Spectrum Analyzer vs. Network Analyzer

In summary, a spectrum analyzer can break down a signal into its various frequency components and a network analyzer can show the strength of a signal at various points in space.
  • #1
mikec
1
0
Hi all,

I was wondering if someone could clarify what the difference is between a spectrum analyzer and a network analyzer.

Thanks,

Mike
 
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  • #2
A spectrum analyzer breaks down a signal into its various frequency components and shows the strength of each component. A pure sine wave will only show a single peak while a distorted/modulated sine wave will show a number of sub peaks.

Network analyzer seems to be a more nebulous term and varies from simple signal/no signal to the ability to check for 'ghost' packets (ie bad termination causes unwanted reflections) With known propagation delay of cabling it can also tell the distance to the problem such as crushed or cut cable.
 
  • #3
A vector network analyzer will tell you reflection and transmission coefficients in both directions on a 2 port system. It will also show phase and delay differences between the ports. Both will do their thang over some frequency (or time) range.
 
  • #5
A spectrum analyzer is a receiver that scans all frequencies within its range, much like a scanner does.

It then displays the peaks and valleys of a signal during it's frequency sweep.


A network analyzer is a transmitter and a receiver built in one box, which are outputed as coax connections on the front panel, usally N connectors are used.

If you connect the network analyzer through a filter or amplifier, it will show it's frequency response, and calculate numerous parameters of your circuit at hand such as S, Z, Y, h paramers, smith chart and polar plots, phase, group delays, and even inverse Fourier transforms which will show you the time domain much like an oscillscope does.

One of the best in the world are made by Agilent, former HP. They are god in the RF community with max frequency ranges up to 325 GHz
 
  • #6
NoTime said:
A spectrum analyzer breaks down a signal into its various frequency components and shows the strength of each component. A pure sine wave will only show a single peak while a distorted/modulated sine wave will show a number of sub peaks.

Network analyzer seems to be a more nebulous term and varies from simple signal/no signal to the ability to check for 'ghost' packets (ie bad termination causes unwanted reflections) With known propagation delay of cabling it can also tell the distance to the problem such as crushed or cut cable.
Still I am confused that how a spectrum analyzer break down a signal into various frequency Components.
 
  • #7
testequipment said:
Still I am confused that how a spectrum analyzer break down a signal into various frequency Components.

(This thread is over 3 years old...)

Here's a tutorial for you:

http://www.spectrum-analyzer.info/Spectrum_Intro.aspx [Broken]

.
 
Last edited by a moderator:
  • #8
(wow can't believe it was that long - time goes by so fast)

Basically a spectrum analyzer works just like a radio receiver but with a wider tuning range, and tunes everything automatically.

The key is heterodyning or mixing, which is a process of converting a frequency of a signal to a higher or a lower frequency. To make a mixer work, you need to introduce another signal of some frequency, which is going to be either added or subtracted to the frequency of the incoming signal. Then filter the output which is held constant.

VCO (voltage controlled oscillator) is a circuit that changes frequency with a changing voltage. In the older radios, the VCO was tuned manually with a knob which was actually changing a voltage level on the VCO (in modern radios there is a synthesizer which does this digitally). In spectrum analyzers, the VCO is swept linearly with a ramp voltage and synchronized with the screen - and that gives you the x-axis on graph. To get the y-axis the incoming signal could be up-converted to a higher frequency by adding frequency of the incoming signal to the frequency of the VCO and filtering it out, amplifying and recovering amplitude with a diode...

This is just a basic overview, most spectrum analyzers will have more than 4 mixing stages, gazillion of oscillators, and synthesizers, and filters - that are designed to manipulate the incoming signal by changing its frequency, amplitude, and phase.http://img706.imageshack.us/img706/8835/48987296.png [Broken]
 
Last edited by a moderator:

1. What is the difference between a spectrum analyzer and a network analyzer?

A spectrum analyzer is a device used to measure and display the frequency spectrum of a signal, while a network analyzer is used to measure and display the characteristics of a network, such as impedance, gain, and return loss.

2. Which one should I use for analyzing my signal or network?

The choice between a spectrum analyzer and a network analyzer depends on your specific needs. If you need to analyze the frequency spectrum of a signal, a spectrum analyzer would be the appropriate choice. If you need to analyze the characteristics of a network, then a network analyzer would be more suitable.

3. Can I use a spectrum analyzer as a replacement for a network analyzer?

No, a spectrum analyzer and a network analyzer have different functions and cannot be used interchangeably. A spectrum analyzer does not have the necessary features and capabilities to accurately measure the characteristics of a network.

4. Do I need special training to use a spectrum analyzer or a network analyzer?

Yes, both spectrum analyzers and network analyzers require some level of training and understanding of signal analysis and network theory. It is best to consult with a specialist or attend training courses before using these devices.

5. What are the main applications of spectrum analyzers and network analyzers?

Spectrum analyzers are commonly used in industries such as telecommunications, aerospace, and defense to analyze signals and troubleshoot electronic devices. Network analyzers are widely used in the telecommunications industry for testing and analyzing the performance of networks and components.

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