How to Use a Spectrum Analyzer

How to Use a Spectrum Analyzer

Have you ever heard of Wi-fi testing? Spectrum Analyzer is the tool behind it. With a little bit of understanding and practice, you can easily use the advanced test equipment items.

Whether you are in a lab or the field, Best Spectrum Analyzer could be used for various applications like video broadcast, music production, interference hunting, voice and data communications, and spectrum management.

From the emission sources and base stations, spectrum analyzers put portray RF signals. Within the entire instrument’s frequency range, it measures the Input signal Vs. Frequency magnitude.

It is vital to know how to use a spectrum analyzer to monitor the RF circuit operations properly. How might you do so? Check out this article to find out!

What Does a Spectrum Analyzer Do?

When it comes to monitoring radio frequency, RF modules, and circuits, spectrum analyzers act as the key instrument.

A spectrum analyzer uses general electronic circuit design, RF design, service, electronics manufacture, and even repair.

What the test instruments do is display a graph of amplitude against frequency. Consequently, they become vital instruments to locate spurious signals, display, and measure signal bandwidths.

Now you know why it is essential to understand how to use a spectrum analyzer. Take a gander at the controls to gain a better understanding.

Once you dedicate some time to understand one of them, the whole process will be a breeze, no matter how critical the test instrument looks.

Although every spectrum analyzer is different, they hold the same basic concept across each of the test instruments– the same kinds of instruments with the same basic functions can be made.

Following this method, the same basic functions can be passed on to the other spectrum analyzers for usage. Of course, it happens after one test instrument has been put to work.

How to Use a Spectrum Analyzer

Any spectrum analyzer has several different interfaces and controls. Even though these elements of test equipment look complex, you can make good use of them eventually. With a bit of practice, you will also learn to employ the controls rightly.

The Display

When you look at this instrument, the first main element that catches your eye is the display. Portraying 10 major vertical and 10 major horizontal divisions, it has a display with graticule.

This analyzer’s horizontal axis is clearly labeled in frequency, with the highest frequency being on the display’s rightmost side.

Usually, a logarithmic scale is used to enable a signal over a vast range that is visible on a spectrum analyzer – signals may differ by 70dB, 80dB, or higher. An amount of 10dB every division is typically used.

As the scale is calibrated in dBm (that is, decibels relative to 1 milliwatt), it is easy to compare the level difference and check the two signals’ absolute power levels.

Furthermore, modern analyzers with a touch of digital technology frequently have soft keys that offer different functions around the display’s edge.

Adjusting the Frequency

Two selections can be opted to change the frequency of a spectrum analyzer. All the choices are independent of one another or entered with a keypad individually.

  • Center frequency

The center frequency selection adjusts the center of the scale’s frequency to a chosen value. It is this place where the signal to be set would be located.

Through this method, the primary signal would remain at the center of the display, and the frequency can be operated from either side.

  • Span

Span selection is the limit of the frequency coverage to be monitored or viewed when operating the spectrum analyzer. The spans may be distributed either as a bandwidth per division or the total span, which is visible on the screen’s calibrated section.

Another very available option is to adjust the scan’s start and stop frequencies. It gives a way to manifest the span as the disparity between the two frequencies equals the span. Reducing the span will permit the signal’s better resolution, allowing close-in components to be seen in the span.

  • Top and Bottom Frequency

This works as an alternative to the former two options. Many analyzers give you the chance to click the top and bottom or start and stop frequencies for functioning.

Attenuation And Gain Adjustments

Other controls can be used on the spectrum analyzer. However, most of them fall under these two categories, the first being associated with the attenuation or gain of sections inside the spectrum analyzer.

Spurious signals might be generated within the test instrument if its sections are overloaded. By adding extra attenuation with the input attenuator, you can prevent this hassle.

If too much weakening is inserted, the additional gain is needed in the later steps (IF gain). Background noises might spikes, masking lower level signals sometimes.

Therefore, to achieve optimum performance, a cautious choice of the appropriate gain levels must be made within the spectrum analyzer.

Modern test equipment contains a single gain control, usually known as a reference level control, that blends the IF gain controls and input attenuation. It adjusts automatically to gain the optimum setting. This way, both noise floors at one end and overload at the other are optimized.

Typically, the overall gain is aligned in a way that the signal’s peak is located at the top of the display – a sufficient margin is actually a space of 10 dB from the top. Via this method, spurious and the rest signals increase in amplitude, so they can be viewed easily.

If you lower the reference value too much, your signals will decline in value and become progressively closer to the stated residual noise level. There must be at least a 20 dB gap between the noise and signal for reasonable measurements.

Scan Rate

You must know that the spectrum analyzer functions by scanning the needed frequency span from low to high end of the necessary range. What is important is the speed with which this happens. Of course, the faster the scan, the speeder the measurement.

The rate is, however, hindered by 2 other elements. They are the filters used in the IF and also those that can be used to facilitate the reading. Without any time response, these signals might be missed, and the measurements rendered futile.

It is vital to keep the scan rate high to make the process feasible and quicker. Usually, the span, filter bandwidths, and scan rate are linked to ensure a premium blend.

When you have many measurements to be made – for instance, test times needed to keep minimum in electronics manufacturer or RF circuits must be characterized in RF design, scan rate plays a key setting.

Bandwidths

The rest of the controls involve the filter bandwidths. You will mostly see 2 types:

  • IF filter

It essentially offers the spectrum analyzer’s resolution in terms of frequency. Selecting a narrow bandwidth will allow signals, which are close together, to be seen.

As they are very narrow, these filters are not responsive enough to changes like the wider ones. Remember to use a slow scan rate while working with them.

While using the slow scan rates and narrow bandwidths, you need to measure the time by lowering the span that requires scanning. Although you need to use a slow scan rate, you can still reduce the range, therefore, reducing the analyzer’s scan time.

  • Video filter

You will often see that the filter bandwidth spontaneously linked with the scan rate and span on modern spectrum analyzers. Therefore, the optimum setting is selected for any given scenario.

The narrower this filter is, the finer the visible features. Similarly, your noise level is lowered. Note that the noise is proportional to bandwidth, so the higher the bandwidth, the more the noise.

As we mentioned before, one good rule of thumb is to make sure that there’s a 20 dB difference between the signal level and noise for sensible measurements.

Because these fine details can be viewed with the narrow filter bandwidth levels, the filter bandwidth can be referred to as a resolution.

Markers

One beneficial facility integrated on the virtually new spectrum analyzers is the application of markers.

The markers can detect particular parts of the waveform, helpful in recording the different signal levels. It can also compare figures like the spurious signals or harmonics level concerning the carrier.

Usually, the markers are used to adjust the peak, second peak, and so on or measure the level at a certain point– a knob or wheel is generally employed to set the frequency.

Controlled via soft function keys, the markers are available in the form of buttons surrounding the screen or soft keys.

Use A Spectrum Analyzer Now!

Now that you are aware of a spectrum analyzer’s how-to’s, it must become easy for you to implement it.

It is necessary to understand how amplitude, modulation parameters, and frequency vary over time over short and long intervals.

For your laboratory testing or other places where test instruments need to be tested, spectrum analyzers provide an exemplary RF signal chart.

If you have got all your queries on how to use a spectrum analyzer answered, what are you waiting for? Use one for your testing now!

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