distortions on signals. Although a 1% distortion on a sine wave may not be

discernable in the time domain, it will be very obvious in the frequency domain as harmonics of the signal.

■

Wireless communication measurements are described in the frequency domain in terms of frequency bands and channels.

A spectrum trace lets you focus analysis on the relevant frequency range and make specialized measurements such as

occupied bandwidth and modulation quality.

4/5/6 Series MSO Help

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