USB network analyzers -- as bad as USB oscilloscopes, or not? - Page 1
Forum section: electronics / testgear

author: rs20
author_rank: Super Contributor
timestamp: August 03, 2015, 04:46:48 am
content: I agree entirely with the statement that USB-based oscilloscopes are a fairly bad choice compared to, say, a DS1054z. Performance, waveform/sec, OS compatibility and responsiveness issues aside, the knobs and buttons on a "real" oscilloscope are so lovely and tactile that you can find and use them without even looking. I see that this is a good thing, compared to messing around with a mouse.However, I saw a recent (excellent) video by Shariah discussing the Signal Hound BB60C USB signal analyser, and it got me thinking. I was considering the Rigol DSA815-TG 1.5 GHz spectrum analyzer, but the specs of these PC-connected units appear (to my untrained eye) to be vastly superior. Am I missing something; does the DSA815-TG have any advantages to justify the equal cost for 1.5 GHz (compared to the 4.4 GHz Signal Hound USB-SA44B + USB-TG44A)?DSA815-TGSA44B+TG44APrice $1495 $1475Frequencies 9 kHz to 1.5 GHz1 Hz to 4.4 GHzDynamic range ?? -151 dBm to +10 dBmAmplitude error "<1.5 dB" "+/- 1.5dB"DANL -135dBm ("typical")-135dBm at worst (from 10kHz to 3.3 GHz)Phase noise -80 dBc/Hz @10 kHz offset ??Now I know that "which X is better" type question are often dumb and often best answered with "depends on your usecase" -- so to be more clear, can someone please contrive a usecase for which the DSA815-TG would be better?*And what about the PC vs standalone device question? With oscilloscopes, the interactivity and speed of custom-layed out physical knobs is considered by many to be critical for usability. Is the spectrum analyzer workflow typically so different that this isn't true? (Seems plausible to me that there's less "hunting for a signal" or deep zooming/scrolling with an SA compared to an oscilloscope, and that with an SA it's more common to set up a fairly intricate configuration, and then you hit "go" and watch the result roll in -- more computer-suited, less interactivity-suited).* For the record, my usecase is "random/general use" -- e.g., testing cables, exploring the RF in my neighbourhood, analysing control loops, messing about with time-domain reflectometry, ultrasonic transducers, etc, etc.... just random hobbyist stuff.

author: tggzzz
author_rank: Super Contributor
timestamp: August 03, 2015, 08:44:59 am
content: Quote from: rs20 on August 03, 2015, 04:46:48 amIf that's "all" you want to do, you may like to consider using an RTL SDR dongle plus noise source. There are significant limitations, of course, especially dynamic range scanning time, 25MHz-1.5GHz, but they only cost £40 or so! Think of it as a reason to use thought and imagination

author: pascal_sweden
author_rank: Super Contributor
timestamp: August 03, 2015, 06:04:22 pm
content: The general issue with using a computer is that the operating system could start to exhibit stability issues, when you install too many applications on it.This can be of course solved, by reserving a dedicated computer, which you only use for connecting the USB signal analyzer, and on which you don't install any extra software.But still you will always have to boot your computer, and boot times can be longer with a computer compared to with embedded test equipment.Last but not least, a real Spectrum Analyzer is just more impressive and show off on your test bench. The Rigol DSA815-TG is very affordable and a nice show off equipment. Much better than an old laptop and small USB boxMost electronics hobbyists here use computers for reading email, browsing the internet, and playing some games in a while. When it comes up to test equipment, they prefer the real deal.That includes also analog test gear from several centuries, covering the 70's, 80's, 90's and beyond

author: pickle9000
author_rank: Super Contributor
timestamp: August 03, 2015, 06:09:08 pm
content: Quote from: tggzzz on August 03, 2015, 08:44:59 amAnd just fun to play with!

author: rs20
author_rank: Super Contributor
timestamp: August 03, 2015, 11:56:56 pm
content: Quote from: tggzzz on August 03, 2015, 08:44:59 amA very interesting concept, and I thank you for suggesting it. And I already have an RTL SDR in fact! But I don't much enjoy the prospect of writing the code to convert it for all the reasons above, especially when the chip in question is not designed for anything other than video and the manufacturer does not support this usecase at all. It also doesn't cover the control loop, ultrasonic and TDR cases particularly convincingly either?I'm mostly interested to hear from people that have used both USB and standalone network analyzers, and have opinions comparing the two.

author: G0HZU
author_rank: Super Contributor
timestamp: August 04, 2015, 12:43:34 am
content: Sadly, few people have the knowledge and experience to do a decent technical review of the RF converter section of a spectrum analyser. I've not seen anybody on the various blogs who really knows what to look for. From a technical point of view the reviews are pretty lame and don't even do any basic/classic tests of a spectrum analyser.But then I think the rules for what makes a good spectrum analyser have changed in the last 5-10 years or so because there appears to be a new type of user. i.e. someone who doesn't have a typical RF background but who wants access to modern analysis technology (eg RF>digital IF and maybe also SDR) and is prepared to sacrifice RF performance and design integrity in order to get these modern features at an affordable price.So you get disruptive products like the DSA 815 and the SH44 and the Tek RSA306 appearing on the market and these are tailored towards this type of user rather than someone like me who wants/expects some classic design integrity from a spectrum analyser. But this integrity normally comes at huge expense in terms of size, power, weight and cost.I'd like to review both of the 815 and the SH44 but I doubt the manufacturers would want someone like me to do this as I would do a classic analysis of the RF converter design with a view to predicting (and measuring) the spurious performance and also do the various classic tests of dynamic range.I did get a few hours with a Tek RSA306 demo unit and after some basic reverse engineering I managed to model/predict how awful the spurious performance was in some places. It's claimed to achieve about 50dB spurious free range but I was quickly able to model it and measure it and prove it was only about 9dB in places due to some pretty awful frequency planning in the RF converter. I only had one evening or so with it before it had to be returned.I would expect to find similar holes in the performance of the Rigol and SH analysers but I doubt I will ever see one of these.

author: G0HZU
author_rank: Super Contributor
timestamp: August 04, 2015, 01:03:38 am
content: QuoteI've not used the USB VNAs but some of them do look to be quite useful/accurate up into the VHF region. I'm a classic user of a modern lab VNA with access to various modern xxGHz VNAs at work and my typical use of a VNA is to take 2 port (or n port) models of components/circuits for subsequent modelling on an RF simulator on a PC. i.e. use the VNA to create/export .n2p s parameter files for various components etc.I've not seen much evidence of people using the USB VNAs like this but I'm pretty sure it could be done successfully if the bundled SW allowed it. I'd be interested to see just how successful this could be with a little USB VNA because I'd consider buying one for LF/HF use even though I have a reasonably good HP VNA here at home.My VNA is fairly old (1990s 3GHz model) and it would be nice to have something smaller and more efficient when it comes to taking accurate 1 or 2 port models of various components up into the VHF region.

author: w2aew
author_rank: Super Contributor
timestamp: August 04, 2015, 01:48:00 am
content: Quote from: G0HZU on August 04, 2015, 12:43:34 amFor what it's worth, I tested an RSA306 that was updated with the latest firmware, which includes updated frequency plan and vector calibration, and the SFDR under those test conditions you showed was dramatically improved.

author: tggzzz
author_rank: Super Contributor
timestamp: August 04, 2015, 07:12:48 am
content: Quote from: rs20 on August 03, 2015, 11:56:56 pmIt depends on what you mean by "convincingly". For the TDR example I can already clearly measure the lengths of 19 cm and 29cm open/short circuit stubs located 3.1m along cable. In theory 1.5GHz => "distance quantisation" of 3.3cm. I'm still improving my technique for measuring the impedance/magnitude of discontinuities.As and when I'm satisfied with my techniques, I'll publish my code.People like G0HZU will, quite correctly, point out all the imperfections and limitations of the tools - but I merely regard that as a challenge(After all, how do you test the fastest scope or highest frequency SA in the world?)

author: Howardlong
author_rank: Super Contributor
timestamp: August 04, 2015, 07:37:06 am
content: In some ways it depends how often you use it and the convenience that a purpose made device offers. Personally, while I can see the initial excitement, I'd find it immensely boring using an SA to search out random signals across a great swathe of spectrum. SAs also tend to be significantly less sensitive than SDRs, so I'd suggest that using an SA on its own to search out elusive signals from the ether isn't necessarily the best tool, at least not on its own. Equally, SDRs tend to have limited spans compared to SAs. But as you increase the span on your SA, typically the sensitivity decreases, or the sweep takes a lot longer.So what do I use? For the occasional field work for testing things like satellite uplinks I use a TTi PSA hand held SA and an Anritsu Sitemaster for a VNA. However most of my work is at my home office/lab, so I have a number of SAs of varying ages and frequency ranges. The usual go-to SA is the DSA815-TG, but I also have SAs to 3GHz and 26GHz but they are of the boat anchor variety, and although reasonably trustworthy, they don't have all of the modern features of the DSA815. For probing receiver signal paths, I often use an SDR with a home brew probe, and signal generator: you don't have to look up all the time, because you can hear the S/N by ear and identify where gain sections aren't working. While an SDR is little use for absolute measurement, they are reasonably handy for relative measurements, especially with weaker signals.For VNA in the lab, I use my trusty old 8753A, it still works well and since replacing the CRT with a Newscope colour LCD it looks like a relatively modern instrument. I don't use it every day. Like the SAs I have, their use tends to be in sporadic bursts, unlike the oscilloscope which is on most days.

author: pascal_sweden
author_rank: Super Contributor
timestamp: August 04, 2015, 07:48:26 am
content: Quote from: G0HZU on August 04, 2015, 12:43:34 amSo you are saying that the R&D department at Tektronix, with many skilled engineers, having years of knowledge and experience, have missed things that one person can spot in a few hours?How is this even possible? Hard to believe for me. Imagine they read your comment here.I am sure that the R&D department is very proud on their art, and would never tolerate such basic sacrifices. If they have made design decisions to reduce the cost, they probably have thought about them in a clever way, so that these design decisions don't affect performance and that the product is still within spec and margins allowed in the RF industry.Or to put it in another way: if you are that smart, and are the only person who knows how to do it right, how come you don't work for Tektronix? =)

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: August 04, 2015, 09:17:07 am
content: Quote from: pascal_sweden on August 04, 2015, 07:48:26 amBased on the information available it wasn't really that hard to see where the flaws of the Tektronix device will be and to predict how it will perform. G0HZU also wasn't the only one who came up with that assessment.QuoteThat paragraph is a load of bollocks. "Art"? "Spec and margins allowed in the RF industry" (what "RF industry" exactly, as there isn't just a single one)? Seriously?The point is that the Tek device was made for a price point, which meant they had to cut some corners. The corners Tek cut are different than the corners Signal Hound has cut to get the price point for their USB SAs right. If you believe that cutting corners won't affect performance then you're deluded. There are laws of physics which can't be ignored, even not by Tek engineers.QuoteOne reason could be that people with certain skills rarely have problems finding good jobs, and that means not having to work for a company that has been in decline in its core markets for over a decade and has seen more lay-offs than any other big T&M brand. Tek has been the to-go brand for scopes in the analog scopes days, but these days they are merely following while others (predominantly LeCroy) are the ones pushing scope technology forward. In addition, Tek was never renowned for their spectrum analyzers, which even in the good old days were mediocre at best (the old saying was "the scope from Tek and everything else from HP"). The companies that really understand spectrum analyzers are Keysight and R&S.I often find myself disagreeing with G0HZU, but in this case I have to defend him, as I find your attack highly unfair, even more so when it comes from the corner of "no clue".

author: pascal_sweden
author_rank: Super Contributor
timestamp: August 04, 2015, 09:28:11 am
content: I was just wondering, as the spots that Tektronix seemed to have missed, seem to be fundamental issues, affecting basic functionality. Or did I misinterpret?So what are the weaknesses in the Rigol DSA815-TG?In which areas doesn't it perform well in the 1,5 Ghz operating range?I thought it is limited up to 1,5 GHz compared to the A-brands that go above 7,5 GHz, but that it performs well within its 1,5 GHz operating range.

author: KJDS
author_rank: Super Contributor
timestamp: August 04, 2015, 09:50:14 am
content: Quote from: pascal_sweden on August 04, 2015, 09:28:11 amIt was indeed a basic miss from Tek. It didn't take much to make a significant improvement, only a few tweaks of the software, which tells you a lot about how far Tek have fallen from the greatness of their analog scopes.

author: G0HZU
author_rank: Super Contributor
timestamp: August 04, 2015, 04:27:14 pm
content: Quote from: pascal_sweden on August 04, 2015, 07:48:26 amYes, they made various basic errors in the design of the frequency plan of the RF converter in the RSA306. I would suggest that the person who chose the plan had limited design experience and the thing that amazes me is that this thing got through a basic design review of the frequency plan let alone a critical design review involving many engineers and other types of employee.QuoteTo give you some background, I was designing high performance and very expensive RF downconverters for wideband SDR type radios for gov/military use as far back as 1990. So I've had plenty of time to gain experience in what is good/bad and how to evaluate a frequency plan for spurious performance etc. I doubt Tektronix were doing anything like this back then. The RSA306 that I was given to try out had a frequency plan that was laughably bad in places. We are talking unforgivable errors (as in errors that break even the most basic rules of frequency planning) that only an inexperienced engineer could make. Therefore, I can't believe they have any proper design review process in place for products like this.QuoteAgreed. I think it's the fact that this basic error wasn't spotted that is the most amazing thing. I found it by reverse engineering their frequency plan using another spectrum analyser but I was laughing even before I entered the frequency plan data into a spurious prediction program because it was so obviously flawed.

author: Hugoneus
author_rank: Frequent Contributor
timestamp: August 04, 2015, 04:46:58 pm
content: As someone who regularly uses instruments ranging from $50 to $500k on a daily basis, I can tell you that I have to tailor my reviews to the instrument's intended use and audience. This is inevitable. For example I put the Keysight S-Scope through much tougher tests than I did the USB-based spectrum analyzers (although I specifically showed and complained about the spurious response of the RSA). I specifically design tests to show the instrument's capabilities and limitations and that already takes more than one hour of video and more ten times longer to prepare. It is not matter of expertise necessarily, it is a matter of practicality and time.

author: G0HZU
author_rank: Super Contributor
timestamp: August 04, 2015, 04:58:30 pm
content: The other thing that surprised me was they Tek's frequency plan was so basic that they didn't include even the simplest of spurious shift/avoidance algorithms. These are things you can get for free in firmware as long as the HW can support this (and I think it can).I would hope/expect they have improved this as well. My first thought was that someone had given me an early beta version of firmware but apparently it was a general release version.I doubt I'll get to see a revised RSA306 because I don't think the company is going to buy one even though I thought it was still a useful tool for parts of the frequency range that were reasonably spurious free. But hopefully someone else will review one of the updated versions.

author: G0HZU
author_rank: Super Contributor
timestamp: August 04, 2015, 05:35:03 pm
content: QuoteTo predict and find the spurs that I found required a degree of reverse engineering which I didn't see others doing. I was able to predict and find places where you put one signal in and it displayed it twice with the ghost version only 9dB lower.This applied to all signal levels so if you put in a fairly large signal at -10dBm it would show the -10dBm signal and another copy of it (not far away) at just 9dB lower! This is very different to the internal low level 'birdie' spurious signals seen in other reviews. To find these special places where this happens at its worst you ideally have to know the frequency plan and know how to model the generation of the spurious signal so you know how to set the centre frequency and span that opens the door for this spurious mechanism to rear itself.Of course, you could also find them by pure chance but I didn't see any review with this particularly nasty type of spurious mechanism presentI did also find other issues (bugs?) with the way it builds up a wide span on the display but these weren't as significant. But still surprising to see stuff like this from a big name like Tek.If I had been allowed to keep it for a week I would have probably found more issues but I only had a few hours to reverse engineer the plan and then evaluate the RF downconverter section with a few classic tests.To give an example see the image below. There is only supposed to be one test signal on the screen. But I was able to predict a particular centre frequency and span that displayed the same test signal several times at various levels. eg it displays a copy at -9dBc and another at -15dBc and another copy lower down still. There's only supposed to be one tone displayed!So the spurious signals in the image below are all ghost copies of the main test signal and they suddenly appear along with the main test tone as it is injected into the analyser. This isn't very impressive for something that is marketed as a spectrum analyser

author: hendorog
author_rank: Super Contributor
timestamp: August 04, 2015, 09:53:00 pm
content: Isn't it (more) interesting that the performance of the Tek was able to be radically changed with a firmware upgrade?Rapid development (with known issues), and reacting quickly to resolve issues is in line with the software world these days.Thats one advantage of a USB instrument - more of the instrument is software, and so can be upgraded.Signalhound did this recently with a rewrite of their UI which was a massive improvement on the old UI.

author: G0HZU
author_rank: Super Contributor
timestamp: August 04, 2015, 10:29:54 pm
content: To clarify things a bit the issues I found were to do with how they were managing/programming the hardware inside the box wrt the frequency planning for each tuned frequency (rather than this being something fixed in the PC/DSP/SDR part of the system)i.e. these were fundamental mistakes in the management of the hardware in the RF converter and they also failed to deploy even the most simple of spur avoidance algorithms anywhere within this hardware.

author: MagicSmoker
author_rank: Super Contributor
timestamp: August 04, 2015, 10:39:31 pm
content: I bought the Signal Hound SA44B a couple years ago just to do "pre-compliance" EMC testing (along with a homemade log-periodic antenna) and it performed reasonably well, especially given the price and ease of use. This is the type of test equipment that I might use once a year, so a more capable device was neither justified on price, nor on the inevitable steepness of the learning curve.I did not buy the tracking generator because I had no intention of doing immunity testing and a scalar network analyzer (ie - characterizing frequency response but not phase) isn't much use to me.My opinion - based on very limited usage - is that the Signal Hound is a capable instrument and a good value.

author: w2aew
author_rank: Super Contributor
timestamp: August 04, 2015, 10:52:49 pm
content: Quote from: G0HZU on August 04, 2015, 05:35:03 pmI would say that the current firmware made a substantial improvement:

author: G0HZU
author_rank: Super Contributor
timestamp: August 04, 2015, 11:14:26 pm
content: That does look cleaner, but I'd have to have one here to see if the new frequency plan is truly better across all tuned frequencies. The only way I could do this is to reverse engineer it again to map out the complete frequency plan for every frequency step in the whole range and then analyse it for issues.Or maybe Tek could release the revised plan in paper format for people to review. The first plan was so flawed and basic it will take more than one screenshot to convince me that the analyser is now 'fixed' in this respect

author: pascal_sweden
author_rank: Super Contributor
timestamp: August 05, 2015, 12:23:36 am
content: Quote from: G0HZU on August 04, 2015, 04:27:14 pmNice job about the reverse engineering. Hats of for smart people like you!

author: rs20
author_rank: Super Contributor
timestamp: August 05, 2015, 12:35:48 am
content: Thanks everyone for your input; there's a bunch of part numbers and model listed that I shall take a look at in the coming days! It's also interesting to note that no-one seemsparticularlyopinionated on the standalone-vs-USB thing. I also really appreciate the other discussion in this thread.Just briefly, does anyone know what the Signal Hound actually sends over the USB link? I/Q samples, frequency/magnitude pairs, or something else? I'm trying to get a sense of what proportion of the cleverness is in driver/UI software vs actually on the device.Quote from: tggzzz on August 04, 2015, 07:12:48 amCool! What software did you use to interface to the SDR? I.e., did you write your own code to talk to the USB directly, or did you use some software to take a frequency sweep or something for you? Did your code start with a list of frequency/magnitude pairs, or a pile of I/Q samples?Quote from: hendorog on August 04, 2015, 09:53:00 pmIs that pre-or-post Shahriar's review? Speaking of which:Quote from: Hugoneus on August 04, 2015, 04:46:58 pmYour efforts are very very much appreciated!

author: hendorog
author_rank: Super Contributor
timestamp: August 05, 2015, 12:59:37 am
content: QuoteThe BB60C that Shahriar reviewed always had the 2nd gen software. I was referring to the SA44/SA124 models which originally came out with a fairly agricultural UI. Now the two share the same software and the API's have been brought into sync as well.QuoteThe Signalhounds have three modes - zero span, swept and real-time.From the perspective of the API you can get IQ info when in zero span or swept mode, but only frequency/magnitude info in real-time mode. There was a discussion on their facebook page and it seems that IQ info isn't available for the realtime samples.So I suspect that is how it comes from the device as otherwise they would just add that to the API.

author: tggzzz
author_rank: Super Contributor
timestamp: August 05, 2015, 01:08:25 am
content: Quote from: rs20 on August 05, 2015, 12:35:48 amIt is based on Kyle Keen’s program rtlpowerhttp://kmkeen.com/rtl-power/outputs frequency/magnitude pairs. I wrapped that with four Python scripts to do the processing I wanted.Somepreliminaryresults are athttps://entertaininghacks.wordpress.com/2015/07/27/poor-mans-homebrew-tdr-with-4cm-resolution-part-1/Please note thepart 1implies this is a start, and that I intend to explore improvements in subsequent parts.Today I used the SDR to estimate the rise/falltime of a digital signal. Itappearsthat 3 parallel 74LVC1G14 gates driving a 50ohm line have a rise/falltime of around 600ps.

author: dr.diesel
author_rank: Super Contributor
timestamp: August 05, 2015, 01:09:42 am
content: Quote from: Hugoneus on August 04, 2015, 04:46:58 pmA preview of such a device would make a great video!

author: G0HZU
author_rank: Super Contributor
timestamp: August 05, 2015, 01:20:09 am
content: QuoteNote that the SH44 concept is based on a frequency plan that is highly unconventional. It's a long time since I looked at the block diagram but this analyser relies on a very unconventional image detect/reject system that allows it to use very low first IF frequencies. This means they can design and build something very small with very low cost if they can manage to make this system workable.I've not had one to play with but I'd expect the RF section to have some significant weaknesses and flaws. I suspect that this won't prevent it from being a very useful (and powerful) instrument but it doesn't possess the classic design integrity of a conventional analyser. However, I'd expect most users to be quite happy with it and they may well never use it in a way that exposes its unconventional design limitations.

author: hendorog
author_rank: Super Contributor
timestamp: August 05, 2015, 01:32:52 am
content: QuoteThe detection scheme you are talking about is their method for doing two sweeps switching IF frequencies each time. Then they can use the differences to work out whats a real signal and what's not.The downside is that hopping signals are hard to detect as the spur detection algorithm will hide them if they hop in between the two sweeps.AFAIK That only applies to the swept mode, not the realtime mode.

author: KE5FX
author_rank: Super Contributor
timestamp: August 05, 2015, 02:55:21 am
content: In Tek's defense, I'd also point out that the RSA306's requirement for 40 MHz of realtime analysis bandwidth rules out some of the usual spur-avoidance hacks. For instance, it's all well and good to plot the minimum response from N sweeps with N different IFs, as Signal Hound does, but that's not the least bit helpful if you need to demodulate the baseband signal or otherwise need to minimize dead time at (almost) all costs.Not having examined it in detail, I'd guess that the worst spurious responses from the RSA306 will arise from integer-boundary spurs from the MAX2870 LO synth chip they use. Assuming they can't vary the reference frequency dynamically, there is nothing they can do in real time to dodge those spurs in software. When I need SFDR, nothing beats the old-school HP iron... but hey, I also can't get a 40 MHz realtime data stream out of my 8566B, so it's horses for courses. The RSA306 and its competition from Signal Hound are really nifty gadgets.

author: hendorog
author_rank: Super Contributor
timestamp: August 05, 2015, 03:06:17 am
content: QuoteThere is a magic switch for that exact issue in the MAX2870 according to the datasheet, perhaps turning that on was part of the fix:If the device is in frac-N mode, it will remain in frac-N mode when fractional division value F = 0, which can result in unwanted spurs. To avoid this condition, the device can automatically switch to integer-N mode when F = 0 if the bit F01 = 1 (register 5, bit 24).

author: Rupunzell
author_rank: Frequent Contributor
timestamp: August 05, 2015, 03:25:05 am
content: Cannot agree with this practice of scaling testing and evaluation based on expected users and intended market. ALL instrumentation should be subjected to the same testing and evaluation rigor and standards even if these standardized test are extremely time consuming and proves the Instrument Under Test as poor and problem ridden or exceptional.This line of thinking and methodology would be similar to alter the international standard for one volt to accommodate the instruments intended market.It also tends to plays into potential user's belief of viewing (measurement) what they want to believe for a given instrument. While this serves to sell instrumentation, it can and will fool less astute users into believe their measurements are completely and absolutely accurate and honest under conditions that the user may not fully understand the possible sources of error and related problems. This specific item is most problematic for those with the least experience and greatest expectations.Bottom line, one methodology for testing ALL spectrum analyzers regardless of cost, brand, type or else.Anything less easily falls into deception and deceiving potential customers and their expectations.BerniceQuote from: Hugoneus on August 04, 2015, 04:46:58 pm

author: KE5FX
author_rank: Super Contributor
timestamp: August 05, 2015, 03:36:11 am
content: Quote from: hendorog on August 05, 2015, 03:06:17 amThe issue comes in when you're in fractional mode at a frequency close to an integer multiple but not quite coincident with it. You get a spur at the integer multiple of the PFD comparison frequency. The data sheet is (deliberately?) very vague about just how bad those spurs can be. They can be very bad indeed.Of course, if the wideband IF path is broader than strictly required to support the analysis bandwidth, that could give them a way out of that dilemma. They may not even need to use those chips in frac-N mode, for that matter.

author: hendorog
author_rank: Super Contributor
timestamp: August 05, 2015, 05:09:50 am
content: QuoteAh OK thanks I'll need to read up about it. The reason I'm so interested (sorry, I don't want to derail the thread) is that I've got a couple of MAX2870 eval boards here and I'd like to see the spurs. I haven't been able to make it happen yet, but I'm sure it will if I hit the correct scenario.Edit: Spurs found

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: August 05, 2015, 05:31:00 am
content: Quote from: G0HZU on August 04, 2015, 05:35:03 pmWhen the Tek came out reviews seemed to pop up all over the places, and I'm pretty sure I read about similar problems in another. Although I didn't pay that much attention as I wasn't particularly interested in this Tek device.QuoteYeah, that looks pretty bad. Makes it pretty useless as a general purpose SA.How was the software?

author: pascal_sweden
author_rank: Super Contributor
timestamp: August 05, 2015, 06:30:34 am
content: Did they sell a lot of that Tek device?So they did never release a fix under all those years, and the actual fix still has to come?How many years are we talking about, starting from the launch of the Tek device?

author: hendorog
author_rank: Super Contributor
timestamp: August 05, 2015, 07:56:33 am
content: QuoteQuoteYou probably saw it by now, but w2aew posted a pic on the previous page showing a improvement with the update.Shahriar's Signalhound BB60C review compared with the updated Tek at the time he compares the harmonics:https://youtu.be/3txkDU-qy9k?t=1202This is his review of the old one, at about the time he shows the harmonics:https://youtu.be/GDcuRTOCj_s?t=960

author: G0HZU
author_rank: Super Contributor
timestamp: August 05, 2015, 07:01:19 pm
content: QuoteUp until maybe 5 years ago I would completely agree with you and so would a lot of engineers. But I really do think that there has been a change away from the traditional (and expected) design integrity of a decent spectrum analyser. I think a significant chunk of today's users don't care much about spurious free dynamic range or many of the other benchmark tests associated with a spectrum analyser. i.e. they won't care (or even understand or even want to understand) the limitations of the RF converter in the instrument. They will simply want to buy it and use it and just accept what they see on the display unless there is an obvious anomaly.For many users the features that are offered by the back end DSP and the amount of analysis bandwidth are the key features they want. If they can get these features cheaper by buying an instrument without the classic designintegrity expected in the RF converter of of a traditional analyser they will choose that option because they probably don't fully understand what tradeoffs they are actually making. In many cases their decision will prove to be OK because they may well never use the instrument in a way that shows up the design compromises of the cheaper instrument.So I think it's a case of giving the customer what they want and being less open about the true limitations of the instrument. For example, the glossy datasheets for lower cost analysis instruments (from the major manufacturers) often concentrate on the back end analysis features but will deliberately be very vague about the specifications and capability of the RF converter section.So you generally won't see the classic performance data that you normally expect to see from a classic HP/Agilent lab analyser. Less info here is 'more'

author: hendorog
author_rank: Super Contributor
timestamp: August 05, 2015, 09:00:26 pm
content: QuoteLess price is more tooLess weight, less age, less noise, less shipping cost, less repairsQuoteIt's incorrect to assume people will all be tricked into buying a cheaper instrument. Many people - myself included - don't have the budget to afford the new prices commanded by the high end gear so look at ebay. Ebay is only useful for this if you happen to be close as long haul shipping these elderly boat anchors is expensive and risky.Google is an easy way to find out things the manufacturer doesn't tell you before you buy. I bet a heap of people on this site found it because they were looking for an honest review of something or other.Also I think there is a danger of lumping all of these USB devices into one bucket. In fact they are actually quite different.The OP was looking at the SA44, which is an alternative to the traditional SA, just much cheaper.The Tek and the BB60C are wideband and as you and w2aew mentioned, offer something that an old school SA can't do.Signalhound are pretty upfront about what their devices can and can't do, and the company has a background of repairing HP spectrum analysers FWIW.I have the SA124 and I think it's a fantastic tool when paired with the TG, and I haven't regretted buying it. I didn't look at the Rigol SA because it didn't offer the bandwidth. 12GHz vs 1.5Ghz was a bit of a no brainer for a bit more money. Since then Rigol have released higher bandwidth devices, but the prices are too high.

author: G0HZU
author_rank: Super Contributor
timestamp: August 05, 2015, 09:48:44 pm
content: QuoteI didn't really mean 'all' people and I'm not sure 'tricked' is the right word to use to describe what I mean. I think there is an explosion of a new type of (casual?) user today who doesn't have the usual background that would normally lead them towards buying a spectrum analyser. I can remember back to the 1980s when only a select few individuals owned a commercial spectrum analyser and back then, not many people would actually want one anyway.Yet today you can find people from all walks of life wanting to buy 'dongle' SDR type analysers or instruments like the Rigol 815 or the Signalhound.Many of these people will not know about (or be able to give figures for) the more advanced figures of merit for a spectrum analyser or how to test for them and I'd argue that they probably aren't that interested in this info either. If they were interested then the various online blog reviews of spectrum analysers would be awash with critical questions about what key performance data was missing from the analyser review. I'm talking about classic, basic tests of a spectrum analyser.I think the various manufacturers are aware of this and so a new breed of analyser is emerging that is geared towards this type of user. i.e. something cheap but flawed but the target user doesn't mind or care and probably doesn't want to fully understand the limitations of the instrument. They just want to play with the power of the back end processing and they aren't really that concerned about the design integrity of the RF converter ahead of it.

author: tooki
author_rank: Super Contributor
timestamp: August 05, 2015, 10:50:26 pm
content: Quote from: pascal_sweden on August 03, 2015, 06:04:22 pmOK, so I know this is basically off-topic, but that's just nonsense. If there are conflictingdrivers, this can cause stability problems (though it's rare on modern OSes where drivers run in user space), but the number ofapplicationsinstalled is completely irrelevant to system stability.

author: G0HZU
author_rank: Super Contributor
timestamp: August 05, 2015, 11:40:12 pm
content: QuoteSorry, I missed that question.I only had the RSA306 analyser for a few hours and my brief was to study the RF converter and report back. However, I obviously did have to use the PC GUI that came with the instrument.In my opinion the actual spectrum display was quite pleasing and it really is nice to see a big colour screen showing the spectrum. But the user interface for the classic analyser controls was obviously written by a disinterested software engineer (AKA a 'typist') because the control menus were very fiddly to use and placed far apart. The overall experience was a bit clunky and slightly irritating because it could easily have been a lot better. But I suppose this can easily be changed with an upgrade if they have another attempt with some input from a typical end user.I didn't have time to play with data capture or data processing on the PC but I expect that this is one area where the instrument will shine because Tek already have a fair bit of experience in the RTSA market.

author: ElectroIrradiator
author_rank: Frequent Contributor
timestamp: August 05, 2015, 11:56:07 pm
content: Quote from: G0HZU on August 05, 2015, 09:48:44 pmI would like to offer a different perspective, as I am personally quite seriously thinking about putting my own money down for one of these 'new breed' of spectrum analyzers. Specifically the one built into the Tektronix MDO3000 range of DSOs.Some personal background may be in order. I will not claim to be the most exprienced RF/high frequency guy on the planet, nor the most sophisticated SA user there ever was. However I would like to believe my level of sophistication is somewhat beyond what you just described. I certainly do care about the detailed specifications of any instruments I own or may consider acquiring. If there are relevant techniques or specifications I happen not to know about in connection with them, then I'd certainly like to learn about them ASAP.I do not believe the SA in the MDO3000 range is the best there ever was, not am I blind to its various limitations. Some of these are: SFDR, IMD, (apparent?) phase noise and lack of a TG. Sometimes you can work around these limitations when they get in your way, and sometimes you can't.My philosophy here is that despite these limitations a SA is such an immensely useful tool, that I personally consider it to be a key part of the proverbial swiss army knife for the interested RF/high speed electronics experimenter.Most of the time, when I use one of my instruments, I don't even scratch the possibilities nor push the limits of a given piece of gear. It is mostly bread-and-butter measurements, where I just use a high quality instrument because I happen to have it. If said piece of equipment magically lots the top of its high performance, it would still be quite useful for a lot of use cases, for much of the time I would spend with it.The trouble I sense in for instance the online reviews are two fold.Firstly, the super experienced people like Shahriar have a huge selection of gear to choose from. So he might not use a SA just to measure the power level of an oscillator, instead picking one of his dedicated high precision RF power meters for the job. But if you lack such an instrument, then a SA can of course easily do something as simple as this. Assuming, that is, you are happy about the accuracy of the measurement you get. For many types of experiments and personal educational tasks then yes, plus/minus a dB or so will do quite nicely. We are not all trying to develop the latest and greatest in satellite receiver technology, or something of similar sophistication.On the other hand today only people like yourself, who have lots of experience with SAs and RF, also tend go out of your way to acquire one. This is a catch 22 for all the rest of the people out there. Today a SA is hard/expensive to get (new or possibly even just used), so few people without access to one know or realize just how useful they can be in many situations. So when you give them one to review, they frequently won't know how to demonstrate how useful it can be, despite any limitations.A different way of putting this is thinking of DSOs versus analog scopes. Imagine you only have experience with fully analog scopes. Then suddenly somebody puts a Rigol DS1052E in your lap and asks for a review. I will submit that most people in that situation would not showcase the DSO to its full capacity. Yet despite this few people with experience with DSOs would argue that even a DS1052E - with all its limitations - doesn't make a lot of new measurements possible, compared to those available just with access to an analog scope.If I do decide to buy one of the MDO3000 scopes, then I won't suddenly expect that I am, say, equipped to do proper EMC testing. Yet since I don't already have a SA in my home lab, then I'd *much* rather have a neat, new instrument like the MDO3000 than be completely without one.The main reason why I don't already have one of the MDO3000 scopes is that I am not a famous blogger, who knows how to complain about the 'slow' interface. So I will unfortunately have to pay for it myself.It is getting late, so I'd better stop here. Hope I am making at least a bit of sense.

author: G0HZU
author_rank: Super Contributor
timestamp: August 06, 2015, 12:15:28 am
content: QuoteI'm not sure who you are referring to here but you did make me laugh out loadIt does seem odd that manufacturers give out $$$ test gear as gifts to bloggers like this. What is even stranger is that they don't seem to demo them properly. But I guess my version of a 'proper demo' isn't mainstream or box office. I guess I'm making the same point over and over...I noticed that one part time blogger has been gifted a Tek scope/analyser that must have cost more than I paid for EVERY item of test gear I have ever bought over a 30-35 year timeframe. i.e. the entire contents of two rooms including my furniture. If you include all their other freebies it's probably nearly double

author: w2aew
author_rank: Super Contributor
timestamp: August 06, 2015, 01:18:16 am
content: Quote from: G0HZU on August 05, 2015, 11:40:12 pmFYI - the latest version of the UI (SignalVu-PC) has moved some controls and such around on the display - to group them together more logically and functionally. So, rather than have Center Frequency, Reference Level, Span and RBW located far from each other - they are now grouped together in a ribbon along the bottom of the UI - making it easier to find and adjust. They were placed on the bottom so that tablet users don't cover the display with their hand when they go to adjust the "big four". I think you can see this on the screen shot that I posted earlier showing the SDFR improvement (under those conditions).

author: KE5FX
author_rank: Super Contributor
timestamp: August 06, 2015, 02:45:23 am
content: Quote from: joeqsmith on August 06, 2015, 01:30:43 amWhat'd you think?

author: Rupunzell
author_rank: Frequent Contributor
timestamp: August 06, 2015, 03:19:52 am
content: Bad drives out the good, pandering to what is know to be a larger market to increase profits.There has and always will be a hobby electronics market. This is a very GOOD thing as it allows enthusiast access to tools (instrumentation and such) to further their passion, interest and knowledge of electronics overall.What has happened with the boom of cyber based everything is the discounting and alteration of user expectations of tools and information presented and accessed by this generation of users. It remains best in many ways to be honest and straight forward about the limitations of low cost test gear, point out their inherent limitations and strengths rather than simply advertise-market on features that appear to be useful. It seems today, any techno widget that offers less than a complete set of every imaginable feature is not desirable. Couple that with the user believe that if they are not getting every possible feature, they are not getting their money's worth.Readers, followers should be aware of the potential bias built into any published review, test or advertisement as those who do this work need funding to keep their lights on, question is where does the funding and access to items being reviewed come from?Those involved with promoting and reviewing these USB based instrumentation should be honest and frank about their limitations and what they do best and educate their audience on why these limitations and strengths matter. This methodology is in the tradition of application notes and papers written to help their end users get the very most out of their offerings and further their education on each specific topic.I'm not convinced that USB and PC based instrumentation is the solution to many instrumentation needs. This has happened due to the amount of computing power and capability for their cost. What is almost never discussed or mention is the fact that any switching device can and does generate RF interference both radiated and conducted. How much varies greatly dependent on the specific device in question. How do these factors affect measurement accuracy and how much error is a result of these innate problems. This does not mean USB and PC based instrumentation are all poor, it just means one needs to be fully aware of these potential problems and never take them for granted.How many O'scope users have been fooled and spent countless hours trying to figure out a problem that never was as a result of high distortion probes, poor probing techniques and numerous related basic measurement skills errors?The current generation of computer, keyboard, software centric users can be so easily lure into a sense of security by what has been presented to them on screen or by software, yet the reality of what is actually happening in a circuit or system can be completely different. The only real defense against this self deception is to fully understand what any given measurement should be rather than completely trusting any item of instrumentation or data presented by software via any display.Software should be bug free as delivered. Updates should only happen when absolutely required for functionality and overly common practice of updating OS and software as a must is pure folly IMO.What should be most valued in any spectrum analyzer is it's front end. All that follows is mostly dress up and could be added as required. This is the beauty of computer centric instrumentation, software can be modified as required. But users should be fully aware that actual performance and limitations are baked into the front end and no amount of software can make up for poor front end performance.I'm guessing that most would consider me a bigoted cronemudgeon who has rather fixed expectations of what quality instrumentation must be and not willing to compromise.The first spectrum analyzer owned was a hewlett packard 141T system with several plug ins, tracking generator and pre-selector during the 1980's. This was not an inexpensive item to have in the home lab, it was used a LOT and eventually replaced with newer SAs over time. I'm still of the opinion that ownership of a SA like the 141T or 140T remains quite valuable as a learning tool as full documentation is easily available with spares available as needed. What desist and discourages ownership of instrumentation like the 140 series spectrum analyzers is their size, bulk and lack of PC friendly and centric interface.BerniceUp until maybe 5 years ago I would completely agree with you and so would a lot of engineers. But I really do think that there has been a change away from the traditional (and expected) design integrity of a decent spectrum analyser. I think a significant chunk of today's users don't care much about spurious free dynamic range or many of the other benchmark tests associated with a spectrum analyser. i.e. they won't care (or even understand or even want to understand) the limitations of the RF converter in the instrument. They will simply want to buy it and use it and just accept what they see on the display unless there is an obvious anomaly.For many users the features that are offered by the back end DSP and the amount of analysis bandwidth are the key features they want. If they can get these features cheaper by buying an instrument without the classic designintegrity expected in the RF converter of of a traditional analyser they will choose that option because they probably don't fully understand what tradeoffs they are actually making. In many cases their decision will prove to be OK because they may well never use the instrument in a way that shows up the design compromises of the cheaper instrument.So I think it's a case of giving the customer what they want and being less open about the true limitations of the instrument. For example, the glossy datasheets for lower cost analysis instruments (from the major manufacturers) often concentrate on the back end analysis features but will deliberately be very vague about the specifications and capability of the RF converter section.So you generally won't see the classic performance data that you normally expect to see from a classic HP/Agilent lab analyser. Less info here is 'more'

author: rs20
author_rank: Super Contributor
timestamp: August 06, 2015, 03:43:05 am
content: Quote from: joeqsmith on August 06, 2015, 01:30:43 amFWIW, those are slightly different beasts: VNAs rather than the SNAs, and accordingly $8k instead of $1k5.

author: vk6zgo
author_rank: Super Contributor
timestamp: August 06, 2015, 04:13:19 am
content: Even quite reasonable "standalone" SA's can fool you.I've spoken before about the very nice IFR unit we had at my last work.A PLL on the DUT had lost lock,& shifted from 433MHz to its default frequency of 470MHz.(The fault was lost data due to a faulty plug on the ribbon cable from the PIC.)The IFR showed this as a number of carriers distributed over that frequency range.(Every time it sampled,the carrier was at a different frequency,so each sample was displayed as a discrete frequency.)We spent ages trying to find the cause of all these spurii!!A nasty,"cheapie" Atten analog device showed us the carrier as it shifted,& the error of our ways!

author: hendorog
author_rank: Super Contributor
timestamp: August 06, 2015, 04:16:37 am
content: QuoteThat one will hit a nerve with any serious software developer. It is well known that it is impossible to develop bug free software.This isn't some attitude, its impossible.Therefore, accepting that everything ships with both known and unknown bugs, the hardest decision is simply deciding when to ship.

author: dadler
author_rank: Unknown
timestamp: August 06, 2015, 04:25:33 am
content: As we say in my line of work:"No code has no bugs."And both meanings are fully intended.

author: rs20
author_rank: Super Contributor
timestamp: August 06, 2015, 04:50:10 am
content: Quote from: dadler on August 06, 2015, 04:25:33 amI disagree with one meaning: processor-free ("no-code") designs can absolutely have bugs.

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: August 06, 2015, 05:01:57 am
content: Quote from: hendorog on August 06, 2015, 04:16:37 amIndeed. Software should ship in a state where all functionality that it has been marketed with work as advertized, and where the core functionality doesn't exhibit any major show-stopping bugs.Bugs per se aren't a problem, the problem is when what at best is beta software is shipped where major parts of the functionality are broken.

author: Rupunzell
author_rank: Frequent Contributor
timestamp: August 06, 2015, 05:10:08 am
content: Software must out their nose to the keyboard and screen and work until the software is bug free. This has been done and can be done if honest effort is put forth and stated design requirements DO NOT CHANGE.Software developers must write, test, verify their software-firmware as if their life depended on it. Management must understand why this makes a difference for users and why it is of such importance. Profits should be put secondary to customer-user experience as this builds brand identity and user-customer confidence in their product.It's that simple, anything less is not acceptable.BerniceThat one will hit a nerve with any serious software developer. It is well known that it is impossible to develop bug free software.This isn't some attitude, its impossible.Therefore, accepting that everything ships with both known and unknown bugs, the hardest decision is simply deciding when to ship.

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: August 06, 2015, 05:34:05 am
content: Quote from: Rupunzell on August 06, 2015, 05:10:08 amThat is BS. Software can't be completely bug free, that's a simple fact. The main reason is that software is impossible to test for every possible scenario. The only thing one can do is to test for a sufficient number or cases so that the worst bugs can be eliminated.Even the software you believe is bug free has bugs. Just because you don't see them doesn't mean there aren't any.Even highly safety-critical software has bugs.QuoteAgain, software can't be completely bug free. All you can do is to eliminate the worst one (especially show stoppers) so to reduce the likelihood of the user experiencing one, but you can't eliminate it. In general, the costs of fixing them also increase exponentially with the number of bugs solved, which means at some point it's just not worth fixing any more.QuoteIt's that simple only in the mind of someone who hasn't written any even only moderately complex piece of software, or done software testing for a living. But just because you believe it's that easy doesn't mean it conforms with reality.

author: Rupunzell
author_rank: Frequent Contributor
timestamp: August 06, 2015, 05:47:20 am
content: Increasing complexity often results in non-linear increase of possible problems.This is why reducing complexity as much as possible to directly address a problem for a given result works.More is often not better.Bernice

author: joeqsmith
author_rank: Super Contributor
timestamp: August 06, 2015, 06:35:31 am
content: Quote from: KE5FX on August 06, 2015, 02:45:23 amWe were looking to replace our HP8753s after we hand another unit fail. I personally did not evaluate the system but spoke with the person who did. They were very impressed with it. There was a spur they found that was caused internally of the unit that they were surprised we found. It was not a concern to us in what we would use them for.

author: hendorog
author_rank: Super Contributor
timestamp: August 06, 2015, 06:43:47 am
content: QuoteYep, this is the hard part about deciding when to ship - pressures build up for non-technical reasons and often poor decisions are made by non-technical management operating with imperfect information. Organisations with better processes are better at it.QuoteIt _always_ does! Unfortunately the productivity hit from discarding the OS, discarding any libraries, discarding any COTS hardware/CPU's and designing it all from scratch to precisely fit the minimum viable set of requirements is too severe. The scopes which are based on Windows or Linux or xyz OS mean that a heap of stuff arrives for free and doesn't need to be built.The reality is that every line of code written makes assumptions. The human brain can't cope with the level of complexity required to know every possible interaction at every level from the hardware up to the application. Because of that testing is needed as a _fallback_, and anyone who knows testing should know that you can't test in quality.This is an interesting writeup about the extreme end of software:http://www.fastcompany.com/28121/they-write-right-stuffquote:"It's like pre-Sumerian civilization," says Brad Cox, who wrote the software for Steve Jobs NeXT computer and is a professor at George Mason University. "The way we build software is in the hunter-gatherer stage."

author: tggzzz
author_rank: Super Contributor
timestamp: August 06, 2015, 07:26:13 am
content: Quote from: hendorog on August 06, 2015, 06:43:47 amJust so. Many people have forgotten than both HP and Tek used to ship test equipment based on Smalltalk (Windoze more-or-less didn't exist then)

author: KE5FX
author_rank: Super Contributor
timestamp: August 06, 2015, 11:57:36 pm
content: Quote from: Rupunzell on August 06, 2015, 05:10:08 amThat can be done, and in some industries itisdone. But I don't think you're going to like the price tag.

author: hendorog
author_rank: Super Contributor
timestamp: August 07, 2015, 12:50:21 am
content: QuoteDead right. Not to mention that while spending all that time and (someone elses) money on super high quality work, technology, or the market shifts and makes your product irrelevant.

author: pascal_sweden
author_rank: Super Contributor
timestamp: August 07, 2015, 01:16:05 am
content: Back in the old days, they used to have 2 test engineers for every software engineer.I think they now have 1 test engineer for every 10 software engineers.Is this a natural evolution of Scrum, Agile Software Development, and Lean Startups?What happened to Digital Six Sigma? 3.4 defective features / million opportunitiesCommon jokes among engineers:"It's not a bug, It's a feature""We could do better, but have you seen our competitors? We suck the least""It's not a hardware issue. It's a software bug. No, it's not a software bug. It's a hardware issue""Or maybe it's the firmware?"

author: hendorog
author_rank: Super Contributor
timestamp: August 07, 2015, 01:38:19 am
content: QuoteIf you can spare a few bucks, this book is a very clever parody of what life is like in the seriously dysfunctional corporate IT world:http://www.amazon.com/The-Phoenix-Project-Helping-Business-ebook/dp/B00AZRBLHOThere is some really good clever stuff in there taken from the Toyota/six-sigma/TQM world and how it can be applied to modern software development and IT.At my last job we were all asked to read it, and it actually really helped us break down some corporate silos and get people working together as a team. The same principles apply to product development - hardware vs software vs firmware vs project management.The batch sizing/queuing theory stuff and Kanban is really interesting too - there is a board game (I think it was this onehttp://getkanban.com/) which really demonstrates how getting control of processes can pay off in throughput and productivity.It was also fun putting names of your colleagues to the characters in that book

author: Bud
author_rank: Super Contributor
timestamp: August 07, 2015, 02:21:26 am
content: @KE5FXSorry to steer off topic but since you are here- are you the author of 7470 ? If so can you tell if the GPIB adapter from the other thread work with your software ? (may be you could throw a line there)https://www.eevblog.com/forum/testgear/flood-of-new-agilent-82357b-gpib-usb-adaptors-on-ebay-the-real-deal/

author: KE5FX
author_rank: Super Contributor
timestamp: August 07, 2015, 07:17:20 am
content: Quote from: Bud on August 07, 2015, 02:21:26 amYes, that's me, and I actually just bought 3 of those for a $100/each best offer. Assuming they are the real deal, they should work OK with most of the toolkit apps after you enable NI488.2 compatibility in the Agilent config utility.I'm going to try to support them natively to dispense with that step.

author: Bud
author_rank: Super Contributor
timestamp: August 07, 2015, 02:40:24 pm
content: Thank you very much Sir and good to have you on the Forum.

author: G0HZU
author_rank: Super Contributor
timestamp: August 07, 2015, 07:43:27 pm
content: QuoteYes, the RSA306 offers some neat RTSA capabilities over a wide BWNote that for some tests of SFDR (eg IP3 vs DANL) I found the little RSA306 gave similar performance to an HP8566B. I didn't have enough time to do lots of testing for this so I just did a few classic checks. So in some areas it performed quite well considering its SWaP limitations. But the HP8566B has a fairly weak first mixer on its 0-2500MHz range and it's the only (classic) high performance lab analyser we never ever bought or rented at work because of this. It was very expensive too!For the frequency bands we were covering back then there were better choices when looking for decent IP3 and 2HI performance. eg the HP8568B and especially the TR4172 from Advantest which easily outclassed them both here with its 8 diode first mixer and +22dBm LO drive level