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Why R&S name some models Signal and Spectrum Analyzer
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2X:
Hello,
why R&S name some models Signal and Spectrum Analyzer and some others just Spectrum Analyzer. As I know a Signal Analyzer (cost more) show more things over a Spectrum Analyzer. I read the below post but I couldn't find any big difference except what "Dago" say on his post. Do you have any idea about this distinction in naming... maybe the spectrum analyzer have some other advantages over a signal analyzer where R&S want to point out?

Differences between Signal Analyser & Spectrum Analyser?
https://www.eevblog.com/forum/beginners/differences-between-signal-analyser-spectrum-analyser/

The Rohde & Schwarz signal and spectrum analyzer portfolio
https://www.rohde-schwarz.com/products/test-and-measurement/signal-and-spectrum-analyzers_63665.html


I am thinking to buy the below for my bench:
https://www.rohde-schwarz.com/products/test-and-measurement/benchtop-analyzers/rs-fpc-spectrum-analyzer_63493-542324.html
DaJMasta:
Signal analyzers are meant for analysis of the baseband extracted from the RF carrier, so they have additional hardware/software to have this functionality.  Often spectrum analyzers will have a limited demodulation capability (like AM/FM/PSK as audio output) and some will have an IF output for external analysis, but a signal analyzers will be able to decode more signals with more bandwidth and will give you more measurements of the modulation used.

Of course, there's a lot of variety on both sides, but generally, a signal analyzer is a spectrum analyzers with additional capability for analyzing the modulation used in the incoming signal.
tv84:

--- Quote from: 2X on June 04, 2024, 09:49:09 pm ---The Rohde & Schwarz signal and spectrum analyzer portfolio
https://www.rohde-schwarz.com/products/test-and-measurement/signal-and-spectrum-analyzers_63665.html

--- End quote ---

Precisely in that page, R&S describes the characteristics of both.
G0HZU:
There's probably a bit more to the signal analyser definition than the VSA capability it offers.

I think that to fully qualify as a spectrum analyser, the instrument should have the design integrity to always achieve a certain amount of spurious free dynamic range (SFDR) no matter how it is configured with its various options. This makes it fit for the purpose of 'spurious free spectrum analysis'. The SFDR includes spurious responses such as IF and image responses.

I don't think a signal analyser has to meet this global SFDR requirement. A signal analyser can be arranged to significantly compromise its spurious free dynamic range (eg it can compromise its IF and image rejection) in order to achieve a wider analysis bandwidth.

Once the SFDR is heavily compromised in favour of the analysis bandwidth, I don't think the instrument can qualify as a valid spectrum analyser because it can also be prone to displaying lots of misleading spurious responses from out of band signals. A signal analyser is usually at its very best analysing signals that fall within its analysis bandwidth. It probably won't be very good at rejecting signals that fall well outside its analysis bandwidth when it is set to its widest analysis bandwidth.

The other category is RTSA or real time spectrum analyser. Tektronix produced a series of RTSAs about 15 years ago including the RSA3408A (36MHz real time BW) and RSA6114A (110MHz real time bandwidth). These instruments could achieve quite good SFDR and so, in my opinion, they can still be classified as a spectrum analyser.

The Agilent/Keysight PXA, MXA and EXA signal analysers can't always achieve a decent SFDR when set to the widest analysis bandwidth. So one could argue they no longer meet the basic SFDR requirement for a spectrum analyser when set to the widest analysis bandwidth.

Obviously, the manufacturer will not be keen to draw attention to this SFDR limitation of a wideband signal analyser when it is compared to a spectrum analyser. So you are unlikely to find this stuff described in the marketing literature. You would have to study the datasheet and work it out for yourself...

pdenisowski:
To be honest, I refer to them all as "spectrum analyzers" (well, actually just "spec ans") and pretty much every person I work with on that team also just calls them "spectrum analyzers" 

The FAQ on our webpage is how I would make distinction if I had to, but we have several instruments (FPL, FSVR) that can analyze and demodulate vector signals (cellular, Wi-Fi, etc.) but still have "spectrum analyzer" on the label.  And our flagship analyzer, the FSW, has "Signal and Spectrum Analyzer" on the front :)

So if we use the definition in the FAQ, the FPC would be a spectrum analyzer because it doesn't analyze or demodulate vector signals.  That's pretty much all there is to the name.

Incidentally, I have an FPC in my office right now, so please also feel free to ask me any questions you might have.  I've already made about a half dozen videos on the FPC (see the R&S YouTube channel) and am working on some new videos this week showing how to use the FPC1500 for network analysis (that model has an integrated tracking generator and VSWR bridge).

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