Spectrum Analyzer

Everything there is to know about a spectrum analyzer

A spectrum analyzer is a device that displays a sign amplitude on two axes (x-axis, y-axis). The horizontal axis (x-axis) represents frequency, whereas the vertical axis (y-axis) represents amplitude. In its physical tool, it looks like an oscilloscope. Its full frequentness range measures the frequentness and magnitude of the sign given as an input. It is useful in measuring the spectral power for both known and unknown signals. It works on the principle of "super-heterodyne receiver." In electric industries, it has different applications as it measures the radio frequentness and audio signs. It displays the signs as well as the performance of circuits that produce those waves. By using spectrum, the organization becomes enabled to detect modifications and tell which part needs modification. Spectrum in medicine is useful for various applications such as X-Rays, detection of diseases and tumors, etc.

History of the spectrum analyzer

In the early 19th century, individuals considered the concept of spectrum analyzer as science fiction because, at that time, there was no introduction of magnetic and electric waves. James Clerk Maxwell, in 1865, published his dynamic theory of electromagnetic waves. It was the first time in history when electric and magnetic waves successfully moved through airwaves with light speed. Following the great effort of Maxwell's theory, it enabled many scientists to work further on magnetic and electric waves. First, this tool came into existence in the 1960s; it was merely a swept tuned tool at that time. After that, Fast Fourier Transform, also known as FFT, came into existence in 1965. In 1967 they introduced the first Fast Fourier Transform based analyzer. Conventional medical treatment methods were not much impressive because it was challenging to identify the broken bone, tumor, or heart diseases. But with the help of the spectrum technique, all problems became eradicated. Spectrum technique uses X-Rays, which helps to detect broken images. It shows results as signals for heart diseases as ECG and detection of other body problems using the spectrum technique. 

Indicate to use a spectrum analyzer

The spectrum analyzer tool checks the waves of wireless transmitters. It checks the quantity and quality of waves that are transmitting according to defined standards for purity emissions. On the other hand, it is also widely used for finding the level of different harmonics. While in telecommunications, it is useful to track the interference sources and occupied bandwidth. It also determines the digital and analog waves. In the field of medicine, it is useful in differential diagnoses to determine basic tissue parameters. The spectrum analyzer has many uses in various medical or clinic examinations. Many doctors also determine the effect of ultrasonic irradiations on myopia. 42 eyes of 21 patients were treated by it. There was an average decrease of 1.040 D in refraction in more than 71% of patients.  

General specification of the spectrum analyzer

A variety of equipment exist in the market with some general specifications for this equipment:

  • Use: To display electrical signs on screen, in the form of wavelengths
  • Source of power: Mostly line, but sometimes battery or USB 3.0
  • Max range for frequentness: 16 kHz - 14/26.5 GHz
  • Noise Floor (DANL at 1 GHz, Preamp On, dBm/Hz): -167
  • Tracking Generator: Mostly option 
  • Real-time feature: Yes 

Max input in dBm: + 33 dBm

  •  Max input in VDC: ± 40 VDC
  • Accuracy of amplitude: 95>#/p###
  • Max EVM on 802.11n: -49dB
  • Signs duration which is minimum: 0.419 μs

Types of spectrum analyzers

Many different types of spectrum analyzers exist, and they have their unique functions. Some of the most common types of tools are as follow:

Superheterodyne or Swept 

This type of equipment converts the input wave to the center frequentness, which is of a band-pass filter. The oscillator of voltage control runs across a different range of frequencies. Swept or super-heterodyne allows analyzation of full frequentness range for a device, the band-pass filter controls the minimum bandwidth of the detectable devices. Bandwidth and spectral resolution have inverse relations so, the greater the spectral resolution, the greater the bandwidth. The smaller the bandwidth, the greater the spectral resolution.

Fast Fourier transform, FFT

Many analyzers use the Fourier transforms, which decomposed individual frequencies from waves. These analyzers use frequentness of sampling at least twice the bandwidth as resolution frequency is inverse of time over Fourier transform and wave measured.


These analyzers gather real-time bandwidth as well as the incoming RF spectrum samples in a limited period. Fourier transform (FFT) algorithms convert the information because there is no "blind time in real-time collection of data." In the RF spectrum calculated, there are no gaps. This method is useful for getting information about the disease of any patient. FFT uses information from real-time and then converts to other domains. The detection of tumors, cancer, stones, or any disease becomes easy by using this method.

How to use a spectrum analyzer

The procedure for using this tool is as follows: 

  1. After turning on the device, the center frequency is added, which is useful to see all the wanted signal lines on display and other signals on the side of it.
  2. The span entered is the width of the frequency band displayed. Span and background noise levels have a direct relation. With the span reduced, the background noise level also reduces, making it easier to see signals closer to wanted ones. Body parts of patients generate different signals and frequencies. But for the desired frequency and signal, other signals are considered noise and are demised by using filters.
  3. Adjust the level controls. The reference level can also change to see the signal of interest on the display screen. Old analyzers had separate controls for RF and IF gain. The new analyzers have combined the control for both. A weak signal from medical equipment becomes magnified, and the desired information about the patient is gathered.
  4. Adjust the reference level to place the signals with peak toward the top of the display.
  5. Greater reference levels cause the display to disappear, so it is crucial to get it into the right region.
  6. A minimum of 20dB is required between signal and noise to be displayed onto the screen and for proper measurements.
  7. The noise level should be enough to add to the signals and effects the overall result.
  8. Adjustment of the span is a requirement to see the sideband on the display screen. 
  9. As span reduces, instruments display a much smaller bandwidth, which shows the sidebands.
  10. Reducing span also reduces the resolution bandwidth, which is the same as a radio resection bandwidth.
  11. The smaller the resolution bandwidth, the higher the resolution scan, which adds more detail to the display screen. A smaller resolution will give every little detail about the infection or disease present in the patient's body.
  12. Narrow bandwidth takes a longer time to perform the scan result apparatus. Hence, narrow resolution bandwidths to smaller overall scan widths; otherwise, they will take too long.
  13. The noise level falls for lower resolution bandwidth because noise is directly proportional to bandwidth.

When to use a spectrum analyzer


It is essential to check whether the wireless transmitter is working or not. The setting of standards for transmitters occurs at the federal level, and they should be followed. If an instrument is to full frequency range, it will measure an input signal's magnitude versus frequency. Known and unknown signals have a variation in their power, and the instrument helps to calculate the power of their spectrum. The power of the system is responsible for accurate detection. The greater the power the signal has, the greater the detection with less mixing of other noise signals, which makes the detection of diseases difficult. This equipment is useful in the following areas:


Direct observation

Networks have particular limitations, and these limitations are essential to be known for the surety of network connection. The bandwidth defines the maximum amount of wired or wireless connectivity which a network can provide to its users. Further, there are two types of bandwidths, digital and analog. Digital systems give details and results in digital form. In contrast, the analog system provides information about disease or tumors in an analog way. You can use spectrum analyzers for direct observations of both digital and analog bandwidths of a network.

Electrical signals 

Electrical signals hold immense importance, and it is essential to calculate them. The spectrum analyzer can help in the process of displaying electrical signals. If you have a frequency of electrical signals, then you can use the instrument to display its electrical signals. Corresponding signals, along with their frequency, are displayed as a frequency component on display. Electrical signals show the heartbeat and pulses or other responses of the patient's body, and it is easy to detect the disease from an electrical signal.

Market Leaders 

In 2023, the expected global retailing for the product is to reach a target of $1,813 million. In 2016 the retail was at $1068 million, and so the growing CAGR from 2017 to 2023 will be 7.7%. Some leaders for the product are as follows: 

Cobham Plc

There is a high demand for products made by Cobham Plc, so they have a good reputation in the hawk. Specifically talking about spectrum analyzers, they are leaders, and their products have good selling in the market due to accuracy and stability. Cobham also makes custom equipment according to the need of a customer. Then, they charge according to the customization. Its usage in the medical industry is very impressive. It gives results in proper ways to detect and analyze the disease.

Avcom of Virginia Inc.

Avcom of Virginia Inc is one of the market leaders for a spectrum analyzer, and they offer good quality equipment to their customers. They have been in the market for the past 30 years, and they offer a great experience related to the product. They offer high-quality equipment to all of their customers. 


Stanford Research Systems, Inc.

They have been market leaders for many years, and they deliver excellent quality to their customers. One of their best market products is SR770, which is much more affordable than some other products (analyzers) in the market. Equipment from ha Stanford research systems has a perfect bandwidth. They provide hard copy output and have a low-distortion source, which helps them be market leaders.

The complications of using a spectrum analyzer

There are very few complications that may occur with this instrument, and they are as follows: 

- The phase information of Swept type does not get calculated, which creates a problem at the end 

- In higher RF frequencies, FT analysis cannot work

- On the sampling rate of ADC, there is a complication 

- Both the FT analyzer and RF frequencies use a high amount of memory, and at the end, there is no memory left

- There is 10dB loss due to transient limiter

- If a good impedance is not used, then the clipping scheme will have some issues.



The use of a spectrum analyzer was essential to trace out the electrical signals. So, the invention of the device is fruitful. This instrument is also costly, and it is difficult for everyone to afford it. In the medical industry, the spectrum analyzer is beneficial. It provides every detail about the patient. As compared to conventional ways, the spectrum analyzer technique is the best, as it gives the exact location of the tumor, stones, or any other disease.