SA's: Anritsu MS2711/12E vs R&S FSH3 vs Agilent N9340B: Input wanted - Page 1
Forum section: electronics / testgear

author: videobruce
author_rank: Frequent Contributor
timestamp: May 23, 2014, 09:37:02 pm
content: I'm looking at a Spectrum Analyzer to replace one that was sold. This time I'm strongly considering a portable (handheld) one, but not one of those that are the size of a SLM. Most of the time it will be a 'bench' scope, but the ability to use it in the field is a plus. Applications are OTA (over the air) RF monitoring namely TV Broadcast, 2 way radio, WiFi etc.These are what I have looked at (links are for data sheets & user guides);Anritsu MS2711/12E;(the 2712E has 10db lower SSB Phase Noise, 17db more Dynamic Range over the 2711)http://www.anritsu.com/en-US/Downloads/Brochures-Datasheets-and-Catalogs/datasheet/DWL8856.aspxhttp://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=6&cad=rja&uact=8&ved=0CFIQFjAF&url=http%3A%2F%2Fd3fdwrtpsinh7j.cloudfront.net%2FDocs%2Fdocument%2F10580-00328D.pdf&ei=_d2BU7m4IMe3sATTmoCwBA&usg=AFQjCNFESnowFs0zymlL5QPD96M5mY2M_A&bvm=bv.67720277,d.cWcAgilent N9340B;http://www.home.agilent.com/agilent/redirector.jspx?action=ref&cname=AGILENT_EDITORIAL&ckey=1398700&lc=eng&cc=US&nfr=-33812.761701.00http://www.home.agilent.com/agilent/redirector.jspx?action=ref&cname=AGILENT_EDITORIAL&ckey=1460384&lc=eng&cc=US&nfr=-33812.761701.00Rohde & Schwarz FSH3;(discontinued)http://cdn.rohde-schwarz.com/dl_downloads/dl_common_library/dl_brochures_and_datasheets/pdf_1/FSH_dat_sw_en_5214-0482-22_V1700.pdfhttp://cdn.rohde-schwarz.com/dl_downloads/dl_common_library/dl_manuals/gb_1/f/fsh_1/archive_27/FSH_Operating_Manual_15.pdfRohde & Schwarz FSH4;http://cdn.rohde-schwarz.com/dl_downloads/dl_common_library/dl_brochures_and_datasheets/pdf_1/FSH_dat_sw_en_5214-0482-22_V1700.pdfhttp://www.rohde-schwarz.com/en/manual/r-s-fsh4-8-13-20-operating-manual-manuals-gb1_78701-29159.htmlRigol DSA-1030A;(you need to register to get the pdf's, no known spam advertising in doing so)http://beyondmeasure.rigoltech.com/acton/attachment/1579/f-0026/0/-/-/-/-/file.pdfhttp://www.rigolna.com/download/501G00000001O4TIAU/Dedicated thread here;https://www.eevblog.com/forum/testgear/(video)-rigol-dsa1030a-tg3-spectrum-analyzer-review-and-experiments/msg164431/#msg164431The necessities are;tracking generator,preamp,high input level,large display,fast sweep speeds (preferably down to 20ms),easy to use; conventional menu structure..Notable differences I have found from looking over the spec sheets and user manuals are;MS2711/12; slow 100 ms sweep, very large display (800x600), 5 minute warmup, (preamp is standard in the 2712), major changes from the 'D' version, this should of been given a different numberN9340B; 10ms sweep, somewhat higher input level, medium sized display, backlit keys (somewhat unusual), 30 minute warmup, widely availableFSH3; smaller, very low resolution display (320x240), preamp & attn are linked together and automatically cut in and out depending on the reference level set (no apparent override), unconventional 'handle' that 'hangs out' the rear of the top of the case (I see no purpose for this), very odd RS-232-C "optical" PC interface (never heard of that), unconventional UI is reported by many as user unfriendly.FSH4; slightly larger, far better display (640x480), better specs, additional ports, a ton of options & more expensive of course (no surprise here). UI appears to be the same. All the info bars are horizontal, none are along the sidesRigol DSA-1030A; There isn't a hell of a lot of price difference between the 1030 and the 1030A considering the 8db improvement in phase noise & the 10db improvement in DANL. Doesn't seem worth bothering with the 1030, lower input level. It's too bad these have such a price difference over the baby brother; 815.There are also Hameg (now owned by R&S) HMS-X which is the HMS-3010 and the Atten/Gratten GS4063. Both are AC only, selling around $5800 w/TG & Preamp. I was never that impressed with Atten, being an no name company. Hameg (in the US) is not a widely known unlike in Europe. They have little presence in the US. That may change depending on what R&S does with the name.(added R&S FSH4 & the Rigol DSA-1030A)

author: videobruce
author_rank: Frequent Contributor
timestamp: May 23, 2014, 09:55:25 pm
content: From those two small players, here are some links;Hameg HMS-X/HMS 3010;http://www.hameg.com/0.722.0.htmlhttp://www.hameg.com/manuals.0.html?&no_cache=1&tx_hmdownloads_pi1=download&tx_hmdownloads_pi1=7350https://www.eevblog.com/forum/testgear/hameg-rs-new-hms-x-3ghz-upgradeable-spectrum-analyzer-announced/Atten/Gratten GA4063;http://www.atten.eu/ga4063-3ghz-spectrum-analyzer.html?___store=usa&___from_store=germanhttp://www.saelig.com/TSTEQSA/TSTEQSA007.htmhttp://www.saelig.com/supplier/atten/GA4063_user_manual.pdfThe HMS-X is a re-badged HMS 3010 with a different option setup. There is a current trend to include ALL hardware (and firmware/software) in these devices with the 'options' locked out unless you purchase a separate 'key'. This includes options such as a preamp and the expensive tracking generator that can sell for over $2,000 on the higher end models. I found this hard to believe at first, but I guess it makes some sense. All one has to do is contact the importer or manufacture and pay for the 'key'. From what I understand with some (at least), the key is tied to the specific unit which means one can pas a 'key' to another owner.It just gets me, hundreds or thousands of dollars worth of options are just siting there if not activated. Think of buying a motor vehicle with air conditioning or one with four wheel drive that are not enabled because the option was not purchased.Below, attached is a spread sheet for a number of these SA's.(There probably are a few errors in some of the details.)

author: videobruce
author_rank: Frequent Contributor
timestamp: May 24, 2014, 06:42:32 pm
content: Prices used for the three are between $4200 & $8,000 depending on source.Separate questions;Is DANL the most important spec overall for a SA?How does the reference level affect the DANL spec? 20, 30, 50 & 70 dBm levels were used in the specs of these three SA's.Can I assume the narrower the RBW, the better the DANL result will be?

author: Mr Simpleton
author_rank: Unknown
timestamp: May 24, 2014, 06:53:52 pm
content: We have several FSH3 at the salt mine, but I hate them! Talk about user unfriendlinessThanks but No thanks!The newer FSH8? may be improved, hard to get it any worse thoughThe Agilent, have yet to try, but someone reported software bugs...As for the Anritsu, never tried SA's from Anritsu, only microwave sweepers/sg.I have an old HP 8561B that weights a ton but is almost movable, and somewhat resembles the venerable 8568 which is my reference for user interface. If I really need portability I pack my small Signal Hound SA44B, which gets power from computer USB-port and is as large as a box of matches. Still do work but have its limitations, lacking fast sweep is the most serious one.Not an easy choice, but if you do need the portability and performance, I would look closer at the Agilent.

author: G0HZU
author_rank: Super Contributor
timestamp: May 24, 2014, 07:12:25 pm
content: At work we have the Anritsu 2711D with colour display and several of the FSH3 analysers.I've never actually used the FSH3 because they are always in use on field trials (across the World) but I have used the 2711D plenty of times.Basically, the Anritsu 2711D is very pretty to look at and it does the job (i.e. the odd field trial) but it has a really annoying user interface. It's very sluggish and gives a loud beep on button presses. The user interface is NOT written by someone who is a regular SA user because the function/menu selections are annoyingly 'different' to other analysers. eg some commonly used functions are hidden behind a few beepy and slow button pushes. The screen is a bit slow to refresh as well.But if you can live with the beeps and clunky interface it is a nice little portable analyser as long as you don't expect too much from it in terms of spurious free dynamic range. It charges up fairly quickly and is very portable (but then so is the FSH3)However, the 2711 series is quite old and I think I would want to have a very close look at the Agilent analyser as it is more modern and has lower RBW and a fairly decent dynamic range. But I can't actually recommend it because I've never used one.

author: KJDS
author_rank: Super Contributor
timestamp: May 24, 2014, 07:13:50 pm
content: There are many things important on a spec ana, the details of which will vary depending on what you are using them for.For me, the most important is the spurious free dynamic range. The first mixer will generate not only the desired IF signal, which is then further downconverted and passed though the RBW filters, but that mixer also generates some spurious signals from undesired mixing products. You don't ever want to see undesired products on the screen.Imagine a 1GHz spec ana, with a first IF of 1400MHz. There will be spurious generated at 1400MHz from a variety of inputs, including any signal at 1400MHz that hasn't been suitably attenuated by the input filter. If you're looking for a low level off air signal, then a TV transmitter at 500MHz mixing with the local cell tower at 900MHz is just one example of a potential problem. Using a pre-amp tends to exacerbate this. It also makes the input return loss worse so amplitude accuracy is reduced. It doesn't matter if you're only looking at a narrow span at 150MHz, those interfering signals are still present at the input and will get to the first mixer.Narrower RBW will reduce the DANL, however it can also reduce the apparent level of a some modulated signals. CDMA is especially prone to this.I have only used the FSH, however I've familiar enough with Anritsu and Agilent gear to know that mostly I prefer an Agilent user interface. Anritsu may make sense to the Japanese, and R&S to the Germans, but I don't find either of them intuitive. Having said that, once you get used to an instrument it is rarely an issue.If you're after something small and portable but with professional quality, have a look at the Anritsu sitemaster range. I do have a Signal Hound but I wouldn't want to rely on it for anything accurate.

author: G0HZU
author_rank: Super Contributor
timestamp: May 24, 2014, 07:28:32 pm
content: I just had a look at the 2711E and it looks to a new design... Much better than the old 2711D !I would probably have it at the top of the list ahead of the Agilent because the spec looks pretty good! I just hope the user interface is better than the 2711D

author: videobruce
author_rank: Frequent Contributor
timestamp: May 24, 2014, 07:54:42 pm
content: Mr Simpleton;Can you be more specific regarding the problems with the R&S FSH series? What/where is the unfriendliness about them? Other than that, how about overall performance?The reported 'software bugs' with the Agilent, is it these models or something older? Any specifics? Why Agilent over Anritsu?G0HZU;The current 'E' series looks very different from the older 'D' series. Clearly the D series I would not consider based on what you posted, but I would like to think the newer model would of addressed all, or at least most of that. I will have to compare the specs of the E with the D, but from what is shown for the E, it's kinda hard to believe there is a problem with it's dynamic range.KJDS;Is the "Input related spurious response" the same as "spurious free dynamic range"?The 9340 is -70 dBc at -40dBm input,the 2711/2712 is -75dBc at -40dBm input andthe FSH is -70 dBc at 30dBm input

author: videobruce
author_rank: Frequent Contributor
timestamp: May 24, 2014, 09:29:18 pm
content: KJDS;The 332E would be the one, but it is out of my price range due to all the specialized functions. It looks more suited for CATV and Cell site installers. There is a TG option, but there is no preamp. The screens are the same and so is the menu structure as far as I can tell. Also, the specs seem similar.

author: Mr Simpleton
author_rank: Unknown
timestamp: May 24, 2014, 09:38:28 pm
content: I find it hard to find functions in the menus, beeing used to HP/Agilent... Things like peak finding. Still people uses FSH3 and seems happy, maybe it's me that's wrongWell the LCD display is noting to write home about, and the optical RS-232 do work but is pretty "clunky", and you do need the R&S software to capture sceen. Think the RBW is rather poor for an instrument costing this much! And the LCD is not really state of the art eitherWe do use them when out in the field, where portability is prime, but each and every time I have to use the FSH3 I feel... "not happy"Still cannot say there is anything seriously wrong with it though.As for s/w bugs and Agilent.. trying to remember where I saw this, but it may just be rumours so better keep my mouth shut, but AFAIK the Fieldfox is a lot newer then the R&S so should have better LCD and processor power... you may look at some newer R&S FSH4/8 to compare with the Agilent.

author: videobruce
author_rank: Frequent Contributor
timestamp: May 24, 2014, 10:25:44 pm
content: Assuming you are referring to the R&S FHS regarding the menu. I have been trying to go through the owners manual. The menu structure is odd, surely not the norm.That display is the worst of the three. Anritsu being the best, but the slow 100ms sweep is a problem, especially in this price range.

author: DJ
author_rank: Unknown
timestamp: May 25, 2014, 08:29:15 pm
content: Check with agilentused on that big auction site for a good deal on the N934xB/C series.If price is paramount, a signalhound may also be worth a look. They also sell on fl3abay under dodgeballblue, iirc.

author: videobruce
author_rank: Frequent Contributor
timestamp: May 26, 2014, 12:46:06 am
content: I have been to their Malaysia site, but I have my reservations buying from overseas, but I'm not ruling it out yet.That Signalhound is out of the question. Price isn't that paramount.

author: DJ
author_rank: Unknown
timestamp: May 26, 2014, 01:50:37 pm
content: No worries with agilentused - 100% positive feedback. They will also configure options to suit.Some are sw (can add at any point), some are hw (tracking gen comes to mind) and are not user installable, AFAIK.

author: videobruce
author_rank: Frequent Contributor
timestamp: May 26, 2014, 09:14:41 pm
content: Too bad R&S and/or Anritsu don't have similar outlets.Over 300 views and only a handful of replies?? All you others have no input here?

author: KJDS
author_rank: Super Contributor
timestamp: May 26, 2014, 10:14:38 pm
content: Quote from: videobruce on May 26, 2014, 09:14:41 pmThat's about average for the forum. There won't be that many people on here that have used those equipments, but plenty of people that want to read and learn.

author: videobruce
author_rank: Frequent Contributor
timestamp: May 27, 2014, 10:37:35 am
content: I'm glad I can offer a service.

author: 1design
author_rank: Regular Contributor
timestamp: May 27, 2014, 12:40:24 pm
content: I can't compare them but I do own the N9340B with preamp and TG. I must say I'm quite satisfied with the unit for the simple tasks I use it for which is similar to what you mentioned in your first post. Only the buttons are a bit harsh as they are meant to be used in the field, maybe with gloves so you need to press them harder than normal lab grade equipment and it becomes a bit annoying with time. As performance goes it is up to spec and nothing is given for free.As far as the FSH3 goes...I have used it at my previous job and it was a nightmare regarding the screen and user interface. I wouldn't advice it for everyday bench use.

author: videobruce
author_rank: Frequent Contributor
timestamp: May 27, 2014, 08:27:53 pm
content: Wow, that R&S is that bad? Thanks for additional the input. Anyone else on the tough button presses??What bothers me for each model;R&S: Crappy small display and ridiculously low resolution especially, at this price point. Too 'portable' for what I would prefer. This will be a bench scope most of the time.Agilent: The 'toy' like look with those blue, curved handles on each side. It looks like a oversized video game. Surely not something that commands this price tag. I know it sounds silly, but I like a professional piece of equipment to look the part.Anritsu: The number one issue is the very slow sweep speed of 100ms. The other two scopes have 10 or 20ms. This is the most expensive of the three (on the used market), but has the slowest sweep. On the other hand, it has the largest and highest resolution display by far. And also has the looks to match. Something that would look spot on on the bench.

author: G0HZU
author_rank: Super Contributor
timestamp: May 28, 2014, 10:18:00 pm
content: Note: The phase noise spec on the Anritsu is pretty awful at 1MHz offset and suggests that the synthesiser has been designed with a very wide loop bandwidth.So even the Rigol 815 will totally outclass it for far out phase noise on something like a 2MHz span with 10kHz RBW. If the phase noise spec really is as bad as the specsheet suggests then it is one of the noisiest analysers I've ever seen for phase noise at a 1MHz offset.But I guess you have to make allowances for the fact it is a portable analyser and not something meant for even semi serious bench use. Are you sure you want a portable analyser? The primary use for this analyser is to stick a little aerial on it and turn on the preamp and then walk around a field or test site somewhere and look at small to medium signal levels. That's what it is optimised for and I doubt the phase noise limitation would be a problem very often in that scenario.

author: videobruce
author_rank: Frequent Contributor
timestamp: May 29, 2014, 01:12:12 am
content: I assume you are referring to the 2711 vs the 2712?SSB Phase noise at 1 GHz;'11' is -105dBc/Hz, -111 dBc/Hz typical @ 1MHz offset'12' is -115 dBc/Hz, -121dBc/Hz typical @ 1MHz offsetFor comparision, their step up is the 2720, 9GHz bandwidth model;-118 dBc/Hz, -123 dBc/HzSince you mentioned Rigol; their 1030A model (their best), the numbers are;-110 dBc/Hz 1 MHz offset (but at 500 MHz)Their DANL is between 12-16 dBm lower

author: G0HZU
author_rank: Super Contributor
timestamp: May 29, 2014, 11:57:38 pm
content: All those specs look a bit poor...However, I've seen a few screenshots of the Rigol 1030 on 600MHz and the phase noise at 500kHz offset looks to be in the ballpark of -118dBc/Hz.Maybe the spec sheet quotes for some special case. eg maybe the analyser PLL switches in a wider loop bandwidth on very big sweeps to speed up the lock time. So they quote phase noise for this worst case figure?If so, then I would expect the phase noise to be way better than -105dBc/Hz at 1MHz offset on the Anritsu if you set it to 'just' a 2MHz span and measured the phase noise at 1MHz away.A decent old school bench analyser would show about -130dBc/Hz at 1MHz offset at 1GHz. A good one would get closer to -140dBc/Hz. Maybe you could ask Anritsu for a plot of phase noise at 1GHz on a 2MHz span? I reckon (hope?) it won't be as bad as -105dBc/Hz at a 1MHz offset

author: videobruce
author_rank: Frequent Contributor
timestamp: May 30, 2014, 10:41:23 am
content: What would you consider good??

author: G0HZU
author_rank: Super Contributor
timestamp: May 30, 2014, 12:52:47 pm
content: Well I guess a lot depends on the intended application...If you definitely wanted a portable analyser (to do portable analysing of the spectrum in a field somewhere) then I guess I wouldn't be telling you to watch out for the phase noiseThis is because 'good phase noise' is defined by the latest portable offerings from Anritsu, Agilent and R&S. Or in other words you are stuck with whatever design compromises they need to factor into the design to make it so small and portable with good battery life etc. Phase noise is just one thing they have to compromise on.But you said you also want to use it as a bench analyser and I think you might find the performance to be a bit borderline for bench use.I dug out the MS2711D at work today and measured the phase noise at 1GHz and also 101MHz.1GHz10kHz offset -73dBc/Hz20kHz offset -78dBc/Hz50kHz offset -87dBc/Hz100kHz offset -93dBc/Hz500kHz offset -108dBc/Hz1MHz offset -111dBc/Hz101MHz10kHz offset -76dBc/Hz20kHz offset -79dBc/Hz50kHz offset -88.5dBc/Hz100kHz offset -94.5dBc/Hz500kHz offset -110dBc/Hz1MHz offset -114dBc/Hz

author: G0HZU
author_rank: Super Contributor
timestamp: May 30, 2014, 01:04:30 pm
content: I also (very casually) measured a fairly decent 'semi portable' Agilent spectrum analyser the 26GHz 8563EC as there was one free on the next workbench.1GHz10kHz offset -114dBc/Hz20kHz offset -115dBc/Hz50kHz offset -117dBc/Hz100kHz offset -124dBc/Hz500kHz offset -131dBc/Hz1MHz offset -134dBc/HzThis analyser is very heavy. I'm guessing it's nearly 20kg and is several times larger than the 2711D and it costs a lot of money when new.So it isn't really a fair comparison but you can see what you get towards the other end of the performance scale if you go for a semi portable analyser that is primarily aimed at bench use.It really is up to you to decide if the phase noise is an issue. I can describe how it will affect the everyday performance if that would help? Phase noise might not be a problem for your intended usage?

author: ivaylo
author_rank: Frequent Contributor
timestamp: May 30, 2014, 05:27:46 pm
content: QuoteDo you mind listing models (any manufacturer) which fit this characteristic?

author: Mr Simpleton
author_rank: Unknown
timestamp: May 30, 2014, 07:29:13 pm
content: HP 8560 seriesHP 8566/68 seriesAll have good phase noise and are a pleasure to use

author: videobruce
author_rank: Frequent Contributor
timestamp: May 30, 2014, 09:46:51 pm
content: You forgot to add, they are 30 year old boat anchors & power hogs with CRT's..QuoteHow much was that when new $40k (US)??

author: 1design
author_rank: Regular Contributor
timestamp: May 30, 2014, 10:07:17 pm
content: Actually I missed what are you going to use this for, as old SA do not support so many measurements as the new ones do, especially regarding digital demodulation, things like burst demodulation, EVM and other constellation data, gated sweeps, SEM, ACP, etc. Take this into consideration when choosing such an instrument. I really like the channel power, occupied BW etc. for digitally modulated signals; it saves me time over hand calculations.BR

author: videobruce
author_rank: Frequent Contributor
timestamp: May 30, 2014, 10:16:32 pm
content: OTA broadcast, mostly TV. Also 2-way communications & WiFi. No cellular. Some RF sniffing.

author: videobruce
author_rank: Frequent Contributor
timestamp: May 30, 2014, 10:22:57 pm
content: G0HZU;I was only looking at the 1 MHz offset since that was the most common spec. I now see, the 10kHz offset really drops that number way down on some.Regarding this phase noise, looking back over the specs of a few of these the Rigols (815 & the 1020) are -80dBc/Hz at a 10khz offset. The 1030a is -88dBcThe 9340E is -87 dBc, but the 2712E is -100dBc (-110dBc typical).That 2711D is a much older design.What applications would a lower phase noise benefit the most. And what applications would it benefit the least?

author: G0HZU
author_rank: Super Contributor
timestamp: May 30, 2014, 11:37:24 pm
content: High phase noise masks weak signals (it raises the noise floor) if there is one 'big' signal on the screen.So having low phase noise is really useful if you want to be able to look at small signals that are very close to big ones.See the image below for an extreme case. The black trace is an old school (huge/heavy) bench analyser from Japan from 25-30 years ago. The signal going into the analyser is from a low noise sig gen at 1GHz. The span is 2MHz and the RBW is 10kHz. The blue trace is my handwritten overlay of what you would see on a MS2711D on the same span with the same RBW because it has such high phase noise.You can see how the little portable analyser will not be able to display small signals that are close to the carrier because they are covered by all that noise.However, don't get too worried because for portable monitoring on a small aerial you are unlikely to be seeing such a huge variation of signals and the little portable analyser will not have huge signals masking the performance like this. So for typical portable use then don't worry...But for bench use you might want to look for tiny spurious signals from a transmitter and the little portable analyser will struggle a bit. You can use narrower spans and lower RBW settings to overcome some of this but it means the measurements aren't as quick and easy as with a decent bench analyser.

author: videobruce
author_rank: Frequent Contributor
timestamp: May 31, 2014, 02:43:55 am
content: QuoteUnless it is connected to a outside antenna which it can and will be.That is exactly what I have had a problem with. Overload from nearby TV xmitters (7 miles away). It raises the noise floor depending on settings.Then that is a biggie, at least for me.Then how does DANL come into play?

author: The Electrician
author_rank: Frequent Contributor
timestamp: May 31, 2014, 04:33:14 am
content: Here are images showing the performance of a Rohde&Schwarz FSH4, and an Anritsu MS2713BI applied a -10dBM, 1 GHz signal from an old Agilent 8657B siggen.The SA settings were 10 kHz RBW, 1 kHz VBW, 5 MHz span, preamp off, attenuator off.You can see that the Anritsu is overloaded.The sweep speeds are definitely slower than a bench SA, but they seem reasonable to me.I think that as time goes on and DSP processors get faster and lower power consumption, we'll see faster sweep speeds. I'm impressed at just how long the battery life is on these units--several hours typically.

author: 1design
author_rank: Regular Contributor
timestamp: May 31, 2014, 07:46:54 am
content: Phase noise is important when looking at closely spaced CW or narrowband signals, for wideband signals you must also look for TOI distortion, which will come into account as soon as there is more than one tone present. This is a very practical parameter that informs you about the linearity of you SA. For example, broadcast stations used in uW backhaul might have 50-60dBc IMD3, so you need a very good SA to measure such systems as they use adaptive predistortion. On the other hand, WIFI routers have an IMD3 of only about 20-30dBc which is easily visible by any SA. I will try to take some pictures next week to help you see the difference, like The Electrician did.BR

author: videobruce
author_rank: Frequent Contributor
timestamp: May 31, 2014, 12:39:32 pm
content: First off, I would like to thank the all the members, especially the recent additions. The information is very welcome.The Electrician; Very interesting. You wouldn't happen to have a Rigol DSA1030A (or a 1030) and/or a Agilent N9340B would you?? Of course you know this is throwing a wrench into the works.One thing you have to admit, the 27xx series has a killer display, the exact opposite of the FSH3.

author: G0HZU
author_rank: Super Contributor
timestamp: May 31, 2014, 12:45:52 pm
content: I had a go at overlaying the phase noise profiles of all the analysers mentioned.The red trace is the FSH4 based on the plot from the Electrician.The green trace is the typical phase noise of the 2711E according to the datasheet and the yellow trace is the typical phase noise of the 2713E according to the datasheet.You can see that the 2711E is quite noisy compared to the others (apart from the older 2711D in blue)I think I would be happy to accept the phase noise performance of the FSH4 and the MS2713E for portable use but the 2711E (green) looks too noisy. However, maybe it will be better than the green trace when it is measured on a real unit?

author: G0HZU
author_rank: Super Contributor
timestamp: May 31, 2014, 01:14:16 pm
content: The other thing that looks weak on the Anritsu is the spec for harmonic distortion. It seems to get weaker with lower frequencies.It states 0dB attenuation and a -30dBm tone and a typical internal harmonic would be -60dBc. Again, a decent bench analyser will give a typical result that is much better than this.A 'reasonable' bench analyser will have a 2HI of about +50dBm at the mixer so for a -30dBm signal the harmonic would be -80dBc. A strong bench analyser will have a 2HI closer to +70dBm so the harmonic would be -100dBc for the above test.Usually, you are supposed to allow a 15-20dB margin on the internal harmonic level if you want to make a reasonably accurate measurement of a second harmonic level. Otherwise the internally generated harmonic can cause high measurement uncertainty. If you allow an 18dB margin then the uncertainty falls to about 1dB. So the 2711E would be good to -42dBc if you measured with a -30dBm fundamental signal at the mixer and wanted to keep the uncertainty down near 1dB.This would be OK for typical ham radio use because the harmonic rejection requirements are very sloppy on the ham bands but it's not so good if you wanted to measure something with a decent spec like -65dBc. In this case you would have to use extra attenuation on the Anritsu and use a narrower span and RBW to claw back the required range.None of the above really matters for portable use but if you want to use the analyser on a bench for more serious harmonic rejection testing you might hit a few problems

author: The Electrician
author_rank: Frequent Contributor
timestamp: May 31, 2014, 04:07:11 pm
content: Quote from: videobruce on May 31, 2014, 12:39:32 pmSorry, but I don't have access to a Rigol or Agilent.I also haven't ever had access to a R&S FSH3, but the FSH4 is a newer unit, and I would expect better performance all around.The FSH4 display has good resolution, but it's not as bright as the Anritsu. The Anritsu is "majorly" bright (as my young nephew would say).Another thing I notice is that the numbers for sweeps/second on the Anritsu don't make sense to me. I set it up to look at a local TV station (a digital signal here in the U.S.) at around 600 MHz. Using a 5 MHz span and 10 kHz RBW, the instrument reported a sweep time of 900 mS, but the update rate on the display is much faster than that; I would estimate about 50 mS. I see this behavior constantly; the unit is much faster than it indicates. They must mean something different than what I would expect by the term "sweep time". The FSH4 doesn't behave like this. It reports a sweep time that is consistent with what you see on the display.Both units exhibit the behavior you would expect. For wide spans and narrow RBW, it gets slow.For other settings, I've seen the FSH4 report sweep times as low as 22 mS, and for similar settings the apparent performance of the Anritsu is just as fast even though it reports a much longer time. I can't explain this.R&S makes another "semi" portable SA, the FSL3:http://www.rohde-schwarz.us/en/products/test_and_measurement/aerospace_and_defense/test_and_measurement_instruments/spectrum_signal_analyzers/FSL.htmlwhich I have occasionally had access to, and I've seen that unit exhibit sweep times of as low as 2.5 mS! It has a battery option, too.The N9340B looks good; maybe you can get the Agilent rep to show you one. Their spec of .1 second for a full 3 GHz sweep (RBW unknown) is outrageously fast!The Anritsu, for a 3 GHz full sweep, 3 MHz RBW, reports 14.785 seconds, but visually I estimate it's taking about 1.5 seconds.

author: videobruce
author_rank: Frequent Contributor
timestamp: May 31, 2014, 06:37:58 pm
content: The Electrician;Could you comment on those questions in those two screen shots of yours in my previous post?I'll look into the FSL3.

author: The Electrician
author_rank: Frequent Contributor
timestamp: May 31, 2014, 07:41:36 pm
content: Sorry. I didn't realize you had annotated the images with questions; I can't see that in the thumbnails.WRT to the Anritsu, when I said it was overloaded, I was basing that on the message that says "ADC Over Range..." I assume that the red colored portion of the spectrum might be affected by the overload, and by coloring that portion red the analyzer is warning us that perhaps that portion is not trustworthy.About the FSH4, I guess the FSH4 has a different PLL characteristic in the reference oscillator circuit, leading to a different shape and rolloff rate in the phase noise. It looks like Anritsu did a somewhat better job with their design.

author: videobruce
author_rank: Frequent Contributor
timestamp: May 31, 2014, 07:46:25 pm
content: How do you get the images embedded in the post like you did?Regarding the pattern on from the Anritsu, those 'sidebands' if you can call them that, could it be since there is a overload situation, the scope reduced them so the entire signal would fit on the screen? (Hope that made sense)

author: The Electrician
author_rank: Frequent Contributor
timestamp: May 31, 2014, 08:12:58 pm
content: Quote from: videobruce on May 31, 2014, 07:46:25 pmI'm not sure how you're supposed to do it, but what I do is attach them and Post, leading to thumbnails like you have.Now you have to go back and modify your post to add each image. Right click on one of the thumbnails and cntrl/C to capture the link. Then click in the upper right of the post on "Modify". Then, where you want the image, type "[i.m.g]", paste the link address, then type "[/i.m.g]". Finally, "Save". Repeat for each thumbnail. Leave out the decimal points in [i.m.g]; I had to put them in to be able to show the img command.Quote from: videobruce on May 31, 2014, 07:46:25 pmI'm not sure about that. On both analyzers, as I reduced the input, the "hump" of phase noise gradually reduced and one was left with a normal looking spectral display. There didn't appear to be anything happening like you describe.

author: The Electrician
author_rank: Frequent Contributor
timestamp: May 31, 2014, 08:17:18 pm
content: OMG!!! Have a look at the movie on this page:http://www.rohde-schwarz.us/en/products/test_and_measurement/aerospace_and_defense/test_and_measurement_instruments/spectrum_signal_analyzers/FSW.htmlPhase noise of -137dBc at 10 kHz offset (1 GHz carrier)!!You get what you pay for.

author: G0HZU
author_rank: Super Contributor
timestamp: May 31, 2014, 08:50:38 pm
content: QuoteGoing a bit off topic here, but you have to be wary of modern (marketing) spec claims for phase noise at 10kHz offset. The Agilent PXA can get close to this figure... eg it can get to something like -133dBc/Hz but it does this by pushing out the loop bandwidth to something like 700kHzIt is a special type of phase noise cleanup mode on narrow spans,So you get -133dBc/Hz at 10kHz (because of the high noise cleanup inside the loop BW) but the phase noise at 600kHz offset will be -120dBc/Hz. But you don't easily spot this penalty because this increased hump of noise up at 600kHz is off the screen. The Agilent marketing bods will make this downside less obvious in the marketing specsheetsWhen you select a wider span it will turn this wide loop BW mode off and this cleans up the phase noise at 600kHz offset to be more like -140dBc/Hz. The phase noise at 10kHz in this 'normal' mode will be about -110dBc/Hz.I strongly suspect that R&S are resorting to the same wide loop BW trick with the FSW.

author: Mr Simpleton
author_rank: Unknown
timestamp: May 31, 2014, 09:13:20 pm
content: I may have access to FSH3 and FSL if you want/need some tests done!Try to see if there is any Agilent stuff around, but doubt it... Mostly old heavy HP, as carry around has not been a primary ting.I told you how I feel about the FSH3, but sure can do some screen captures if needed, and if I can find the RS232-optical interface.I think newer S/A are overpriced... new hardware should bring price down and performance up... now with the Rigol they seem to use the integrated PLL/VCO from Agilent, and this gives mediocre p/n. Pity, they should have spent some more developement on the LO.Have you had a look at the Hameg HMS? Sits in between R&S and Rigol both in performance and price, and now owned by R&S

author: G0HZU
author_rank: Super Contributor
timestamp: May 31, 2014, 10:25:32 pm
content: Dunno if this helps but I quickly set up a demo of Agilent's phase noise enhancing method by applying it to a PLL board I have here that I can control/program for different loop characteristics.The plots below are of a single loop PLL running at 1500MHz. In the first plot I've selected a normal loop bandwidth for the PLL on the test board and you can see that the close in phase noise is quite high but it tapers away in a normal fashion.In the second plot I've dynamically altered the PLL loop bandwidth. I've not changed the phase detector frequency, I've just altered the PLL characteristics by reprogramming it for a different loop characteristic. This is all done in software i.e. I don't have to change any components on the PCB to get this change.You can see how I can now claim lower phase noise at a 15kHz offset for my little test board!But the penalty is the hump of noise at a 150kHz offset. The phase noise is now WORSE at 150kHz to get the noise 'better' at 15kHz.Agilent appear to do something like this on the synthesisers in the PXA analyser but the hump of noise is at 600kHz offset.Anritsu could well be using this trick on the MS2713E because this technique is making its way into lots of test gear. My HP/Agilent ESG 4000D sig gen has this feature as a user control. I can make the close in phase noise look really good but the far out phase noise gets much, much worse...

author: The Electrician
author_rank: Frequent Contributor
timestamp: May 31, 2014, 11:00:10 pm
content: Imagine if the image I posted for the FSH4 were 500 kHz span rather than 5 MHz. See the hump close to the center freq? Looks similar, doesn't it?

author: videobruce
author_rank: Frequent Contributor
timestamp: May 31, 2014, 11:09:20 pm
content: The Electrician;Get a load of the size of that scope and the size of the display!Gotta love looking at pieces of gear worth $50k or so.I thought only the CEA (consumer electronics) were the ones that pull stunts like that.

author: videobruce
author_rank: Frequent Contributor
timestamp: May 31, 2014, 11:18:05 pm
content: QuoteYes, that would be beneficial.Yes, I have ruled out the FSH3, but not the 4, but I'm afraid it is out of my price range. At least they at least went with a 640x480 display. I wish Agilent would redesign the 9340 and get rid of the video game look..QuoteAgreed! Regarding Rigol are you referring to all of their SA's or just the 1030/1030A?.QuoteNo, but anyone have any "vouchers' lying around?Looks like you have to buy the ECM option to get the preamp.

author: G0HZU
author_rank: Super Contributor
timestamp: May 31, 2014, 11:32:48 pm
content: QuoteYes, I suspect they could be selecting a wide loop BW to clean up the phase noise at 10kHz so they can make a nice marketing claim about the phase noise at 10kHz. Also, the wider loop BW will mean the PLL will have a faster retune time. It's probably a better compromise compared to having higher noise close in?See the attached image from Agilent that shows the phase noise optimising modes in their PXA analyser. I've edited out the less relevant traces but you can see the Wide and Narrow loop responses that it swaps between depending on the SPAN setting on the analyser when in non swept mode.You can see that by selecting the wide loop BW mode the phase noise at 10kHz offset is about -133dBc/Hz but the penalty is the huge hump of noise further out at 500-600kHz. It doesn't look quite so significant in the graph because it uses a log frequency scale and the hump appears 'less far out' in frequency terms. But either way, the phase noise has a 12dB peak at about 500kHz and is 20dB worse here compared to the conventional 'narrow' mode.

author: Mr Simpleton
author_rank: Unknown
timestamp: May 31, 2014, 11:33:38 pm
content: Those plots does not behave the way they should!!!!With a narrow loop filter you will see the VCO characteristics, but with the wide band loop filter this will reflect the reference oscillator noise, inside the loop filter, but with the 20log(n) where n is the multiplication. The hump is usually what you have when the filter is not optimized for noise i.e. you could have even wider band, having the cross over frequency so wide that the noise hump dissapear.In the two plots I do not see VCO phase noise beeing similiar outside the filter, hence some weardiness is going on

author: G0HZU
author_rank: Super Contributor
timestamp: May 31, 2014, 11:39:26 pm
content: Quote from: Mr Simpleton on May 31, 2014, 11:33:38 pmAll I do in my plots is to dynamically alter the phase detector gain by changing the register contents in the PLL chip (i.e. it's done in software in the blink of an eye). The hump in the noise will be due to a poor phase margin in the wide mode. I don't have much control over this via software...I don't actually know what Agilent do with the PXA to get the Wide and Narrow modes but you can see they get similar results with the benefit of the 'close in cleanup' bu the penalty of the far out 'noise hump' when in wide mode.

author: Mr Simpleton
author_rank: Unknown
timestamp: May 31, 2014, 11:39:32 pm
content: I bet most modern frequency synths are using quite wide loop filter and use fractional N divisor and/or a DDS for reference. This allows for wide loop filter and low noise multiplication inside the filter bw, plus having fine resolution. Drawback may be spurs...

author: Mr Simpleton
author_rank: Unknown
timestamp: May 31, 2014, 11:43:38 pm
content: Yup, I see the plots but as you say, have no clue on what magic sauce Agilent is using. The VCO do show a lot less noise when having the narrow loop filter, and if you say the only change is the phase detector gain I'm lost!

author: G0HZU
author_rank: Super Contributor
timestamp: June 01, 2014, 12:56:30 am
content: I don't know what Agilent do but the method I used in my quick and dirty demo is nothing special or new or 'magic'...If it helps put your mind at rest, when I simulate my PLL I get exactly the same results as my previous demo plots when I change the phase detector current. The noise at 15kHz improves by about 15dB in the wide mode but there is a peaky hump in the noise at about 150kHz offset as the phase margin reduces a lot in the wide mode.I think what may be confusing you is that the free running phase noise of the VCO is actually fairly similar to the narrow plot. The wide mode is a bit nasty to the VCO at 150kHz and adds extra noise. i.e. the wide mode totally ruins the VCO noise out at 150kHz because of the wide loop BW and the peaking in the noise at 150kHz due to the poor phase margin in the loop. But the benefit is more cleanup down at 15kHz in this mode. If you look at it this way it will make more sense to you.

author: Mr Simpleton
author_rank: Unknown
timestamp: June 01, 2014, 03:45:54 pm
content: What is the loop filter cutoff frequency? Is the noise hump outisde or inside the "wide loop filter"?Guess I do not have a clue on what is going on, as I have only seen these humps with a noisy VCO and too narrow loop filters.IF it is the phase detector generating noise, shouldn't this be filtered out by the LPF? Assuming the hump is outside of loop filer...

author: videobruce
author_rank: Frequent Contributor
timestamp: June 01, 2014, 04:29:00 pm
content: One thing that you guys with access to different SA's with preamps can do is see if and how the Attn & preamp is coupled to the reference level setting. IOW's if the ref. level is dropped (higher sensitivity), will it either turn on the attn, and/or turn off the preamp automatically. Is there a manual/auto selection where that could be turned off?Unfortunately, this seems to be the case now.

author: Mr Simpleton
author_rank: Unknown
timestamp: June 01, 2014, 07:03:46 pm
content: My super simple Signal Hound SA44B do have manual control over the preamp, and it seems fully compensated wrt the ref level.Have to look how the R&S behaves. My HP does not have pre-amp on/off features.

author: G0HZU
author_rank: Super Contributor
timestamp: June 01, 2014, 10:42:09 pm
content: Quote from: Mr Simpleton on June 01, 2014, 03:45:54 pmMaybe this isn't the right thread to be discussing loop theory but I think you are missing something. If I increase the PDet CP current then the loop filter will charge/discharge (up and down in in voltage)quicker. So the loop bandwidth will effectively go UP despite the fact I haven't changed any RC component values in the loop filter. But the phase margin will decrease and this causes the humps in the noise. Result: wider loop bandwidth and peaks in the noise. If I overdid the increase in current then the humps would get huge and peaky as the loop slid towards instabilitySee the attached simulation plots. They agree with my earlier plot quite well. There isn't anything clever happening here... all I did was alter the CP current to get the change in phase noise profile

author: Sailor
author_rank: Regular Contributor
timestamp: June 01, 2014, 11:53:00 pm
content: Quote from: G0HZU on June 01, 2014, 10:42:09 pmIn fact, I have found this thread extremely interesting. Being a non-RF person, seeing some of the insights into SA datasheets vs 'The Truth' is enlightening.GOHZU, what is the PLL board that you are using? Is it a demo, still available, etc? Circuit, code, etc?Now for some uneducated questions/comments...QuoteOkQuoteI don't understand this. Surely the filter bandwidth has not changed? Is it not just that by increasing the gain of the PD it is generating a higher amplitude correction signal (i.e. more 'noise') at frequencies that are closer to the edge of the loop filter? And if that filter has a low damping factor, then that noise gets through, or is even amplified. Is this what you mean by 'effectively go UP' ?Of course, I could be so far wrong that it may be hard to answer, but please try...

author: G0HZU
author_rank: Super Contributor
timestamp: June 02, 2014, 12:42:09 am
content: I'm afraid I'm not very good at explaining things using just text but I'll have a quick go...The loop gain in a typical PLL will be very high near dc and it tails off with increasing frequency and eventually falls below zero at some frequency. If you then increase the CP current you increase the gain of the loop over all this range. This means an increase in loop gain at frequencies above and below the special frequency where there is unity gain around the loop. So if you increase the gain 'here' you actually create a new place where gain around the loop is unity. This will now obviously be at a higher frequency so the loop now has more bandwidth. SimpleI'm making a very significant increase in CP current from less than 0.5mA to over 5mA so it's no surprise that the loop BW has shot up a lot in my demo circuit. However, the stability of the loop can be compromised when doing this and a 'visual clue' to the degraded phase margin is when you see peaks in the noise on an analyser.I used an old Analog Devices eval PCB for my demo. It's an ADF4351 board although the loop filter parts have been swapped many times over the years so it isn't a standard board anymore. However, I think the latest values are only slightly different from the default values on the eval board datasheet.

author: G0HZU
author_rank: Super Contributor
timestamp: June 02, 2014, 01:01:30 am
content: Note: The reason I tend to pop up like a bad stain on spectrum analyser threads is because I used to design the RF downconverter stages for wideband ESM receivers used by gov/mil in the 1990s.These were effectively the same as our modern spectrum analysers like the Rigol 815 and 1030 in that the (tunable across LF to xGHz) downconverter fed to a digital IF using the (then) state of the art ADCs and DSP. Back then the ADC/DSP was the size of a huge rack system and cost an absolute fortune!It was effectively a race to see how quickly the whole RF spectrum from LF through to many GHz could be captured in DSP for whatever use the customer wanted. The performance had to be very good in terms of linearity, IF capture bandwidth, low spurious and conventional spectrum analysers were too big and heavy and slow and 'narrow' to be used instead of these specialist and very expensive receivers.I was lucky to have access to the very best spectrum analysers on the planet back in those days as design/eval tools and I had to study and learn their weaknesses. I also had to design the synthesisers used in the receiver as well as designing the signal path and so I was quite savvy about all this stuff back then. However, I don't design this stuff these days as our product base shifted a lot post 911. The last decent receiver/analyser I designed was way back in 2001

author: Sailor
author_rank: Regular Contributor
timestamp: June 02, 2014, 02:06:37 am
content: QuoteAh, ok. But also where invariably the phase margin will be less, hence peakier and noisier?Another point, to further demonstrate my lack of knowledge in these areas:Somewhere (earlier in this thread, I think), I thought there was the suggestion/implication that a lower close-in noise level was being achieved (at the expense of the humps being discussed) by increasing the loop bandwidth. Or, simplistically, that's the way I read it at the time. I always had the idea that lower-BW --> lower noise but slow locking, larger-BW ---> faster locking but more noise. Did I understand wrongly, or is there a way of suppressing close-in noise but still getting a faster lock?It sounds like you had an interesting career!

author: videobruce
author_rank: Frequent Contributor
timestamp: June 02, 2014, 10:22:40 am
content: QuoteI wish more would "pop up" here as you have.I have ruled out the FSH3 from my original list, but have not ruled out it's replacement the FSH4other than the street price which probably is out of my range. I did look into the Hameg, but kinda ruled that out as I have in the past due to the lack of interest in the US with the what appears to be the very limited availability.Add to that, it's AC only, The preamp is only 10db (most others are 17-20db), the preamp shuts off automatically above -10dBm & there appears not to have a marker table.I did notice on the front of the scope, the R&S name with the Hameg name below it.I also looked at the R&S FSL & the FSC, but other than the spec sheets, there seems to be very little elsewhere on either, just like the Hameg which gives me pause.One worst thing about shopping for higher end test equipment like this is trying to get a actual bottom line price. "List" prices aren't even available unless you hunt and/or call for them. Prices for motor vehicles costing as much as many of these higher end machines are commonly available, why does it have to be different here?

author: videobruce
author_rank: Frequent Contributor
timestamp: June 02, 2014, 10:02:24 pm
content: I have updated my 1st post to include the RSH4 (that replaces the '3' version) and the Rigol DSA-1030A.

author: Mr Simpleton
author_rank: Unknown
timestamp: June 03, 2014, 10:10:05 am
content: Quote from: Sailor on June 02, 2014, 02:06:37 amNevermind the pd current[simplistic mode]If you look at your VCO phase noise unlocked, this is what you will get outside of you loop filter cut off frequencyInside the loop filter cut off the noise will mainly be due to the referency x 20logN where N is the multiplication of the reference to get desired VCO frequency. With a single loop, and a large N you will get lots of noise close to carrier! You may realize the optimal phase noise behavour is a trade off between switching time, reference spur supression and noise.With the loop closed, the VCO cannot be "corrected" outside the loop bandwith, with a noisy VCO you may get lower noise inside the loop BW (you might even see a hump), but if the VCO is really low noise by it self, you may end up with higher noise with-in the loop BW due to multiplication of the reference[/simplistic mode]

author: videobruce
author_rank: Frequent Contributor
timestamp: June 03, 2014, 10:18:18 am
content: If we can get away from this discussion of phase noise,how about DANL??I've seen the video regarding that which was interesting, but I haven't seen the equivalent for DANL and how that affects various measurements.

author: KJDS
author_rank: Super Contributor
timestamp: June 03, 2014, 11:12:38 am
content: Quote from: videobruce on June 03, 2014, 10:18:18 amThe DANL is the fuzzy line at the bottom of the screen. The wanted signals can only be seen when they are large enough to be above the line. The closer they are to the line then the more error the noise will give to their magnitude. The DANL is usually specified in a 1Hz bandwidth. If you are measuring in a 10Hz bandwidth then the noise is 10 x larger so the fuzzy line will be 10dB higher. If a 100Hz bandwidth then 20dB higher and so on.Where a spectrum analyzer has a pre-amp then the DANL is usually specified with the pre-amp in. Without it then it will be higher and for each 10dB of attenuation switched in then the DANL will be 10dB higher again.

author: Sailor
author_rank: Regular Contributor
timestamp: June 03, 2014, 11:46:18 am
content: @Mr Simpleton: OK, thanks for that. I'll have to go away and mull that over...@videobruce: Sorry mate, I wasn't trying to hijack your thread. But when I see someone who knows 'way more than me about a subject, I like to try and learn something from them.

author: Mr Simpleton
author_rank: Unknown
timestamp: June 03, 2014, 01:56:15 pm
content: Sorry about obfuscating your thread m8Oh well, found a R&S ZVL spectrum (and network) analyzer. Smallish and quite portable but only 220 V. And using XP, took ages to bootBut what I had to try was the internal preamp... this one was manually controlled and did not switch off when adjusting reference level nor, input attenuator. The ref level maxed at 0 dBm using pre-amp on and 20 dBm with it off.Fast sweep, and not too bad UI, but nothing I would enjoy using, especially with XP running, big step up from the FSH3.Guess FSL is a close derrivate, optimized for spectrum measurement. Formfactor and layout pretty much identical.

author: free_electron
author_rank: Super Contributor
timestamp: June 03, 2014, 02:48:11 pm
content: The fsh3 is a problem child... When the battery deep discharges it takes out the i ternal charging regulator. It fries the power mosfet. That mosfet is a special 6 pin package and discontinued... The pin order is non-standard...I have already repaired two of those... A third one was unfixable as it burnt too much of the pcb.Second , the display... Bleeeeh 320x240 pixels...

author: videobruce
author_rank: Frequent Contributor
timestamp: June 03, 2014, 08:10:28 pm
content: QuoteNever thought you were, just didn't want to go too far off course on just one aspect of the equation.QuoteHow/why can that happen??Yes. that display is for sure the deal killer. One would think this was 1994, not 2014. I'd like to see a user review of the new 4.

author: G0HZU
author_rank: Super Contributor
timestamp: June 03, 2014, 10:59:52 pm
content: I'll post up some design tradeoffs/equations for DANL vs linearity later but I can't leave the phase noise cleanup debate ending on doubtQuoteYou absolutely DO get better phase noise cleanup of the very close in VCO noise (way inside the loop BW) if you increase the loop bandwidth. I can give you a classic/extreme example... (which hopefully ends the debate once and for all)My old HP analyser that dates back to the late 1970s has an LO that runs up at 2 to 3.5GHz but the measured close in phase noise down towards the 2GHz end is approx. -112dBc/Hz at a 500Hz offset. Yes, that's -112dBc/Hz at a few hundred Hz offset from a 2.1GHz LO carrier frequency. This is achieved because the loop bandwidth is very wide. eg it's set at about 100kHz. I think it actually achieves -112dBc/Hz at 300Hz offset but I can't be bothered to go and check this tonight.If the loop BW were reduced to 1kHz then there is no way the loop can clean up the (noisy) free running VCO noise to get as low as -112dBc/Hz at about a 500Hz offset.The penalty for this cleanup is that this analyser has relatively high phase noise way out at 100kHz offset. i.e. the phase noise at 100kHz offset is only a few dB better than the phase noise at 500Hz offset.

author: Sailor
author_rank: Regular Contributor
timestamp: June 04, 2014, 11:31:50 am
content: GOHZU, thanks for all your input on this.QuoteI'm not sure that it was a debate, at least certainly not on my part - I don't know enough about the subject to debate it. My interest is in trying to understand the mechanism by which it happens. My (one and only) textbook on PLLs certainly doesn't discuss it - hell, it barely has a couple of small sections on general noise considerations in the loop. I guess I'd better broaden my reading...

author: Mr Simpleton
author_rank: Unknown
timestamp: June 04, 2014, 01:59:21 pm
content: Quote from: Sailor on June 04, 2014, 11:31:50 amThere is more than one way to skin a cat...Still frequency generation, PLL, DDS and such are fun things, and when we noise-nuts get a chance we tend to jump right in head first.... Hate to admit I ended up playing with ADIsimpPLL simulation program past midnight just to see how G0HZU got his "hump".... Guess most of us do use the spectrum analyzer to look at how noise affect our signals hence we do end up in these topics, with good intentions I might add!Back on track, choosing a protable SA, having an absolut demand for built-in battery operation, narrow things down to a few, and consensus sees to be; stay away from the FSH3. Given this track record I would be a bit hesitant to spend dollars on R&S, so why not contact Agilent for a demo??

author: videobruce
author_rank: Frequent Contributor
timestamp: June 04, 2014, 09:19:36 pm
content: The FSH3 has been ruled out some time ago thanks to all the input here. I'd like to have a side by side of the 2712E & the 9430B.

author: videobruce
author_rank: Frequent Contributor
timestamp: June 06, 2014, 04:27:13 pm
content: Can someone post some screen captures from the 9340B?Does that and the 2711/12E have the ability to invert colors when saving a screen capture so it can be printed out w/o using a ton of black ink??

author: videobruce
author_rank: Frequent Contributor
timestamp: June 07, 2014, 12:54:22 pm
content: The Electrician;QuoteI just had the chance to audition a Anritsu MT8212E (I believe). Surely not what I was looking for, but it gave me a basic feel. Among other things, one thing I was looking for was the lowest sweep speed it could do. Not having a manual for this (the rep was suppose to have a 2712), we (both of us) were perplexed with the readout of sweep speeds. I had the unit in manual RBW, VBW & what I thought was a manual sweep setting, but it still had a mind of it's own. It let me enter slower or faster speed speeds, but it would then display what it wanted to. usually some odd number; 83, 167ms etc.On top of that, when trying to enter in another number, the display went into some other setting, what appeared to be a 1 sec sweep even those the readout was around 100ms.I'll report back on mine and his findings as he did contact Anritsu for this and other questions.One thing I surely don't like is their manuals, they are terrible. They donotshow a complete Menu tree. Only for the "File" and "System" menu entries. Nothing for all the other 'important' operational entries. You know, the ones that are used all the time.The fastest speed it did show was 50ms depending on settings.

author: ericha
author_rank: Newbie
timestamp: June 08, 2014, 09:14:58 pm
content: Quote from: videobruce on June 07, 2014, 12:54:22 pm

author: ericha
author_rank: Newbie
timestamp: June 08, 2014, 09:21:08 pm
content: Quote from: videobruce on June 07, 2014, 12:54:22 pm

author: ericha
author_rank: Newbie
timestamp: June 09, 2014, 12:26:31 am
content: Quote from: videobruce on June 07, 2014, 12:54:22 pmThis is a fairly complicated subject, but I think people reading this blog would be interested.First, there are 2 different major modes that a Spectrum Analyzer has--zero span and non-zero span. Let me talk about zero span first, as that's the simpler case.In zero span, the x-axis is longer frequency, but time. The LO in the instrument is parked at one frequency, and what you get is like an oscilloscope, except that you can tune it to different frequencies. You see the amplitude of the signal versus time. In zero span, the sweep time of the Anritsu handheld analyzers is very accurate, and can be as fast as 10 microseconds across the screen.Now for the non-zero span case.Before we get into what's going on with the instrument, let me point out that for most uses, you don't need to adjust the sweep time when the span isn't zero. If the instrument sweep time is in it's Auto setting, the instrument just sweeps as fast as it can (for the selected "Sweep Mode", which I won't get into here). There are some relatively uncommon cases where you do want to adjust the sweep time, however.The first is where you want to look at pulsed signals with a "pulse spectrum"--where the RBW is wider than 1/PRF. In a traditional analyzer, the pulses on the screen show the PRI (Pulse Repetition Internal or 1/PRF) of the pulsed signal. The Anritsu handheld analyzers aren't very good at this particular setup--due to the sweep time being fully synthesized (and sometimes done by FFT, but we won't get into that either here). There's more about "fully synthesized" below.Fortunately, you can easily see the pulse timing by using zero span, and can see the spectrum by using narrower RBW (at the expense of "pulse desensitization").The second time you want to adjust the sweep time in non-zero span is where you want more averaging of the signal than the VBW control can give. The VBW is limited to 1 Hz at the bottom end, but when you are using RMS/Avg detection, you can get more averaging than this by extending the sweep time.So while the analyzer can seem to have a "mind of its own" for sweep time sometimes, fortunately this usually isn't much of a problem for most measurements. One can wonder, however, why the instrument works that way. Let's talk some more about that.In a traditional (analog) Spectrum Analyzer, there is an analog ramp generator that tunes the LO to different frequencies across the span. As you might imagine, this isn't very accurate. Over the years a number of clever things have been done to improve on this, including "lock and roll", first done I believe in the HP 8566/68 analyzers. In this case, the start (or possibly other) frequency is synthesized, and this is used as the beginning voltage/current for the sweep. As I remember in the 8566/68, narrower spans had the frequency stabilized by using a discriminator, but I don't remember the details.The Anritsu handheld Spectrum Analyzers take a different approach. Every frequency point is fully synthesized. This makes the frequency accuracy exceptionally good. But it makes the sweep time very complicated. This is because the time it takes for a synthesizer to lock up & settle is not precisely known beforehand--it depends on the frequency and phase of the VCOs in the system when the process starts, something that is somewhat random. On top of that, the fastest sweep time is a function of many more things than you might imagine--not only the RBW & VBW as in traditional analyzers, but also the detector settings and the frequencies being used. One of the reasons for this is the complexity of the L.O. needed to be able to tune over a wide frequency range (GHz) with very fine frequency resolution (effectively Hz), as well as really good close-in phase noise. The 1st L.O. in these instruments is much more complex than the simple single-loop structures that have been discussed elsewhere in this thread. Another reason for the minimum sweep time being a complex function is something called "spur avoidance". There are certain frequencies where spurs would be bad for the way the LOs normally work; at those frequencies the 1st & 2nd LOs can be tuned to slightly different frequencies than would be normally used, making the tuned signal appear at the right place in the IF, but making the spurs go outside of the IF bandwidth. This is pretty clever, as it allows wide IF bandwidths (which tend to cause more spurs), but it takes time.Another complicating factor is that because the RBW and VBW are done digitally, there is somewhat limited control of exactly how fast the sweep can be. The instrument can dwell at a particular point to get 2 or 3 points out of the RBW filter, but you can't get 2.5 points. So some sweep times just aren't possible given the way the instrument works.To further complicate this, the method of dealing with this variability of the sweep time in the Anritsu handheld analyzers has changed somewhat over time. To have a precise discussion, we need to know what version of firmware for the instrument we are discussing. The latest firmware for the MT8212E is V1.53, introduced just last month. In this version (and several earlier ones), when you enter a sweep time, the instrument uses a model of how long the sweep will take for a particular instrument setup. This is characterized for thousands of setting combinations, and the closest one is picked. Then it calculates the closest multiple of that time to the user-selected sweep time, and extends the dwell time at each frequency point by that factor. That estimated value is put on the instrument display, preceded by a "~". The instrument then actually measures it's own sweep time, and displays the actual value.Now we have to talk about the definition of "sweep time". On many analyzers, if you have it set up to tune across a wide frequency range, if you use a stopwatch to time the sweep, you will find that the actual sweep time doesn't match what's displayed on the instrument. How can this be? There are points during the sweep when the instrument isn't sweeping, but doing something else; the most common of these is switching bands, at least for microwave analyzers. So for these analyzers, the "sweep time" isn't the total time, but rather the time the instrument is actually sweeping. In the Anritsu handheld Spectrum Analyzers, however, the measured sweep time is the time for the total sweep, including all of that non-sweeping time.Another point worth commenting on is the need for sweep times faster than about 100 ms when the span isn't zero. Two points come to mind about this. The first is that for many setups, you won't be able to get anything near this time. This is because larger spans and smaller bandwidths take longer--that's just physics. There are some tricks that can help (like using an FFT), but they only go so far. When you have 1 Hz RBW, it's going to take at least 1 second, no matter what you do. If this span is large with a narrow RBW (like 1 Hz), it's going to take many seconds to get a complete trace.The second is that the human eye can only see so much--update rates much faster than 10/second are nice, but it's hard to see much of what's going on. There are cases where faster sweeps can be helpful, such as when trying to capture a brief pulse--but there may be other ways to do that--but that's probably a topic for another thread.I hope that helps clarify what's going on in the Anritsu handheld spectrum analyzers, as far as the Sweep Time is concerned.

author: videobruce
author_rank: Frequent Contributor
timestamp: June 09, 2014, 10:30:07 am
content: ericha;Thanks fore the links, but the 1st one is dead. Also, watch your quotes, the close quote got misplaced, you quoted your whole post.Their "library" tabs have too long of a list, hard to find anything quickly. I'll look closer.

author: ericha
author_rank: Newbie
timestamp: June 09, 2014, 01:40:06 pm
content: Quote from: videobruce on June 09, 2014, 10:30:07 amSorry about the link--there is an extra period at the end that shouldn't be there. Here is the correct link:http://www.anritsu.com/en-US/Downloads/Manuals/Measurement-Guide/DWL8487.aspxThanks for the hints about quotes:).

author: Unknown
author_rank: Unknown
timestamp: April 16, 2015, 07:34:54 pm
content: Hello all,Rohde Schwarz FSH-3 and 6 power on problems?Replace NDC651N N channel fet or replace the NDC651N with the SI3454ADV-T1-E3 (pin 6 bent up and over to pin 5)Best regards,Marcel